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Supplements Training Longevity Health Articles & Research Calculators

Longevity Hub

Scientific
Research Library

Every claim on The Iron Verdict is sourced from peer-reviewed research. This is that source — a searchable, filterable database of landmark studies in longevity, exercise science, nutrition, and supplementation.

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Strong Multiple RCTs or large meta-analyses
Moderate RCTs with limitations or smaller samples
Emerging Early-stage human studies or promising mechanistic data
Limited Observational only or small sample size
Mixed Contradictory findings across studies
Strong Evidence 2008
Muscle & Longevity

Muscular Strength and All-Cause Mortality in Men

In 8,762 men followed 18.9 years, muscular strength was inversely associated with death from all causes and cancer independently of cardiorespiratory fitness. Low strength was the strongest predictor of early mortality.

Strong Evidence 2022
Muscle & Longevity

Muscle-Strengthening Activities and Mortality Risk

Meta-analysis of 16 prospective cohorts (n=1,777,673). Muscle-strengthening activities independently associated with 15–17% lower all-cause mortality, cardiovascular disease, and cancer mortality.

Moderate Evidence 2018
Muscle & Longevity · Supplements

Protein Supplementation and Muscle Mass: Meta-Analysis of 49 RCTs

Protein supplementation significantly augmented lean body mass (+0.30 kg) and strength. Effect was greatest in untrained individuals and older adults. Upper threshold ~1.62 g/kg/day for muscle mass gains.

Strong Evidence 2018
Cardiovascular Health

VO₂ Max and All-Cause Mortality: 122,000 Patient Study

In 122,007 patients, the highest fitness group had 5× lower mortality risk vs. the lowest. The hazard ratio from elite to low fitness exceeded that of established risk factors including smoking, hypertension, and diabetes.

Strong Evidence 2016
Cardiovascular Health

Cardiorespiratory Fitness as a Quantitative Predictor of All-Cause Mortality

CRF (measured as VO₂ max or METs) is among the strongest independent predictors of long-term mortality. Comparable in effect size to established risk factors. Evidence strongly supports CRF assessment in clinical practice.

Moderate Evidence 2019
Cardiovascular Health · Supplements

Marine Omega-3 Supplementation and Cardiovascular Mortality

Meta-analysis of 13 RCTs (n=127,477). Marine omega-3 associated with 10% reduction in cardiovascular mortality and 8% reduction in fatal MI. EPA-dominant formulations showed stronger effects.

Strong Evidence 2010
Sleep

Sleep Duration and All-Cause Mortality: Meta-Analysis (n=1,382,999)

Both short sleep (<6h) and long sleep (>9h) are independently associated with significantly higher all-cause mortality in a dose-response fashion. U-shaped relationship confirmed across 16 prospective studies.

Moderate Evidence 2012
Sleep · Supplements

Magnesium Supplementation and Insomnia in Elderly Adults

Double-blind RCT (n=46 elderly adults). 500mg magnesium/day for 8 weeks significantly improved sleep quality, ISI score, sleep efficiency, and melatonin levels vs. placebo. Subjective sleep time increased by 35 min.

Moderate Evidence 2002
Sleep · Supplements

Magnesium and Slow-Wave Sleep

Oral magnesium supplementation in young adults significantly enhanced slow-wave (deep NREM) sleep, reduced cortisol levels, and increased plasma melatonin concentrations compared to placebo.

Strong Evidence 2017
Supplements · Muscle & Longevity

Creatine Supplementation and Health Outcomes in Aging: Narrative Review

Creatine monohydrate supplementation combined with resistance training significantly improves lean body mass, strength, functional performance, bone mineral density, and cognitive function in older adults (>55 years).

Strong Evidence 2018
Supplements · Cardiovascular

Beta-Alanine Supplementation and Exercise Capacity: Meta-Analysis

Meta-analysis of 40 double-blind RCTs confirms beta-alanine improves exercise capacity for efforts of 1–10 minutes. Carnosine buffering effect reduces intramuscular acidosis and extends time-to-fatigue by 2.85%.

Moderate Evidence 2016
Supplements · Aging

Nicotinamide Riboside and NAD+ Metabolism in Humans

First-in-human RCT: NR 1,000mg/day significantly raised whole blood NAD+ by ~45% vs. baseline in healthy adults. NAD+ metabolism was dose-dependent. No serious adverse events at doses up to 1,000mg/day.

Strong Evidence 2015
Metabolic Health · Nutrition

Personalized Nutrition by Prediction of Glycemic Responses

Landmark study demonstrating that postprandial glucose responses to identical foods vary dramatically between individuals due to microbiome composition, genetics, and lifestyle. Personalized dietary interventions outperformed standard guidelines.

Moderate Evidence 2022
Metabolic Health · Biohacking

Time-Restricted Eating and Metabolic Health: RCT

16:8 time-restricted eating in adults with metabolic syndrome over 3 months significantly improved fasting glucose, insulin resistance, blood pressure, and visceral fat vs. calorie-matched controls without time restriction.

Emerging Evidence 2018
Cellular Aging

Spermidine Induces Autophagy and Extends Lifespan

Exogenous spermidine extends lifespan in yeast, flies, worms, and mice via autophagy induction. Dietary spermidine inversely associated with cardiovascular mortality in human cohort (n=829). Epigenetic anti-aging effects proposed.

Moderate Evidence 2014
Cellular Aging · Nutrition

Mediterranean Diet and Telomere Length

Greater adherence to Mediterranean diet significantly associated with longer telomere length — a marker of biological aging — in 4,676 healthy women. Each 1-SD increase in MDS score corresponded to 1.5 years less biological aging.

Moderate Evidence 2021
Biohacking

Cold Water Immersion and Muscle Recovery

Systematic review and meta-analysis: CWI significantly reduces DOMS up to 96h post-exercise and accelerates recovery of strength and power. Optimal protocol: 11–15°C for 11–15 minutes. Note: may blunt long-term hypertrophy adaptations.

Emerging Evidence 2022
Biohacking

Red Light Therapy and Mitochondrial Function

Photobiomodulation (660–850nm) stimulates cytochrome c oxidase, increasing ATP production and reducing mitochondrial ROS. Human studies show benefits for muscle recovery, cognitive performance, and wound healing. Longevity effects in humans remain speculative.

Strong Evidence 2017
Nutrition

Vitamin D₃ vs D₂ Supplementation Efficacy

D₃ is ~87% more potent than D₂ in raising and maintaining serum 25(OH)D. Deficiency (<20 ng/mL) associated with 35% higher all-cause mortality. 2,000 IU D₃/day adequate for most adults; 4,000 IU for deficient individuals.

Strong Evidence 2018
Nutrition · Muscle & Longevity

Dietary Protein and Muscle Health in Aging

Older adults require 1.0–1.2 g/kg protein/day minimum (double WHO recommendation) to maintain muscle mass. Anabolic resistance with aging requires higher leucine thresholds (~3–4g) and larger protein doses (40–50g) per meal.

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