The Study
Oral Branched-Chain Amino Acids Supplementation in Athletes: A Systematic Review
This study looked at lots of smaller studies about BCAA supplements and athletes. It found that BCAAs might help reduce muscle soreness after weightlifting, but they don't seem to make you stronger or faster. We can't say for sure because the original studies weren't all done very carefully.
Analysis score
Maximum 85 for a systematic review.
Where the score came from
BCAAs are amino acids in protein that some athletes take as pills to help with muscle growth and recovery, but this review looked at 24 studies to see if they actually work.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 528 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1If you're already eating enough protein (like 1.6g per kg of body weight daily), taking extra BCAAs won't give you extra muscle or strength — your body already has what it needs.
- 2BCAAs didn't help athletes get stronger, leaner, or faster.
- 3They slightly reduced muscle soreness after weightlifting but not after running or cycling.
- 4Most studies didn't track how much total protein athletes ate.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2022
Authors
D. Martinho, H. Nobari, A. Faria, Adam Field, Daniel Duarte, H. Sarmento
Related Content
Claims (6)
Most studies on branched-chain amino acid supplements for athletes do not record how much total protein the athletes consume daily. Since the muscle-building effect of leucine reaches a maximum at about 1.6 grams of protein per kilogram of body weight per day, researchers cannot determine whether any observed effects are due to the branched-chain amino acids alone.
Taking branched-chain amino acid supplements daily for 7 to 10 weeks does not improve athletic performance or body composition in trained athletes who already consume enough protein.
Branched-chain amino acid supplements reduce muscle soreness after intense resistance training in athletes who lift weights, but they do not reduce soreness in endurance athletes, and the results may be influenced by how much protein they eat.
In healthy, trained adults who already consume enough protein, taking branched-chain amino acid supplements does not lead to greater muscle growth, increased strength, or faster recovery compared to not taking them.
Supplementing with branched-chain amino acids during prolonged exercise raises the ratio of branched-chain amino acids to tryptophan in the blood, which reduces the amount of tryptophan entering the brain and lowers serotonin production, but this does not reliably lead to better endurance performance.
When athletes consume enough protein through their diet, adding branched-chain amino acid supplements does not change levels of testosterone or cortisol, or the activity of the mTORC1 signaling pathway.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.