The Science Behind Muscle & Performance Supplements

Therapeutic dose: 3–5 g/day (maintenance) or 20 g/day for 5–7 days (loading phase)

See ranked Creatine Monohydrate products→

• ISSN Position Stand (2017) reviewed 500+ studies and concluded creatine monohydrate is the most effective ergogenic nutritional supplement for increasing high-intensity exercise capacity and lean body mass. No other supplement has this level of consensus.PubMed ↗
• 2003 meta-analysis (96 RCTs) found creatine supplementation increased lean body mass by 1.09 kg and improved strength (bench press +6.85 kg, squat +9.76 kg) during resistance training vs placebo.PubMed ↗
• 2022 umbrella review of 35 meta-analyses confirmed creatine consistently improves strength, power output, and lean mass across age groups. Benefits extend to older adults — improving lower-limb strength and functional capacity.PubMed ↗
• Mechanism: creatine increases phosphocreatine stores in muscle, enabling faster ATP regeneration during high-intensity efforts. Also increases cell hydration (osmotic effect) which may stimulate protein synthesis signaling.
• Safety: ISSN confirmed no adverse effects on kidney function, liver function, or hydration status in healthy individuals at recommended doses. Long-term safety data available up to 5 years of continuous use.

Therapeutic dose: 20–40 g/serving (1.6–2.2 g protein/kg/day total)

See ranked Whey Protein products→

• 2018 meta-analysis of 49 RCTs (1,863 participants) found protein supplementation augmented resistance training-induced gains in fat-free mass (+0.30 kg) and leg press strength. Effects were dose-dependent up to ~1.6 g/kg/day total protein.PubMed ↗
• 2015 systematic review confirmed whey protein is superior to soy and casein for acute muscle protein synthesis due to its leucine content (~10–13% by weight) and rapid absorption kinetics.PubMed ↗
• Honest limitation: protein supplementation benefits are most pronounced in individuals not already meeting protein requirements through diet. For someone consuming 1.6+ g/kg/day from food, additional whey provides diminishing returns.
• Whey contains all essential amino acids and is particularly high in leucine (~2.5 g per 25 g serving), the primary trigger for mTOR-mediated muscle protein synthesis.

Therapeutic dose: 3–6 mg/kg body weight, 30–60 minutes before exercise

See ranked Caffeine products→

• ISSN Position Stand (2021) on caffeine and exercise performance reviewed extensive evidence and confirmed caffeine enhances muscular endurance, strength, power, and anaerobic performance.PubMed ↗
• 2018 meta-analysis of 10 RCTs found caffeine ingestion significantly increased maximal voluntary contraction force and muscular endurance, with a mean improvement of ~6–7% in strength performance.PubMed ↗
• Mechanism: adenosine receptor antagonism reduces perceived exertion and increases motor unit recruitment. Also enhances calcium release from the sarcoplasmic reticulum, directly improving muscle contractile force.
• Important: habitual caffeine consumers develop partial tolerance. Effects are most pronounced in non-habitual users or after caffeine washout. Individual variation in CYP1A2 metabolism means some people are fast metabolizers (benefit) vs slow metabolizers (less benefit, more side effects).

Therapeutic dose: 3 g/day (as calcium HMB or free acid form)

See ranked HMB (Beta-Hydroxy Beta-Methylbutyrate) products→

• Nissen & Sharp (2003) meta-analysis of 9 RCTs found HMB supplementation (3 g/day) increased lean mass gains by 0.28 kg and strength by 1.4% per week during resistance training.PubMed ↗
• 2015 systematic review of 7 RCTs found HMB most effective in untrained individuals and older adults beginning resistance training. Benefits in trained athletes were minimal or absent.PubMed ↗
• HMB is a leucine metabolite (~5% of leucine is converted to HMB). Anti-catabolic mechanism: reduces muscle protein breakdown via ubiquitin-proteasome pathway inhibition. More useful for preventing muscle loss than building new muscle in trained populations.
• Honest limitation: some highly positive HMB studies (Wilson et al. 2014) reported implausibly large effects and have been questioned by the scientific community. The average benefit in trained athletes is likely small to negligible.

Therapeutic dose: 2.5–5 g leucine/serving; BCAAs typically dosed at 5–10 g (2:1:1 ratio)

See ranked L-Leucine / BCAAs products→

• 2017 meta-analysis found BCAA supplementation reduced exercise-induced muscle damage (lower CK levels) and delayed-onset muscle soreness, particularly when taken before resistance exercise.PubMed ↗
• Leucine is the primary activator of the mTOR pathway — the master regulator of muscle protein synthesis. A leucine threshold of ~2–3 g per meal is required for maximal MPS stimulation.
• Critical nuance: a 2017 study showed BCAAs alone (without other essential amino acids) cannot sustain muscle protein synthesis — they only stimulate it transiently. Whole protein sources (whey, food) are superior because they provide all EAAs needed for actual muscle building.PubMed ↗
• BCAAs may have a niche use case: during fasted training or when total protein intake is very low. For anyone consuming adequate protein (1.6+ g/kg/day), BCAA supplementation is likely redundant.

Therapeutic dose: 6–8 g/day (L-citrulline) or 8–10 g/day (citrulline malate 2:1)

See ranked L-Citrulline products→

• 2019 meta-analysis of 12 RCTs found citrulline supplementation significantly improved high-intensity strength and power exercise performance, with greater effects at doses ≥6 g.PubMed ↗
• 2010 RCT found citrulline malate 8 g increased repetitions to failure by 52.92% across 8 sets of bench press and significantly reduced muscle soreness at 24 and 48 hours post-exercise.PubMed ↗
• Mechanism: L-citrulline is converted to L-arginine in the kidneys, raising plasma arginine more effectively than direct arginine supplementation (which undergoes significant first-pass hepatic metabolism). Increased arginine drives nitric oxide production, improving blood flow to working muscles.

Therapeutic dose: 3.2–6.4 g/day (divided doses to avoid paresthesia)

• Hobson et al. (2012) meta-analysis of 15 RCTs found beta-alanine supplementation significantly improved exercise performance for efforts lasting 60–240 seconds. No significant effect on efforts <60 seconds (too short) or >240 seconds (not limited by acidosis).PubMed ↗
• ISSN Position Stand (2015) confirmed beta-alanine improves exercise capacity in the 1–4 minute range and may attenuate neuromuscular fatigue during high-intensity training.PubMed ↗
• Mechanism: beta-alanine increases intramuscular carnosine concentration, which buffers H+ ions during high-intensity exercise. Carnosine loading requires 2–4 weeks of daily supplementation before performance benefits manifest.
• Limitation: paresthesia (tingling) is a common side effect at doses >800 mg in a single serving. Efficacy is specific to glycolytic exercise lasting 1–4 minutes — limited benefit for pure strength or endurance.

Therapeutic dose: 1,000–4,000 IU/day (25–100 mcg)

See ranked Vitamin D products→

• 2019 meta-analysis found vitamin D supplementation improved muscle strength in adults with baseline deficiency (<30 nmol/L), but had no significant effect on strength in vitamin D-replete individuals.PubMed ↗
• Vitamin D receptors (VDR) are expressed in skeletal muscle. Deficiency is associated with type II muscle fiber atrophy, impaired calcium handling, and proximal muscle weakness — particularly in older adults.
• Deficiency prevalence is ~42% in US adults and higher in athletes training indoors, dark-skinned individuals, and those at northern latitudes. Correcting deficiency restores muscle function; supplementing beyond sufficiency does not enhance it.

Therapeutic dose: 15 g/day (with 50 mg vitamin C, 30–60 minutes before exercise for tendon/ligament)

See ranked Collagen Peptides products→

• 2017 RCT (Keith Baar lab) showed 15 g collagen + vitamin C taken 1 hour before exercise doubled collagen synthesis markers in engineered ligaments. This targeted tendon/ligament support, not muscle protein synthesis.PubMed ↗
• 2019 RCT (24 recreationally active men) found 15 g collagen peptides during 12 weeks of resistance training increased fat-free mass and muscle strength more than placebo, though the mechanism is debated.PubMed ↗
• Honest limitation: collagen is an incomplete protein (lacks tryptophan, low in leucine). It should not replace whey or complete proteins for muscle building. Its niche is connective tissue support — tendons, ligaments, cartilage — in athletes at risk of overuse injuries.

Therapeutic dose: 200–400 mg/day elemental magnesium

See ranked Magnesium (for Muscle) products→

• Magnesium is required for >300 enzymatic reactions including ATP metabolism, muscle contraction, and protein synthesis. Deficiency impairs exercise performance and increases muscle cramps.
• 2017 systematic review found magnesium supplementation may improve exercise performance in magnesium-deficient individuals, but evidence of ergogenic benefit in replete athletes is inconsistent.PubMed ↗
• ~50% of US adults have inadequate magnesium intake. Correcting deficiency may improve muscle function, but supplementation in non-deficient individuals is unlikely to enhance muscle growth or strength beyond baseline.

Therapeutic dose: 1,000–3,000 mg/day

See ranked Taurine products→

• 2018 meta-analysis of 10 studies found taurine supplementation improved endurance exercise performance (time to exhaustion), but effects on strength and muscle mass were not significant.PubMed ↗
• Taurine is the most abundant free amino acid in skeletal muscle. It functions as an osmolyte (cell volume regulation) and modulates calcium handling in muscle fibers. However, supplementation has not been shown to increase intramuscular taurine above normal levels.
• Limitation: most taurine research is in endurance contexts or combined with caffeine (energy drinks), making it difficult to isolate muscle-specific effects.

Therapeutic dose: 2,500 mg/day

• 2013 RCT (23 trained men) found 6 weeks of betaine supplementation (2.5 g/day) improved body composition (reduced fat mass, increased lean mass) during a resistance training program.PubMed ↗
• Mechanism: betaine is an osmolyte that increases intracellular hydration and a methyl donor in homocysteine metabolism. May support creatine synthesis indirectly.
• Honest limitation: studies are few, small (typically n=12–25), and from a limited number of research groups. No meta-analysis or large-scale RCT has confirmed betaine's efficacy for muscle building. Results are inconsistent across trials.

Therapeutic dose: 2,000–4,000 mg combined EPA/DHA

• 2016 RCT by Smith et al. found 4 g/day fish oil for 8 weeks augmented muscle protein synthesis response to amino acid infusion in older adults, suggesting omega-3s may sensitize muscle to anabolic stimuli.PubMed ↗
• 2020 meta-analysis of 10 RCTs found omega-3 supplementation did not significantly improve muscle strength or lean mass in healthy adults. Benefits were limited to older adults with sarcopenia risk.PubMed ↗
• Anti-inflammatory effects may support recovery from exercise-induced muscle damage, but this does not translate to greater hypertrophy. Omega-3s are valuable for general health but should not be positioned as a muscle-building supplement.