FitProven
Fitness Claims
Request a claimCaffeine supplementation improves exercise performance
100% Strongly SupportedCaffeine is the world's most widely consumed psychoactive substance and one of the most researched ergogenic aids in sports science. The cla...
Creatine monohydrate improves strength and power output
100% Strongly SupportedCreatine monohydrate is one of the most extensively studied sports supplements. The claim is that regular creatine supplementation (typicall...
Tart cherry juice improves sleep
73.7% SupportedMontmorency tart cherries contain melatonin and tryptophan, and several small human trials report modest sleep gains: **+34 minutes of sleep...
High-dose vitamin D supplementation causes harm in healthy adults
73.3% SupportedVitamin D is fat-soluble and stored in the body, and megadose products (5,000-50,000 IU) are sold freely. The claim is that taking high dose...
Creatine is especially beneficial for women over 40 and postmenopausal women
41.1% Mixed EvidenceMarketing and much of the popular coverage of creatine now positions midlife and postmenopausal women as the group with the most to gain, ci...
Caffeine blunts creatine's ergogenic effect
35.9% Weakly SupportedA 1996 study found that men who took caffeine alongside a creatine loading phase lost creatine's performance benefit entirely, and the findi...
Turkesterone increases testosterone and builds muscle
26.9% Weakly SupportedTurkesterone is an ecdysteroid from *Ajuga turkestanica*, sold as a "natural anabolic" on the claim that it builds muscle comparably to anab...
Berberine causes meaningful weight loss
23.2% Weakly SupportedBerberine is marketed as "nature's Ozempic", which implies a weight-loss effect in the same class as a GLP-1 agonist. The meta-analytic evid...
Vitamin D supplementation improves muscle strength and athletic performance
21.4% Weakly SupportedVitamin D is widely marketed to lifters and athletes as a performance supplement, on the basis that vitamin D receptors are present in skele...
BPC-157 accelerates tendon and muscle healing in humans
19.2% Not SupportedBPC-157 ("Body Protection Compound 157") is a synthetic pentadecapeptide sold by peptide vendors and prescribed by some wellness clinics as ...
BCAA supplements are worth taking for muscle growth
0% Insufficient EvidenceBranched-chain amino acids (BCAAs — leucine, isoleucine, and valine) are widely marketed as supplements that promote muscle protein synthesi...