The Claim

Adding 4.2 grams of leucine to a protein drink containing 10 grams of protein and 24 grams of carbohydrates significantly increases myofibrillar muscle protein synthesis rates over four hours post-resistance exercise in healthy young and older men.

Source: Enriching a protein drink with leucine augments muscle protein synthesis after resistance exercise in young and older men.

What the research says

Supports is higher

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

Supports
46score
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.

Cause and effect
1 study reviewed
In plain English

When healthy young and older men consume a drink with 10 grams of protein, 24 grams of carbohydrates, and 4.2 grams of leucine after resistance exercise, their muscle protein synthesis rates increase significantly over the next four hours compared to the same drink without leucine.

See the scientific wording

Adding 4.2 grams of leucine to a protein drink containing 10 grams of protein and 24 grams of carbohydrates significantly increases muscle protein synthesis rates after resistance exercise in healthy young and older men, as measured by myofibrillar protein synthesis over four hours post-exercise.

Why this might work

After exercise, leucine from the drink enters muscle cells and triggers a molecular switch that turns on protein building. This switch activates a chain of signals that tells the cell's protein-making machines to work faster, leading to more muscle proteins being made from amino acids.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Enriching a protein drink with leucine augments muscle protein synthesis after resistance exercise in young and older men.

    Adding 4.2 grams of leucine to a protein drink after a workout helped both young and older men build muscle faster than when they drank the same drink with a different amino acid instead. Leucine acted like a signal to turn on muscle repair.

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.