We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Amino acids and derivatives ranked by evidence — from performance and recovery to sleep, mood, and cognition.
Top picks: Creatine, Whey Protein, and Arginine.
Increases phosphocreatine stores for faster ATP regeneration, boosting strength, power output, and cognitive function under stress.
Complete protein with high leucine content that maximizes muscle protein synthesis — most researched protein supplement worldwide.
Primary substrate for nitric oxide production — dilates blood vessels to improve circulation, exercise performance, and cardiovascular health.
Increases muscle carnosine to buffer acid during high-intensity exercise, extending endurance for 1-4 minute efforts.
Forms a stomach gel for 6-8 hours of sustained amino acid release — ideal for overnight muscle recovery and anti-catabolism.
Concentrated in heart, brain, and muscle — best-supported for cardiovascular and metabolic health, with modest endurance benefits and emerging (mostly animal) longevity data.
Acetylated carnitine that crosses the blood-brain barrier to fuel mitochondrial energy and donate acetyl groups for acetylcholine synthesis.
Drives 100+ methylation reactions including neurotransmitter synthesis — clinically validated for depression, osteoarthritis, and liver health.
3g before bed may improve subjective sleep quality and next-day alertness in small trials — also a building block for glutathione and collagen.
The best-evidenced plant protein: a complete protein that builds muscle and strength comparably to whey in long-term resistance-training trials, plus the only protein with FDA-recognized LDL-cholesterol lowering.
Leucine, isoleucine, and valine metabolized directly in muscle tissue — support protein synthesis and reduce exercise fatigue.
Combines citrulline for nitric oxide production with malic acid for ATP synthesis — reduces fatigue and enhances exercise endurance.
Complete essential amino acid blend that maximizes muscle protein synthesis — superior to BCAAs alone.
Leucine metabolite with small benefits to muscle mass in clinical and older populations, but meta-analyses show no effect on body composition or strength in trained, healthy adults.
Amino acid that boosts nitric oxide production, improving blood flow, exercise performance, and recovery.
Primary fuel for intestinal and immune cells. Best evidence is for sickle cell disease (FDA-approved); gut, immune, and recovery benefits in healthy people are weak or unproven.
Tea-derived amino acid that boosts alpha brain waves for calm, focused alertness — synergizes with caffeine to reduce jitteriness.
Type I collagen from fish with smaller peptide size for superior absorption — proven benefits for skin hydration and wrinkle reduction.
Rate-limiting precursor to glutathione, the body's master antioxidant — supports mood, respiratory health, and liver protection.
Amino acid precursor to dopamine and norepinephrine, supporting focus and mental performance under stress.
Direct serotonin precursor that may support mood, sleep, and appetite control, but requires caution with certain medications.
Recovery-optimized form of carnitine with evidence for muscle recovery, androgen receptor upregulation, and exercise performance.
Competes with arginine to suppress cold sore outbreaks while supporting collagen synthesis, immune function, and calcium absorption.
A well-digested plant protein that supports muscle protein synthesis and recovery comparably to whey when dosed adequately — the leading vegan protein option.
Sole dietary precursor to serotonin and melatonin — supports mood regulation and natural sleep onset more gradually than 5-HTP.
Blocks protein glycation and buffers muscle pH, supporting longevity, exercise performance, and cognitive function.
Accelerates ammonia clearance through the urea cycle, reducing exercise-induced fatigue and supporting recovery during prolonged efforts.
An essential amino acid and precursor to histamine and carnosine. Its biological roles are well established, but human supplementation evidence is thin: small positive signals in atopic dermatitis and metabolic syndrome, while a controlled trial in rheumatoid arthritis was null.
An amino acid precursor to glycine and D-serine. The honest verdict: tiny RCTs hint at slowed progression in rare neurological diseases (ALS, HSAN1), but there's no evidence it helps cognition or sleep in healthy people.
A hypoallergenic plant protein with one good resistance-training trial showing body-composition and strength gains comparable to whey when dosed high — naturally lower in lysine, so often blended with pea.
Arginine metabolite that modulates NMDA receptors and nitric oxide. The honest verdict: only the neuropathic-pain claim has any human trials (two small ones), while mood, neuroprotection, and muscle-pump claims rest on animal and review work, not human evidence.
Supplemental stomach acid marketed for digestion. The honest verdict: a single small RCT shows it temporarily reacidifies the stomach, but no trials test the protein-digestion, bloating, or nutrient-absorption claims.
Inhibitory neurotransmitter that calms neural activity — may work through the gut-brain axis for acute anxiety and sleep support.
Sulfur-containing amino acid and SAMe precursor that drives methylation, detoxification, and synthesis of cysteine, taurine, and glutathione.
A high-quality complete animal protein (top-tier PDCAAS, high leucine) that supports lean mass and is notably satiating — fat- and cholesterol-free, dairy-free, but the dedicated muscle-trial evidence is modest.
An amino acid marketed as a testosterone booster. The honest verdict: randomized trials in resistance-trained men show NO testosterone or performance benefit — and higher doses may even LOWER testosterone. An early signal in untrained men did not replicate.
A whole-food plant protein that also brings fiber and omega-3 ALA, but it is the lowest-leucine, least-complete of the common protein powders — and has essentially no direct muscle-building RCTs.