The longevity & health glossary

200+ terms across peptides, hormones, TRT, biological age, supplements, sleep, and training. Plain-English definitions with normal ranges and source data — not marketing claims.

201 terms across 17 categories
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1 term
1RM (One-Rep Max) Max strength Training
The maximum weight you can lift for one rep. Used to calculate training percentages; many programs prescribe sets at % of 1RM.
Normal Range
Test directly or estimate via Epley formula
Read deeper → Strength Training
A
A
15 terms
Allostatic Load Chronic stress burden Aging
The cumulative wear-and-tear on the body from repeated activation of the stress response. One of the strongest predictors of accelerated aging and disease. Driven by chronic psychological stress, poor sleep, and inflammation.
Normal Range
Measured via cortisol patterns, inflammation markers, and metabolic dysregulation
Read deeper → Meditation Effect
Autophagy Cellular cleanup Aging
The process by which cells digest and recycle damaged components. Activated by fasting, exercise, and rapamycin. Declines with age, contributing to accumulation of cellular damage.
Normal Range
Triggered by 16+ hour fasts, intense exercise, caloric restriction
Read deeper → Biological Age Drop
Aerobic Capacity See VO2 Max Cardiovascular
The maximum rate at which the body can consume oxygen during exercise. The single best predictor of all-cause mortality.
Normal Range
30-45 mL/kg/min sedentary, 45-55 active, 55+ athletic (males 30-35)
Read deeper → Zone 2 Cardio
Atrial Fibrillation (AFib) A-fib, irregular rhythm Cardiovascular
Irregular and often rapid heart rhythm. Massively elevates stroke risk. Often detected first by smartwatches. Risk increases with age, alcohol, obesity, and overtraining.
Normal Range
Apple Watch and Oura now offer FDA-cleared AFib detection
Read deeper → Wearable Comparison
Alzheimer's Biomarkers Amyloid beta, Tau, p-Tau Cognitive
Blood and CSF markers that detect Alzheimer's pathology decades before symptoms. Modern blood tests (Quest, LabCorp) can now detect amyloid/tau accumulation.
Normal Range
Available to consumers as of 2024-2025
Read deeper → Blood Tests
APOE4 Apolipoprotein E ε4 Cognitive
A genetic variant that increases Alzheimer's risk 3-12x depending on copies. ~25% of the population carries 1 copy; ~2% carry 2. Modifiable through lifestyle: Mediterranean diet, exercise, sleep, lipid management.
Normal Range
Test via 23andMe or clinical genetics
Read deeper → Biological Age Drop
AGEs Reader Skin autofluorescence Diagnostics
A device that measures accumulated AGEs (Advanced Glycation End-products) in the skin via UV fluorescence. Non-invasive proxy for tissue aging. Available at some clinics.
Normal Range
Lower scores = better metabolic health
Read deeper → Blood Tests
AMH (Anti-Müllerian Hormone) Ovarian reserve marker Hormones
A hormone reflecting the remaining egg supply in females. Used to assess fertility and predict timing of menopause. Declines with age.
Normal Range
Highly age-dependent; specialist interpretation needed
Read deeper → Blood Tests
Apolipoprotein B (ApoB) apoB Lipid
The single most important biomarker for cardiovascular disease risk. Counts every atherogenic particle in your blood. More predictive than LDL cholesterol.
Normal Range
Optimal <60 mg/dL; <80 average; >100 elevated risk
Read deeper → Blood Tests
Autonomic Nervous System (ANS) Sympathetic + Parasympathetic Nervous System
The involuntary control system regulating heart rate, breathing, digestion, and stress response. Split into sympathetic (fight-or-flight) and parasympathetic (rest-and-digest). HRV measures the balance.
Normal Range
Healthy adults show ANS flexibility — fast switch between states
Read deeper → HRV Guide
AOD-9604 Fat-loss peptide Peptides
A fragment of growth hormone marketed for fat loss. Evidence is modest at best. Less robust than the marketing claims.
Normal Range
Off-label; not FDA-approved in US for fat loss
Read deeper → Longevity Stack
Acarbose Glucose blocker Pharmaceuticals
An α-glucosidase inhibitor that slows carbohydrate absorption. Extends lifespan in mice; modest data in humans. Cheap and well-tolerated except for GI side effects.
Normal Range
25-100mg with carb-containing meals; Rx
Read deeper → Longevity Stack
AHI (Apnea-Hypopnea Index) Sleep apnea severity Sleep
Number of apneas/hypopneas per hour of sleep. The standard severity measure for sleep apnea.
Normal Range
<5 normal; 5-15 mild; 15-30 moderate; >30 severe
Read deeper → Sleep Rules
AG1 (Athletic Greens) Greens powder Supplements
A multivitamin/multimineral/greens powder blend. $99/month — expensive for what it is. Useful for those who don't eat varied diets; replaceable with a $20 multivitamin + actual vegetables.
Normal Range
Once daily; many cheaper alternatives exist
Read deeper → AG1 Review
Ashwagandha KSM-66, Sensoril Supplements
An adaptogenic herb that reduces cortisol and improves sleep. Moderate evidence for stress and anxiety reduction.
Normal Range
300-600mg KSM-66 daily
Read deeper → Sleep Rules
B
B
11 terms
Biological Age Evolving Age™ Aging
An estimate of how old your body actually is, based on biomarkers — not your birthday. Measured via blood-based clocks (Horvath, GrimAge, PhenoAge, DunedinPACE) or composite scores from wearable + lifestyle data.
Normal Range
Goal: biological age 5-10 years below chronological age
Read deeper → Biological Age Drop
BMI (Body Mass Index) kg/m² Body Comp
A height-to-weight ratio. Useful as a rough screen, terrible for athletes and muscular individuals. Body fat percentage and waist circumference are more meaningful for most people.
Normal Range
18.5-24.9 normal range — but context-dependent
Read deeper → Protein Experiment
Body Fat Percentage BF% Body Comp
The proportion of total body weight that's fat tissue. Measured most accurately via DEXA scan. Far more meaningful than BMI for health and aesthetics.
Normal Range
Males: 10-20% healthy, 6-13% athletic. Females: 18-28% healthy, 14-20% athletic
Read deeper → Protein Experiment
Brown Adipose Tissue (BAT) Brown Fat Body Comp
A type of fat tissue that burns calories to generate heat (thermogenesis). Activated by cold exposure. Adults typically have very little, but it can be increased with regular cold exposure.
Normal Range
Highest in lean, cold-acclimated individuals
Read deeper → Cold Plunge Data
BDNF Brain-Derived Neurotrophic Factor Cognitive
A protein that supports neuron survival and growth. "Miracle-Gro for the brain." Boosted by exercise (especially Zone 2), intermittent fasting, sleep, and some supplements (Lion's Mane, omega-3).
Normal Range
Higher levels = better cognition, mood, learning
Read deeper → Zone 2 Cardio
Blue Zones Longevity hotspots Diet
Five regions with extraordinarily high concentrations of centenarians: Sardinia, Okinawa, Nicoya, Ikaria, Loma Linda. Common traits: plant-heavy diet, daily movement, social connection, sense of purpose.
Normal Range
Lessons: 80% rule, plant-heavy meals, walking, community
Read deeper → Daily Three
BPC-157 Body Protection Compound Peptides
A peptide derived from a stomach protein, popular for tendon, ligament, and gut healing. Strong animal data, limited human trials. Sold via compounding pharmacies and gray-market sources.
Normal Range
Typical dose 250-500 mcg/day subcutaneous, 4-6 weeks
Read deeper → Longevity Stack
Bempedoic Acid Nexletol Pharmaceuticals
A non-statin lipid-lowering drug. Good option for statin-intolerant patients. Lowers LDL ~20%.
Normal Range
180mg daily; Rx
Read deeper → Blood Tests
Berberine Plant alkaloid Supplements
A natural compound that lowers blood glucose, improves insulin sensitivity, and reduces lipids. "Nature's metformin" — though less potent.
Normal Range
500mg 2-3x daily with meals
Read deeper → Longevity Stack
Blood Flow Restriction (BFR) Occlusion training Recovery
Light-weight training with cuffs restricting venous return. Builds muscle and strength at low loads — useful for injury recovery and older adults.
Normal Range
30-40% 1RM with 50-80% arterial occlusion
Read deeper → Strength Training
Berberine See Pharmaceuticals Supplements
See Pharmaceuticals section. Plant compound that mimics metformin.
Normal Range
500mg 2-3x daily
Read deeper → Longevity Stack
C
C
15 terms
Cellular Senescence Zombie cells Aging
Cells that have stopped dividing but refuse to die — they secrete inflammatory signals (SASP) that damage neighboring tissue. One of the 12 hallmarks of aging. Cleared by senolytic compounds like fisetin and quercetin.
Normal Range
Accumulates with age; targeted by senolytic protocols
Read deeper → Biological Age Drop
Cardiac Output CO Cardiovascular
The amount of blood the heart pumps per minute. Heart rate × stroke volume. Higher cardiac output at lower heart rates indicates better cardiovascular fitness.
Normal Range
4-8 L/min at rest in healthy adults
Read deeper → HRV Guide
Coronary Artery Calcium Score (CAC) Calcium scan Cardiovascular
A CT scan measuring calcified plaque in coronary arteries. The best single predictor of heart attack risk. Score of 0 = essentially zero 10-year risk. Costs $100-300.
Normal Range
Score 0 ideal; 1-99 mild; 100-300 moderate; 400+ severe
Read deeper → Blood Tests
Carotid Intima-Media Thickness (CIMT) Carotid ultrasound Cardiovascular
Ultrasound measurement of artery wall thickness in the carotid arteries. Detects early atherosclerosis before plaque forms. Often used in younger people where CAC is still zero.
Normal Range
Age-adjusted; below 50th percentile is ideal
Read deeper → Blood Tests
Cognitive Reserve Brain resilience Cognitive
The brain's capacity to compensate for damage. Built by education, lifelong learning, social engagement, exercise, and second-language acquisition.
Normal Range
Higher cognitive reserve delays dementia onset by years
Read deeper → Daily Three
CT Calcium Scan Coronary calcium scan Diagnostics
See Coronary Artery Calcium Score (CAC). Low-dose CT of the heart to detect plaque calcification.
Normal Range
$100-300; should be done by 40-45 for most adults
Read deeper → Blood Tests
Caloric Restriction (CR) CR Diet
Reducing calorie intake (typically 20-30%) while maintaining nutrient density. The most consistently life-extending intervention across species. Hard to sustain in humans.
Normal Range
Most research uses 15-25% reduction below ad-libitum intake
Read deeper → Longevity Stack
Cortisol Stress hormone Hormones
A glucocorticoid hormone with a natural daily rhythm. High in the morning, low at night. Chronic elevation from stress damages sleep, immune function, body composition, and HRV.
Normal Range
Highest 30-45 min after waking (cortisol awakening response), lowest at bedtime
Read deeper → Evening Routine
Cerebrolysin Neurotrophic peptide complex Peptides
A peptide mix derived from pig brain, used in Europe and Asia for stroke recovery and dementia. Some evidence for cognitive support. Not FDA-approved in the US.
Normal Range
IM injection courses prescribed abroad
Read deeper → Biological Age Drop
CJC-1295 GHRH analog Peptides
A growth hormone-releasing hormone analog that stimulates pulsatile GH release. Often stacked with Ipamorelin. Half-life ~7 days with DAC version, hours without.
Normal Range
Off-label; underground bodybuilding and anti-aging use
Read deeper → Longevity Stack
Contrast Therapy Hot-Cold alternation Recovery
Alternating sauna and cold plunge. May produce greater HRV benefit than either alone, though personal data varies.
Normal Range
2-3 minute cold → 10-15 minute sauna, 2-4 cycles
Read deeper → Sauna and Cold
Chronotype Sleep type Sleep
Your innate disposition toward being a morning or evening person. Genetically determined (~50%) and influences when you naturally feel alert vs. sleepy.
Normal Range
~25% early types, ~25% late types, ~50% intermediate
Read deeper → Evening Routine
Circadian Rhythm Body clock Sleep
Your roughly-24-hour internal biological clock regulating sleep, hormones, body temperature, and metabolism. Disrupted by inconsistent sleep, late light exposure, and shift work.
Normal Range
24h cycle, anchored by light exposure
Read deeper → Bedtime Protocol
CPAP Continuous Positive Airway Pressure Sleep
The standard treatment for obstructive sleep apnea. A mask delivering pressurized air to keep the airway open.
Normal Range
Prescribed after polysomnography diagnosis
Read deeper → Sleep Rules
Creatine Monohydrate CM Supplements
A naturally-occurring compound that increases ATP regeneration. The most-researched supplement in existence. Benefits: strength, muscle, cognition, sleep, bone density.
Normal Range
5g daily; full effects at 21-28 days
Read deeper → Creatine Experiment
D
D
6 terms
DunedinPACE Pace of Aging clock Aging
A DNA methylation clock that measures the pace at which you are aging (years per chronological year), rather than total biological age. Sensitive to lifestyle interventions over short timeframes.
Normal Range
1.0 = aging at normal pace. <0.9 = slowing; >1.1 = accelerated
Read deeper → Biological Age Drop
DEXA Scan DXA Diagnostics
Dual-energy X-ray absorptiometry. The gold standard for measuring body composition — lean mass, fat mass, visceral fat, and bone density. Costs $50-150 per scan.
Normal Range
Recommended every 6-12 months for serious body comp tracking
Read deeper → Protein Experiment
DHEA Dehydroepiandrosterone Hormones
A precursor hormone made by the adrenals that converts to testosterone and estrogen. Declines 80%+ from age 25 to 75. Supplementation modestly studied; mixed results.
Normal Range
Optimal 200-300 µg/dL (males), 150-250 (females)
Read deeper → Blood Tests
DHT (Dihydrotestosterone) Active T metabolite Hormones
The most potent androgen, formed from testosterone via 5α-reductase. Drives muscle, libido, but also hair loss and prostate enlargement. Blocked by finasteride.
Normal Range
Adult males 30-85 ng/dL
Read deeper → Blood Tests
DSIP (Delta Sleep-Inducing Peptide) Sleep peptide Peptides
A neuropeptide that promotes slow-wave (deep) sleep. Modest evidence; popular in biohacker circles.
Normal Range
100-500 mcg subcutaneous before bed (off-label)
Read deeper → Sleep Rules
Deep Sleep Slow-Wave Sleep, SWS, N3 Sleep
The deepest, most physically restorative stage of sleep. When growth hormone releases, immune function strengthens, and physical recovery happens.
Normal Range
13-23% of total sleep, ~70-100 min in a 7-8h night
Read deeper → Sleep Rules
E
E
8 terms
Epigenetic Clock DNAm age Aging
Algorithms that estimate biological age from DNA methylation patterns. The gold standard for measuring biological aging. Most popular: Horvath, Hannum, GrimAge, PhenoAge, DunedinPACE.
Normal Range
Available via TruDiagnostic, Elysium Index, MyDNAge
Read deeper → Biological Age Drop
Epigenetics Above the gene Aging
Changes in gene expression that don't alter DNA sequence — driven by methylation, histone modifications, and non-coding RNA. Highly responsive to lifestyle, nutrition, stress, and toxins.
Normal Range
Modifiable across the lifespan
Read deeper → Biological Age Drop
Evolving Age™ EL Biological Age Aging
Evolving Longevity's proprietary biological age estimate based on 8-11 wearable + lifestyle inputs. Calculated against published population norms for your cohort. Updates daily with new data.
Normal Range
Goal: 5+ years below chronological age
Read deeper → Biological Age Drop
Endothelial Function Vascular health Cardiovascular
How well your blood vessel lining dilates in response to stimuli. The earliest measurable sign of cardiovascular disease. Measured via flow-mediated dilation (FMD).
Normal Range
Improved by Zone 2 cardio, sauna, beetroot/nitrates, omega-3
Read deeper → Sauna and Cold
Estradiol (E2) Primary estrogen Hormones
The main estrogen in cycling females, also important in males. Critical for bone density, cardiovascular health, libido, and mood in both sexes.
Normal Range
Male: 10-40 pg/mL. Female: highly cycle-dependent
Read deeper → Blood Tests
Epitalon Epithalon Peptides
A 4-amino acid peptide developed in Russia, marketed for telomere lengthening and longevity. Limited high-quality human evidence, mostly Russian studies.
Normal Range
Typically dosed in cycles, e.g. 10 days every 6 months
Read deeper → Biological Age Drop
Eccentric Loading Negative phase training Training
Emphasizing the lengthening phase of a lift (lowering). More muscle damage and growth per rep than concentric work. Useful for hypertrophy and tendon strength.
Normal Range
4-6 second negatives in tempo training
Read deeper → Strength Training
Excess Post-Exercise Oxygen Consumption (EPOC) Afterburn Training
The elevated oxygen consumption (and calorie burn) that continues after exercise ends.
Normal Range
5-15% of workout calorie burn for typical sessions
Read deeper → Zone 2 Cardio
F
F
7 terms
Full-Body MRI Prenuvo, Ezra, Galleri Diagnostics
A whole-body MRI screening for early cancer, aneurysms, organ abnormalities. Controversial: catches problems early but also generates false positives. Costs $1,000-2,500.
Normal Range
Optional once every 2-3 years over age 40
Read deeper → Biological Age Drop
Fasting-Mimicking Diet (FMD) ProLon, Longo protocol Diet
5-day low-calorie, low-protein diet designed to trigger autophagy and stem cell renewal without complete fasting. Developed by Dr. Valter Longo; commercially available as ProLon (~$200).
Normal Range
5 days, 4-6x per year; cyclical, not continuous
Read deeper → Biological Age Drop
Free Testosterone Bioavailable T Hormones
The portion of testosterone not bound to SHBG/albumin — the biologically active form. Often more meaningful than total T, especially when SHBG is abnormal.
Normal Range
Adult males: 8.7-25.1 pg/mL; optimal 15-25
Read deeper → Blood Tests
Fasting Glucose FBG Metabolic
Blood glucose measured after 8+ hours of fasting. Key marker of metabolic health. Persistently elevated values predict diabetes, cardiovascular disease, and accelerated aging.
Normal Range
Optimal 70-85 mg/dL; <100 normal; 100-125 prediabetic; 126+ diabetic
Read deeper → Blood Tests
Fasting Insulin Insulin Sensitivity Metabolic
Blood insulin measured fasted. Often elevated long before fasting glucose rises — making it an earlier warning sign of insulin resistance.
Normal Range
Optimal <5 µIU/mL; <10 normal; >15 insulin-resistant
Read deeper → Blood Tests
Fibrinogen Coagulation marker Inflammation
A clotting protein that's also an acute-phase inflammation marker. Elevated fibrinogen predicts cardiovascular events and inflammation.
Normal Range
Optimal <300 mg/dL; up to 400 acceptable
Read deeper → Blood Tests
Fisetin Senolytic flavonoid Supplements
A plant flavonoid with senolytic activity. Clears senescent cells in animal models; human evidence emerging.
Normal Range
500mg daily for 5 days/month (research protocol)
Read deeper → Longevity Stack
G
G
9 terms
Glycation (AGEs) Advanced Glycation End-products Aging
Damage caused when sugar binds to proteins, creating dysfunctional cross-linked molecules. Drives skin aging, arterial stiffening, kidney disease. Reduced by lower-sugar diets and lower cooking temperatures.
Normal Range
Measured via blood HbA1c proxy or skin autofluorescence (AGE Reader)
Read deeper → Blood Tests
GrimAge Mortality clock Aging
A DNA-methylation-based biological age estimator that specifically predicts mortality and disease onset. One of the most validated aging clocks. Available via TruDiagnostic.
Normal Range
Goal: GrimAge below chronological age
Read deeper → Biological Age Drop
Galleri Test Multi-cancer early detection Diagnostics
A blood test that screens for 50+ cancers via circulating tumor DNA. FDA-approved early detection, but expensive (~$950) and not yet covered by insurance.
Normal Range
Optional annual screen for high-risk individuals over 50
Read deeper → Blood Tests
Growth Hormone (GH) Somatotropin Hormones
Pulsatile hormone released primarily during deep sleep and intense exercise. Drives recovery, fat metabolism, and protein synthesis. Declines ~14% per decade after 30.
Normal Range
Boosted naturally by sleep, exercise, fasting
Read deeper → Sleep Rules
GGT (Gamma-Glutamyl Transferase) Liver/oxidative stress marker Metabolic
A liver enzyme also elevated by alcohol, oxidative stress, and metabolic dysfunction. An under-recognized marker of aging and mortality.
Normal Range
Optimal <20 U/L; <50 normal
Read deeper → Blood Tests
GHK-Cu Copper Peptide GHK-Cu Peptides
A copper-binding tripeptide used topically for skin and hair, injected for tissue repair. Robust evidence for skin and wound healing.
Normal Range
Topical 1-5%; injection forms off-label
Read deeper → Longevity Stack
GLP-1 Agonists Semaglutide, Tirzepatide, Liraglutide Pharmaceuticals
A class of diabetes/weight loss drugs that mimic the GLP-1 hormone. Among the most impactful medications of the past decade: weight loss, cardiovascular protection, possibly Alzheimer's prevention.
Normal Range
Multiple specific drugs; see Semaglutide, Tirzepatide, Retatrutide
Read deeper → Longevity Stack
Glutathione GSH Supplements
The body's master antioxidant. Oral supplementation is poorly absorbed; precursors (NAC, glycine) are better than direct GSH.
Normal Range
NAC 600-1800mg, or liposomal GSH 500mg daily
Read deeper → Longevity Stack
Grip Strength Hand dynamometry Training
The maximum force you can squeeze. One of the strongest predictors of all-cause mortality.
Normal Range
Males 30s: 100+ lbs strong, 80-100 healthy, <80 declining
Read deeper → Strength Training
H
H
15 terms
Hallmarks of Aging 12 hallmarks (López-Otín) Aging
The 12 interconnected mechanisms driving aging: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, disabled autophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation, dysbiosis.
Normal Range
Each hallmark is a therapeutic target
Read deeper → Biological Age Drop
Healthspan Years of healthy life Aging
The number of years lived in good health, free from chronic disease. Most longevity research targets healthspan extension, not just lifespan. Average healthspan in the US is ~14 years shorter than lifespan.
Normal Range
Goal: compress disease into the final years of life
Read deeper → Biological Age Drop
Horvath Clock DNAm age Aging
The original epigenetic age clock (Steve Horvath, 2013). Uses 353 CpG methylation sites to estimate biological age. The foundational biological age measurement.
Normal Range
Available via TruDiagnostic and similar services
Read deeper → Biological Age Drop
Heart Rate Reserve (HRR) HRmax − HRrest Cardiovascular
The difference between max heart rate and resting heart rate. Larger HRR = better cardiovascular fitness. Used for calculating heart rate training zones via Karvonen method.
Normal Range
Adults: 130-170 bpm range; trained athletes >180
Read deeper → Zone 2 Cardio
HRV Heart Rate Variability Cardiovascular
The natural variation in time between heartbeats. The single best wearable-measurable marker of nervous system health. Higher = more parasympathetic dominance, better recovery, lower stress.
Normal Range
Adult average: 30-65ms rMSSD. Athletic: 60-100ms+. Declines ~5-10ms per decade after 30
Read deeper → HRV Guide
HRT (Hormone Replacement Therapy) Menopause HRT Hormones
Replacement of estrogen ± progesterone in menopausal women. Modern evidence (vs. 2002 WHI scare) shows benefit when started within 10 years of menopause — improves bone density, cardiovascular health, cognition.
Normal Range
Bioidentical estradiol + micronized progesterone is the modern standard
Read deeper → Biological Age Drop
HbA1c Glycated hemoglobin Metabolic
A measure of average blood glucose over the prior 3 months. Standard for diabetes diagnosis and management. Slightly imperfect: anemia and high red cell turnover skew it.
Normal Range
Optimal <5.4%; <5.7% normal; 5.7-6.4% prediabetic; 6.5%+ diabetic
Read deeper → Blood Tests
HOMA-IR Insulin resistance index Metabolic
A calculated value from fasting glucose and insulin. Quantifies insulin resistance with one number.
Normal Range
Optimal <1.0; <1.5 normal; >2.0 insulin-resistant
Read deeper → Blood Tests
Homocysteine Hcy Cardiovascular
An amino acid intermediate that, when elevated, predicts cardiovascular disease and cognitive decline. Lowered by B12, folate, B6.
Normal Range
Optimal <8 µmol/L; <10 normal; >15 elevated risk
Read deeper → Blood Tests
hs-CRP High-sensitivity C-Reactive Protein Inflammation
The standard blood marker for systemic inflammation. Predicts cardiovascular events, accelerated aging, and all-cause mortality.
Normal Range
Optimal <0.5 mg/L; <1.0 low risk; 1-3 moderate; >3 high
Read deeper → Blood Tests
HPA Axis Hypothalamic-Pituitary-Adrenal Nervous System
The body's central stress response system. Chronic activation dysregulates cortisol, sleep, and immune function.
Normal Range
Modulated by meditation, sleep, social connection
Read deeper → Meditation Effect
Hexarelin GH secretagogue Peptides
A potent GH-releasing peptide. More aggressive than Ipamorelin but also raises cortisol and prolactin. Largely superseded by safer alternatives.
Normal Range
Off-label; less commonly used today
Read deeper → Longevity Stack
HBOT (Hyperbaric Oxygen Therapy) Pressure chamber Recovery
Breathing 100% oxygen at elevated pressure (2-2.4 ATA). Strong evidence for wound healing; emerging evidence for cognitive function, telomere length, and recovery. Sessions are 60-90 min, courses 20-40.
Normal Range
Available at specialized clinics; $150-400/session
Read deeper → Biological Age Drop
HIIT (High-Intensity Interval Training) Interval training Training
Short bursts of near-maximum effort alternated with rest. Time-efficient for VO2 Max gains but more recovery-taxing than Zone 2.
Normal Range
1-2 sessions per week for most people
Read deeper → Zone 2 Cardio
Hypertrophy Muscle growth Training
Increase in muscle cell size from resistance training. Driven by mechanical tension, with adequate protein and progressive overload.
Normal Range
~0.5-1 lb of muscle/month in trained males
Read deeper → Strength Training
I
I
8 terms
Inflammaging Chronic low-grade inflammation Aging
The chronic, sterile, low-grade inflammation that develops with age. Drives basically every age-related disease — cardiovascular, cognitive, metabolic, autoimmune.
Normal Range
Measured via hs-CRP, IL-6, TNF-α
Read deeper → Blood Tests
Intermittent Fasting (IF) 16:8, time-restricted eating Diet
Cycling between periods of eating and not eating. Most popular: 16:8 (eat in an 8-hour window). Less impressive than the hype suggests, but useful for caloric control and circadian alignment.
Normal Range
Effects mostly driven by calorie reduction, not magic
Read deeper → Morning Routine
IGF-1 Insulin-like Growth Factor 1 Hormones
A hormone mediating most growth hormone effects. U-shaped curve with longevity — too low = frailty, too high = cancer risk. Modifiable via protein intake.
Normal Range
Optimal range 100-200 ng/mL in adults; varies by age
Read deeper → Protein for Longevity
Insulin See Fasting Insulin Hormones
The hormone that regulates blood glucose. Chronic elevation drives nearly every chronic disease. Modifiable via diet, exercise, sleep, body composition.
Normal Range
Fasting <5 µIU/mL optimal
Read deeper → Blood Tests
IL-6 Interleukin-6 Inflammation
A pro-inflammatory cytokine elevated with infection, injury, obesity, and aging. Chronic elevation drives inflammaging.
Normal Range
<1.5 pg/mL in healthy adults
Read deeper → Blood Tests
Ipamorelin Selective GHRP Peptides
A selective growth hormone-releasing peptide. Stimulates GH without raising cortisol or prolactin — making it the most popular GHRP in anti-aging circles. Commonly stacked with CJC-1295.
Normal Range
Off-label; 200-300 mcg subcutaneous, often 2-3x daily
Read deeper → Longevity Stack
IV Therapy IV vitamin therapy Recovery
Intravenous administration of vitamins, minerals, or amino acids. Most common formulations have weak evidence; targeted forms (iron, vitamin D) for documented deficiency are different.
Normal Range
Mostly cosmetic medicine, not evidence-based
Read deeper → Longevity Stack
Insulin Resistance Metabolic syndrome precursor Metabolic
When cells stop responding properly to insulin. The root cause of type 2 diabetes and a driver of most chronic disease. Reversible early via exercise, diet, and weight loss.
Normal Range
Reversible in most cases with lifestyle intervention
Read deeper → Blood Tests
K
K
2 terms
Ketogenic Diet Keto Diet
Very low-carb (<50g/day), high-fat diet that forces the body to burn ketones instead of glucose. Effective for weight loss, seizure disorders, and some metabolic conditions. Hard to sustain long-term.
Normal Range
Optimal for some, miserable for others — context-dependent
Read deeper → Protein for Longevity
KPV Anti-inflammatory peptide Peptides
A 3-amino acid α-MSH fragment with anti-inflammatory properties. Used for IBD, autoimmune skin conditions, gut inflammation.
Normal Range
200-500 mcg subcutaneous or oral (off-label)
Read deeper → Longevity Stack
L
L
8 terms
Lifespan Total years alive Aging
The total number of years lived from birth to death. Healthspan is usually a more important target. Top mortality predictors: VO2 Max, grip strength, body composition, fasting glucose, ApoB.
Normal Range
US average ~76 years (2024); biological age can shift this ±10 years
Read deeper → Biological Age Drop
Lean Body Mass (LBM) Fat-free mass Body Comp
Everything in your body that isn't fat — muscle, bone, organs, water. The most important body composition target for healthy aging. Preserving LBM is the single biggest determinant of physical function in old age.
Normal Range
Track via DEXA scan every 6-12 months
Read deeper → Protein Experiment
Lactate Threshold LT, Anaerobic Threshold Cardiovascular
The exercise intensity above which lactate accumulates faster than it can be cleared. The boundary between Zone 2 and Zone 3. Endurance training pushes this threshold higher.
Normal Range
~70-80% of VO2 Max in trained individuals
Read deeper → Zone 2 Cardio
Longevity Diet (Longo) Pescatarian-Mediterranean hybrid Diet
Dr. Valter Longo's evidence-based diet: pescatarian, high-vegetable, moderate-protein, with periodic FMD cycles. Designed for longevity, not weight loss.
Normal Range
See Longo's book "The Longevity Diet"
Read deeper → Protein for Longevity
LH / FSH Luteinizing / Follicle-Stimulating Hormone Hormones
Pituitary hormones that control gonadal function. Elevated in primary hypogonadism, suppressed in TRT use.
Normal Range
Male LH 1.7-8.6 IU/L. Female: cycle-dependent
Read deeper → Blood Tests
Lipoprotein(a) [Lp(a)] Lp little a Lipid
A genetic variant of LDL that's independently atherogenic. ~20% of the population has elevated Lp(a). Check once in your lifetime — it doesn't change with lifestyle.
Normal Range
Optimal <30 mg/dL; >50 elevated cardiovascular risk
Read deeper → Blood Tests
Light Sleep N1 + N2 Sleep
The largest portion of overnight sleep — not "shallow" or low-quality. Plays roles in memory consolidation and motor learning.
Normal Range
45-55% of total sleep time is normal
Read deeper → Sleep Rules
Lion's Mane Hericium erinaceus Supplements
A medicinal mushroom that supports BDNF and NGF (nerve growth factor). Modest evidence for cognitive enhancement.
Normal Range
500-2000mg daily (dual-extract preferred)
Read deeper → Longevity Stack
M
M
15 terms
mTOR mechanistic Target of Rapamycin Aging
A central cellular sensor that triggers growth pathways when nutrients (especially leucine and insulin) are high. Suppressed by fasting, rapamycin, and caloric restriction — which extends lifespan in nearly every species tested.
Normal Range
Cyclically active is healthy; chronically active accelerates aging
Read deeper → Protein for Longevity
Mitochondrial Dysfunction Mito decay Aging
Age-related decline in mitochondrial number, efficiency, and DNA integrity. Drives fatigue, cognitive decline, sarcopenia, and metabolic disease. Improved by Zone 2 cardio, creatine, NAD precursors.
Normal Range
Reversible with structured training and supplementation
Read deeper → Zone 2 Cardio
Maximum Heart Rate (HRmax) Peak HR Cardiovascular
The highest heart rate achievable during all-out effort. The "220 minus age" formula is wildly inaccurate — actual HRmax varies ±20 bpm between individuals. Test directly via VO2 Max protocol.
Normal Range
Highly individual; varies more than most realize
Read deeper → Zone 2 Cardio
Mediterranean Diet Med diet Diet
Olive oil, fish, vegetables, whole grains, nuts, legumes, moderate wine. The most consistently health-promoting diet in nutritional research. Tied to lower all-cause mortality, cardiovascular disease, dementia.
Normal Range
The default best-evidence diet for most adults
Read deeper → Protein for Longevity
mTOR Cycling Protein cycling Diet
Intentionally alternating between high-protein/anabolic days and lower-protein days to balance mTOR activation. Theoretically optimal but practically complex.
Normal Range
5-7 days/month at lower protein intake
Read deeper → Protein for Longevity
Melanotan II MT-II Peptides
A synthetic melanocortin agonist marketed for tanning, libido (PT-141 derivative). Side effects significant: nausea, blood pressure changes, mole darkening.
Normal Range
Cosmetic use; meaningful risks
Read deeper → Longevity Stack
MOTS-c Mitochondrial peptide Peptides
A 16-amino acid peptide encoded by mitochondrial DNA. Improves insulin sensitivity, metabolic flexibility, and exercise capacity in animal models. Human data emerging.
Normal Range
Experimental; ~10mg subcutaneous in off-label protocols
Read deeper → Longevity Stack
Metformin Glucophage Pharmaceuticals
A diabetes drug studied extensively for longevity. Evidence is mixed: may extend healthspan but also blunts exercise adaptations. The TAME trial will provide better data.
Normal Range
500-2000mg daily; Rx
Read deeper → Longevity Stack
Melatonin Sleep hormone Sleep
A hormone released by the pineal gland in darkness, signaling sleep. Supplemental doses are usually too high — 0.3-0.5mg is more physiological than 5-10mg.
Normal Range
Suppressed by blue light; rises ~2 hours before natural bedtime
Read deeper → Evening Routine
Magnesium Glycinate Bisglycinate Supplements
A highly bioavailable form of magnesium. Best for sleep, anxiety, and recovery. Most adults are deficient.
Normal Range
200-400mg before bed
Read deeper → Evening Routine
MAF Method 180-age formula Training
Phil Maffetone's aerobic training approach: train below (180 − your age) bpm. A practical Zone 2 proxy, though imperfect.
Normal Range
Useful starting point for Zone 2 work
Read deeper → Zone 2 Cardio
Metabolic Flexibility Fuel switching Metabolic
The ability to efficiently switch between burning fat and carbohydrates depending on availability. Lost in metabolic disease; restored by Zone 2 training and dietary variation.
Normal Range
High in healthy/fit; low in metabolic syndrome
Read deeper → Zone 2 Cardio
Metabolic Syndrome MetS Metabolic
A cluster of 5 markers: elevated waist, blood pressure, triglycerides, low HDL, elevated fasting glucose. Having 3+ predicts massively increased disease risk.
Normal Range
Affects ~33% of US adults
Read deeper → Blood Tests
Mitochondria Cellular powerhouses Metabolic
The energy-producing organelles in cells. Mitochondrial health drives basically everything — energy, cognitive function, aging, recovery.
Normal Range
Quality and quantity both matter; built by Zone 2
Read deeper → Zone 2 Cardio
Mitophagy Mitochondrial cleanup Metabolic
The selective removal of damaged mitochondria. A subset of autophagy. Boosted by exercise, fasting, urolithin A.
Normal Range
Triggered by exercise and caloric stress
Read deeper → Longevity Stack
N
N
8 terms
Neurogenesis New neuron formation Cognitive
The growth of new neurons, primarily in the hippocampus. Active throughout adult life but declines with age. Boosted by exercise, sleep, BDNF, and learning.
Normal Range
~700 new neurons/day in adult hippocampus
Read deeper → Zone 2 Cardio
Neuroplasticity Brain rewiring Cognitive
The brain's ability to reorganize itself by forming new neural connections. Persists throughout life, though slower with age. Driven by novelty, learning, exercise, and quality sleep.
Normal Range
Enhanced via novel learning and stress recovery
Read deeper → Daily Three
Nootropics Cognitive enhancers Cognitive
Substances that enhance cognitive function. Best-evidence options: caffeine + L-theanine, creatine, omega-3, Lion's Mane, modafinil (Rx). Most "nootropic stacks" are marketing.
Normal Range
Stick to evidence-based options; avoid proprietary blends
Read deeper → Creatine for Longevity
NAD+ IV NAD infusion Recovery
IV administration of NAD+. Hyped beyond the evidence. Oral NMN/NR likely more practical for most. Useful in some specific addiction recovery protocols.
Normal Range
Expensive ($300-1000+ per infusion)
Read deeper → NAD/NMN/NR Guide
NAC (N-Acetylcysteine) NAC Supplements
A glutathione precursor and antioxidant. Used for liver protection, mucolysis, and possibly cognitive/mood benefits.
Normal Range
600-1800mg daily
Read deeper → Longevity Stack
NAD+ See Aging section Supplements
See Aging section. Boosted via NMN, NR, or NAD IV.
Normal Range
Boost via precursors; declines with age
Read deeper → NAD/NMN/NR Guide
NMN (Nicotinamide Mononucleotide) NAD precursor Supplements
A direct NAD+ precursor. Better-absorbed than NR in some studies, popularized by David Sinclair.
Normal Range
250-500mg daily
Read deeper → NAD/NMN/NR Guide
NR (Nicotinamide Riboside) Tru Niagen, Basis Supplements
An NAD+ precursor. More research than NMN in humans, though NMN is more popular in biohacker culture.
Normal Range
300-500mg daily
Read deeper → NAD/NMN/NR Guide
O
O
6 terms
Oxidative Stress Free radical damage Aging
Imbalance between reactive oxygen species (ROS) and the body's antioxidant defenses. Drives DNA damage, protein dysfunction, and inflammation. Counteracted by glutathione, NAC, vitamin C, sleep.
Normal Range
Reduced via sleep, exercise (paradoxically — hormetic), antioxidants
Read deeper → Evening Routine
OGTT (Oral Glucose Tolerance Test) 2-hour glucose test Diagnostics
Blood glucose measured fasting, then 1-2 hours after 75g glucose drink. The gold standard for diagnosing prediabetes — catches dysfunction missed by fasting glucose alone.
Normal Range
2-hour reading: optimal <120; <140 normal; 140-199 prediabetic; 200+ diabetic
Read deeper → Blood Tests
OMAD (One Meal A Day) 23:1 fasting Diet
Eating only one meal per day. Extreme version of intermittent fasting. Effective for some, but risks muscle loss and adherence issues. Not optimal for athletes or those needing high protein.
Normal Range
Not recommended for most people serious about training
Read deeper → Protein Experiment
Omega-3 Index EPA + DHA Lipid
The percentage of EPA + DHA in red blood cell membranes. Below 4% strongly predicts cardiovascular mortality. Above 8% is the goal.
Normal Range
Optimal >8%; 4-8% moderate; <4% high cardiovascular risk
Read deeper → Longevity Stack
OSA (Obstructive Sleep Apnea) Sleep apnea Sleep
Repeated airway collapse during sleep. Often undiagnosed; massively impacts HRV, recovery, cardiovascular health, and cognition. Worth ruling out if HRV is chronically low.
Normal Range
Wearables now flag this; confirm via sleep study
Read deeper → Sleep Rules
Omega-3 (EPA + DHA) Fish oil Supplements
Essential fatty acids with strong cardiovascular and cognitive benefits. Optimize via Omega-3 Index test.
Normal Range
2-4g EPA+DHA daily for most adults
Read deeper → Longevity Stack
P
P
13 terms
PhenoAge Phenotypic Age Aging
A biological age estimator derived from 9 standard blood markers (albumin, creatinine, glucose, CRP, lymphocytes, mean cell volume, red cell distribution width, alkaline phosphatase, WBC). Cheap and accessible — calculable from a basic blood panel.
Normal Range
Available via online calculators using your existing labs
Read deeper → Blood Tests
Polyphenols Plant compounds Diet
Antioxidant compounds in plants (berries, dark chocolate, green tea, olive oil). Mechanism behind much of the "Mediterranean diet is healthy" finding.
Normal Range
Targeted via diet diversity; 5+ colors of plant foods daily
Read deeper → Protein for Longevity
Protein Leverage Hypothesis Protein priority Diet
The theory that humans eat to meet a fixed protein target, and will overeat carbs/fats if protein is insufficient. Explains why high-protein diets reduce hunger.
Normal Range
Eat protein first; hunger self-regulates
Read deeper → Protein Experiment
Prolactin PRL Hormones
A hormone elevated by stress, sleep, and pituitary tumors. High prolactin suppresses testosterone and libido. Worth checking in males with low libido despite normal T.
Normal Range
Adult male <15 ng/mL; female <25 (non-pregnant)
Read deeper → Blood Tests
Progesterone P4 Hormones
A reproductive hormone that opposes estrogen. Crucial for female cycle, pregnancy, sleep, and mood. Declines sharply in perimenopause.
Normal Range
Female: 0.1-25 ng/mL depending on cycle phase. Male: very low
Read deeper → Blood Tests
Parasympathetic Nervous System Rest-and-Digest Nervous System
The "rest" arm of the autonomic nervous system. Dominates during sleep, meditation, and digestion. High HRV reflects strong parasympathetic activity.
Normal Range
Activated by deep breathing, meditation, cold exposure tail, sleep
Read deeper → Meditation Effect
PT-141 (Bremelanotide) Vyleesi Peptides
A melanocortin agonist that increases sexual desire in both sexes. FDA-approved for HSDD in premenopausal women (Vyleesi). Off-label use in men.
Normal Range
Rx-only; nasal spray or injection
Read deeper → Longevity Stack
PCSK9 Inhibitors Repatha, Praluent Pharmaceuticals
Monoclonal antibodies that dramatically lower LDL/ApoB. For patients with familial hypercholesterolemia or who can't reach targets on statins. Expensive.
Normal Range
Biweekly or monthly injection; Rx
Read deeper → Blood Tests
PEMF Pulsed Electromagnetic Field Recovery
Therapeutic electromagnetic field application. Strong evidence for bone healing; mixed for recovery and pain.
Normal Range
Devices range from $200 (consumer) to $20,000 (medical)
Read deeper → Biological Age Drop
PSG (Polysomnography) Sleep study Sleep
The clinical gold standard for sleep measurement. EEG + ECG + respiratory monitoring + oximetry. Required to diagnose sleep apnea formally.
Normal Range
Done in-lab or via home study; Rx required
Read deeper → Sleep Rules
Pterostilbene Resveratrol analog Supplements
A naturally-occurring compound similar to resveratrol with better bioavailability. Activates sirtuins; antioxidant effects.
Normal Range
50-150mg daily
Read deeper → Longevity Stack
Periodization Training cycles Training
Systematic variation in training volume and intensity over weeks/months. Prevents plateaus and overtraining. Linear, undulating, and block periodization are common models.
Normal Range
4-12 week mesocycles with planned deload weeks
Read deeper → Strength Training
Progressive Overload Gradual increase Training
Gradually increasing demand on the body. The fundamental principle of strength training. Via weight, reps, sets, range of motion, or tempo.
Normal Range
~2-5% weekly progression in beginners; slower in advanced
Read deeper → Strength Training
Q
Q
1 term
Quercetin Flavonoid Supplements
A plant flavonoid with antioxidant and senolytic activity. Often paired with fisetin in senolytic protocols.
Normal Range
500-1000mg daily or cyclical with fisetin
Read deeper → Longevity Stack
R
R
10 terms
Reactive Oxygen Species (ROS) Free radicals Aging
Highly reactive oxygen-containing molecules generated by mitochondria. Necessary in small amounts (signal for adaptation), damaging in excess. Hormetic — moderate exercise creates beneficial ROS exposure.
Normal Range
Balance via training, antioxidants, sleep
Read deeper → Zone 2 Cardio
Resting Heart Rate (RHR) Pulse at rest Cardiovascular
Heart rate during deep rest. One of the simplest and most predictive longevity biomarkers. Lower (within reason) is better.
Normal Range
Adult avg 70-75 bpm; healthy 55-70; athletic 45-55; elite endurance <45
Read deeper → WHOOP vs Oura
rMSSD Root Mean Square of Successive Differences Cardiovascular
The specific HRV calculation used by most wearables. Measures beat-to-beat variability that reflects parasympathetic activity. The "WHOOP HRV" number is rMSSD.
Normal Range
See HRV — same ranges apply
Read deeper → HRV Guide
Retatrutide Triple agonist Peptides
A GLP-1/GIP/glucagon triple agonist by Eli Lilly. Phase 3 trials show ~24% weight loss — the most powerful weight loss medication yet developed. Likely approval 2025-2026.
Normal Range
Investigational; not yet approved
Read deeper → Longevity Stack
Rapamycin Sirolimus Pharmaceuticals
An mTOR inhibitor and the most consistently life-extending drug in mammals. Off-label use for longevity is growing rapidly. Dosed weekly to balance benefits and side effects.
Normal Range
5-6mg weekly (off-label longevity dose); Rx
Read deeper → Longevity Stack
Red Light Therapy Photobiomodulation, PBM Recovery
Exposure to red and near-infrared light (~660nm and ~850nm). Evidence for skin health, muscle recovery, joint pain, and modest cognitive benefits.
Normal Range
10-20 min sessions, 3-5x/week
Read deeper → Longevity Stack
REM Sleep Rapid Eye Movement Sleep
The dream stage of sleep. Critical for emotional regulation, memory consolidation, and creativity. Concentrated in the second half of the night. Disrupted by alcohol.
Normal Range
20-25% of total sleep time, ~90-110 min in a 7-8h night
Read deeper → Sleep Rules
Resveratrol Red wine compound Supplements
A sirtuin-activating compound from red wine and Japanese knotweed. The hype outpaced the evidence, but it remains a reasonable longevity adjunct.
Normal Range
500mg daily with fat for absorption
Read deeper → Longevity Stack
RER (Respiratory Exchange Ratio) VCO2/VO2 Training
The ratio of CO2 produced to O2 consumed. Reflects fuel use — 0.7 = pure fat, 1.0 = pure carbohydrate.
Normal Range
Lower RER at given intensity = better metabolic flexibility
Read deeper → Zone 2 Cardio
RIR / RPE Reps in Reserve / Rate of Perceived Exertion Training
Subjective intensity measures. RIR = how many more reps you could do; RPE = 1-10 scale of effort. Modern programming uses these instead of %1RM.
Normal Range
Most hypertrophy work at RIR 1-3 (RPE 7-9)
Read deeper → Strength Training
S
S
19 terms
Senolytics Senescent cell clearance Aging
Compounds that selectively kill senescent ("zombie") cells. Most-studied: fisetin, quercetin, dasatinib. Typically dosed cyclically (5 days/month) rather than daily.
Normal Range
Fisetin 500mg + quercetin 1000mg for 5 consecutive days/month (research protocol)
Read deeper → Longevity Stack
Sirtuins SIRT1-7 Aging
A family of 7 enzymes regulating DNA repair, mitochondrial function, and inflammation. Activated by NAD+, caloric restriction, exercise. Inhibited by chronic high blood sugar.
Normal Range
Boosted via NAD+ precursors, exercise, fasting
Read deeper → NAD/NMN/NR Guide
Sarcopenia Age-related muscle loss Body Comp
The progressive loss of muscle mass and strength with age. Begins as early as the 30s; accelerates after 50. The single biggest reversible threat to healthy aging.
Normal Range
~3-8% muscle loss per decade after 30 if not training
Read deeper → Protein for Longevity
Skeletal Muscle Index (SMI) Appendicular lean mass / height² Body Comp
A standardized measure of muscle mass relative to height. Used to diagnose sarcopenia clinically. Below cutoff = sarcopenic.
Normal Range
Males <7.0 kg/m²; Females <5.4 kg/m² = sarcopenia threshold
Read deeper → Protein for Longevity
SDNN Standard Deviation of NN Intervals Cardiovascular
An alternative HRV calculation reflecting overall autonomic activity over longer windows (5+ minutes). Used by Apple Watch and some others. Not directly comparable to rMSSD.
Normal Range
Adult average 50-100ms; athletic 100-150ms+
Read deeper → HRV Guide
Stroke Volume Blood per beat Cardiovascular
The volume of blood pumped per heartbeat. Larger stroke volume = more cardiovascular efficiency. Endurance training increases stroke volume dramatically (sometimes called "athletic heart").
Normal Range
~70mL at rest; up to 200mL in trained athletes
Read deeper → Zone 2 Cardio
SHBG Sex Hormone Binding Globulin Hormones
A protein that binds testosterone and estradiol, reducing their bioavailability. High SHBG can mask low free testosterone despite normal total T.
Normal Range
Adult male 16.5-55.9 nmol/L; female 24.6-122
Read deeper → Blood Tests
Sympathetic Nervous System Fight-or-Flight Nervous System
The "action" arm of the autonomic nervous system. Activated during stress, exercise, and excitement. Chronic dominance suppresses HRV and harms recovery.
Normal Range
Activated short-term is healthy; chronic is harmful
Read deeper → Meditation Effect
Selank Anxiolytic peptide Peptides
A Russian anxiolytic peptide with mild cognitive enhancement. Limited Western research, popular in biohacker circles.
Normal Range
Nasal spray; off-label
Read deeper → Longevity Stack
Semaglutide Ozempic, Wegovy Peptides
A GLP-1 receptor agonist for type 2 diabetes and obesity. ~15% average weight loss in obesity trials. Recently shown to reduce cardiovascular events 20%.
Normal Range
0.25-2.4mg weekly subcutaneous (Wegovy); Rx
Read deeper → Longevity Stack
Semax Russian nootropic peptide Peptides
A Russian heptapeptide marketed as a nootropic and neuroprotective agent. Limited Western trials; popular in biohacking.
Normal Range
Nasal spray; off-label
Read deeper → Longevity Stack
Sermorelin GHRH analog Peptides
A growth hormone-releasing hormone analog. Older than CJC-1295 and shorter-acting. Prescribed legally in the US in some states.
Normal Range
200-500 mcg subcutaneous nightly
Read deeper → Longevity Stack
SGLT2 Inhibitors Jardiance, Farxiga Pharmaceuticals
Diabetes drugs that cause glucose excretion in urine. Strong cardiovascular and kidney protection independent of glucose effects. Likely future longevity candidates.
Normal Range
Daily oral; Rx for diabetes/heart failure
Read deeper → Blood Tests
Statins Atorvastatin, Rosuvastatin Pharmaceuticals
Class of LDL-lowering drugs. Most-studied medication in cardiovascular medicine. Modern view: nearly everyone over 50 with elevated ApoB benefits from a low-dose statin.
Normal Range
Rosuvastatin 5-20mg or Atorvastatin 10-40mg
Read deeper → Blood Tests
Sleep Architecture Sleep stages Sleep
The pattern of how sleep cycles through light, deep, and REM stages. Disrupted by alcohol, late eating, cannabis, and overheating.
Normal Range
4-6 cycles per night, ~90-110 min each
Read deeper → Evening Routine
Sleep Debt Accumulated sleep deficit Sleep
The cumulative difference between sleep needed and sleep obtained. You cannot fully "catch up" on weekends. Chronic sleep debt drives every metric of health downward.
Normal Range
2-3 nights of normal sleep recovers acute debt
Read deeper → Sleep Rules
Sleep Efficiency Sleep quality % Sleep
The percentage of time in bed actually asleep. Time Asleep ÷ Time In Bed × 100.
Normal Range
85-90% healthy; >92% excellent; <80% problematic
Read deeper → Bedtime Protocol
Sleep Latency Sleep onset Sleep
The time it takes to fall asleep after lights out. Both extremes are problematic.
Normal Range
10-20 minutes is healthy
Read deeper → Evening Routine
Spermidine Autophagy supplement Supplements
A polyamine that induces autophagy. Found naturally in wheat germ, aged cheese, mushrooms. Emerging longevity supplement.
Normal Range
1-2mg daily; or via diet
Read deeper → Longevity Stack
T
T
14 terms
Telomeres Chromosome caps Aging
Protective DNA-protein structures at the ends of chromosomes. Shorten with each cell division and act as a biological aging clock. Lengthened modestly by exercise, meditation, and certain interventions.
Normal Range
Length measured via blood test (LCT, TruDiagnostic, others)
Read deeper → Biological Age Drop
Telomerase TERT enzyme Aging
The enzyme that maintains telomere length. Active in stem cells and immune cells, mostly inactive in adult somatic cells. TA-65 and similar supplements aim to activate it modestly.
Normal Range
Subject of intense longevity research
Read deeper → Longevity Stack
Time-Restricted Eating (TRE) See Intermittent Fasting Diet
See Intermittent Fasting. Eating within a defined window (e.g. 12pm-8pm) and fasting the rest.
Normal Range
8-10 hour eating window is most studied
Read deeper → Morning Routine
Testosterone (Total) T Hormones
The primary androgen in males (also present in females). Drives muscle mass, libido, mood, cognition, and energy. Declines ~1% per year after 30.
Normal Range
Males adult range 264-916 ng/dL; optimal 500-900
Read deeper → Blood Tests
Thyroid Panel TSH, Free T4, Free T3, Reverse T3 Hormones
Comprehensive thyroid assessment. TSH alone is insufficient. Free T3 is the active form; reverse T3 elevation indicates stress/conversion issues. Antibodies (TPO, TG) screen for autoimmune thyroid.
Normal Range
TSH 0.4-4.0 mIU/L; optimal 1.0-2.0. Free T3 2.0-4.4 pg/mL
Read deeper → Blood Tests
TRT (Testosterone Replacement Therapy) Exogenous T Hormones
Medical replacement of testosterone in hypogonadal men. Standard protocols: testosterone cypionate injections weekly (or 2x/week), gels, or pellets. Requires monitoring of estradiol, hematocrit, PSA.
Normal Range
Indicated for total T <300 ng/dL with symptoms; specialist supervision required
Read deeper → Blood Tests
TNF-α Tumor Necrosis Factor alpha Inflammation
A pro-inflammatory cytokine central to chronic inflammation. Elevated in autoimmune disease, metabolic syndrome, and inflammaging.
Normal Range
<8.1 pg/mL in healthy adults
Read deeper → Blood Tests
Triglycerides TG Lipid
Blood fats reflecting recent carbohydrate intake and metabolic health. High TG with low HDL is the most telling pattern for metabolic syndrome.
Normal Range
Optimal <80 mg/dL; <150 normal; >200 elevated
Read deeper → Blood Tests
TB-500 Thymosin Beta-4 Peptides
A peptide promoting tissue repair and reduced inflammation. Used for soft tissue healing. Banned by WADA.
Normal Range
Off-label; 2-5mg subcutaneous weekly
Read deeper → Longevity Stack
Tesamorelin Egrifta Peptides
A GHRH analog FDA-approved for reducing visceral fat in HIV-associated lipodystrophy. Off-label use for visceral fat reduction in non-HIV adults.
Normal Range
2mg daily subcutaneous; Rx
Read deeper → Longevity Stack
Thymosin Alpha-1 Tα1 Peptides
An immune-modulating peptide. Approved for hepatitis B in some countries; used off-label for immune support and post-viral recovery.
Normal Range
1.6mg subcutaneous 2x/week (off-label)
Read deeper → Longevity Stack
Tirzepatide Mounjaro, Zepbound Peptides
A dual GLP-1/GIP agonist by Eli Lilly. ~20% average weight loss in obesity trials — more powerful than semaglutide. FDA-approved for diabetes and obesity.
Normal Range
2.5-15mg weekly subcutaneous; Rx
Read deeper → Longevity Stack
Thermal Stress Heat shock / cold shock Recovery
Exposing the body to extreme temperatures (sauna or cold plunge) to trigger adaptive responses. Sauna 4x/week 20+ min reduces all-cause mortality 40% in Finnish studies.
Normal Range
Sauna 4x/week, cold plunge 3x/week (morning)
Read deeper → Sauna and Cold
TUDCA Tauroursodeoxycholic acid Supplements
A bile acid that supports liver and mitochondrial health. Popular as a liver-protective add-on to TRT or other liver-stressing protocols.
Normal Range
250-500mg daily
Read deeper → Longevity Stack
U
U
1 term
Urolithin A Mitopure Supplements
A microbial metabolite of ellagic acid that induces mitophagy. Strong mechanistic data; emerging human evidence.
Normal Range
500-1000mg daily (Timeline Mitopure)
Read deeper → Longevity Stack
V
V
6 terms
Visceral Fat Belly fat (deep) Body Comp
Fat stored around organs in the abdomen. The most metabolically dangerous fat depot — drives insulin resistance, cardiovascular disease, and inflammation. Measured via DEXA.
Normal Range
Healthy <1 lb; concerning >2 lbs (DEXA scale)
Read deeper → Protein Experiment
VO2 Max Maximum oxygen consumption Cardiovascular
The peak rate the body can use oxygen during exercise. The strongest single predictor of all-cause mortality. Improvable at any age via Zone 2 + interval training.
Normal Range
Males 30-35: 35 sedentary, 42 average, 48 active, 55+ athletic. -5 for females. -3 per decade after 30
Read deeper → Zone 2 Cardio
VO2 Max Test Maximal exercise test Diagnostics
A clinical test measuring peak oxygen uptake on a treadmill or bike with a mask. The only way to accurately measure VO2 Max. Wearable estimates are useful but ~10-15% off true value.
Normal Range
$150-300 at sports performance labs
Read deeper → Zone 2 Cardio
Vagus Nerve CN X Nervous System
The 10th cranial nerve and the longest in the body. Carries 75% of parasympathetic signals. Stimulated by deep breathing, cold exposure, humming, gargling, meditation.
Normal Range
Vagal tone reflected in HRV
Read deeper → Cold Plunge Data
Vitamin D3 Cholecalciferol Supplements
Essential fat-soluble vitamin. Most adults are deficient. Co-supplement with K2 (MK-7) to prevent arterial calcification.
Normal Range
2000-5000 IU daily; aim for blood 25(OH)D 40-60 ng/mL
Read deeper → Longevity Stack
Vitamin K2 (MK-7) Menaquinone-7 Supplements
A vitamin that directs calcium away from arteries into bones. Critical co-factor with Vitamin D and calcium supplementation.
Normal Range
90-200 mcg daily
Read deeper → Longevity Stack
W
W
2 terms
Waist-to-Hip Ratio (WHR) WHR Body Comp
A simple measure of fat distribution. Better predictor of cardiovascular risk than BMI. Apple shape (high WHR) = elevated risk; pear shape = protective.
Normal Range
Optimal males <0.90; females <0.85
Read deeper → Biological Age Drop
Wim Hof Method WHM Recovery
A combination of breathing technique, cold exposure, and mindset. Some validated effects on inflammation and stress resilience. Don't do the breathing in water.
Normal Range
Daily breathing protocol; cold exposure 2-5x/week
Read deeper → Cold Plunge Data
Z
Z
1 term
Zone 2 Cardio Easy aerobic Training
Steady-state cardio at ~60-70% of max heart rate — the intensity where you can hold a conversation. Builds mitochondrial density and aerobic capacity better than higher intensities.
Normal Range
180-200 min/week for serious metabolic adaptation
Read deeper → Zone 2 Cardio