When people do weightlifting and then take BCAAs, their muscles show signs of activity in pathways that help build protein, which might help muscles recover and grow.
Scientific Claim
Branched-chain amino acids (BCAAs) are associated with increased phosphorylation of mTOR and p70 S6 kinase in human skeletal muscle during recovery from resistance exercise, suggesting a potential role in activating protein synthesis pathways.
Source Excerpt
“When BCAAs were supplied to subjects during and after one session of quadriceps muscle resistance exercise, an increase in mTOR, p70 S6 kinase, and S6 phosphorylation was found in the recovery period after the exercise with no effect of BCAAs on Akt or glycogen synthase kinase 3 (GSK-3) phosphorylation.”
Evidence from Studies
Supporting Studies
Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise.
The study observed increased phosphorylation of mTOR and p70 S6 kinase in response to BCAA supplementation during recovery from resistance exercise. This is a mechanistic finding showing activation of protein synthesis pathways, though the study design does not establish causation.
⚠️ Overstated
The study design is unclear (Level 5 evidence), and the claim uses 'associated with' which is appropriate, but the phrase 'suggesting a potential role' is still somewhat causal. The study only shows correlation, not causation.
More accurate phrasing:
“Branched-chain amino acids (BCAAs) are associated with increased phosphorylation of mTOR and p70 S6 kinase in human skeletal muscle during recovery from resistance exercise, indicating a possible link to protein synthesis pathway activation.”