BCAAs might help muscles build protein after exercise by turning on mTOR and p70 S6 kinase, but they don't seem to work through GSK-3.
Scientific Claim
BCAAs may activate mTOR and p70 S6 kinase in human muscle during recovery from exercise, while GSK-3 does not appear to be involved in BCAA-mediated anabolic effects on human muscle.
Source Excerpt
“The results suggest that BCAAs activate mTOR and p70 S6 kinase in human muscle in the recovery period after exercise and that GSK-3 is not involved in the anabolic action of BCAAs on human muscle.”
Evidence from Studies
Supporting Studies
Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise.
The study's conclusion states that BCAAs activate mTOR and p70 S6 kinase during recovery from exercise, and GSK-3 is not involved. This is a mechanistic interpretation of the findings.
⚠️ Overstated
The study design is unclear (Level 5 evidence), and the claim uses 'activate' and 'is not involved' which implies causation. The study only shows association, not causation.
More accurate phrasing:
“BCAAs are associated with activation of mTOR and p70 S6 kinase in human muscle during recovery from exercise, and GSK-3 does not appear to be associated with BCAA-mediated anabolic effects on human muscle.”