The Claim

In neonatal pigs, a 24-hour intravenous infusion of leucine at 400 μmol/kg/h increases phosphorylation of mTOR pathway proteins 4E-BP1 and S6K1 in gastrocnemius muscle, masseter muscle, liver, and pancreas, but only stimulates protein synthesis in these tissues when concurrent amino acid infusion maintains baseline circulating amino acid levels.

Source: Differential effects of long-term leucine infusion on tissue protein synthesis in neonatal pigs

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
14score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

In neonatal pigs, a continuous intravenous infusion of leucine at 400 μmol/kg/h increases activation markers of the mTOR pathway in muscle, liver, and pancreas, but only increases protein synthesis in these tissues when amino acids are simultaneously infused to maintain normal blood levels.

See the scientific wording

In neonatal pigs, a 24-hour intravenous infusion of leucine at 400 μmol/kg/h increases phosphorylation of mTOR pathway proteins 4E-BP1 and S6K1 in gastrocnemius muscle, masseter muscle, liver, and pancreas, but only stimulates protein synthesis in these tissues when concurrent amino acid infusion maintains baseline circulating amino acid levels, indicating that leucine activates translation initiation machinery independently of substrate availability but requires amino acid sufficiency to drive actual protein synthesis.

Why this might work

Leucine turns on a molecular switch that tells cells to start making proteins, but the cells can only actually build new proteins if they have enough of all the building blocks available. Without those building blocks, the switch stays on but nothing gets made.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Differential effects of long-term leucine infusion on tissue protein synthesis in neonatal pigs

    Giving lots of leucine to baby pigs turns on a protein-making switch in their muscles and organs, but they only actually make more protein if they also get other amino acids — otherwise, the switch is on but nothing gets made.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.