When people who aren't exercising get leucine (a type of BCAA) through an IV, it activates a protein (p70 S6 kinase) that helps build muscle, and it does this without using the Akt pathway.
Scientific Claim
Leucine infusion increases p70 S6 kinase phosphorylation in an Akt-independent manner in resting human subjects, which may represent a distinct mechanism for protein synthesis activation.
Source Excerpt
“It has previously been shown that leucine infusion increases p70 S6 kinase phosphorylation in an Akt-independent manner in resting subjects; however, a relation between mTOR and p70 S6 kinase has not been reported previously.”
Evidence from Studies
Supporting Studies
Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise.
The study references prior research showing leucine increases p70 S6 kinase phosphorylation independently of Akt in resting subjects. This is a mechanistic finding about how leucine might work in non-exercising conditions.
⚠️ Overstated
The study is referencing prior research, not conducting new experiments on leucine infusion. The claim uses 'increases' which implies causation, but the original study design for this finding is unclear.
More accurate phrasing:
“Leucine infusion is associated with increased p70 S6 kinase phosphorylation in an Akt-independent manner in resting human subjects, which may represent a distinct mechanism for protein synthesis activation.”