The Claim

Co-ingestion of 20 grams of protein and 3.5 grams of free leucine with carbohydrates after simulated daily activities increases muscle protein synthesis rates by approximately 35% in healthy young men (0.082%/h vs. 0.060%/h) and by 67% in healthy elderly men (0.072%/h vs. 0.043%/h) over a 6-hour period, with no statistically significant difference in response between the two age groups.

Source: Co-ingestion of protein and leucine stimulates muscle protein synthesis rates to the same extent in young and elderly lean men.

What the research says

Supports is higher

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

Supports
54score
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.

Quantitative
1 study reviewed
In plain English

Consuming 20 grams of protein and 3.5 grams of free leucine with carbohydrates after daily physical activity increases muscle protein synthesis rates by 35% in healthy young men and by 67% in healthy elderly men over six hours, with no statistically significant difference between the two age groups.

See the scientific wording

Co-ingestion of 20 grams of protein and 3.5 grams of free leucine with carbohydrates after simulated daily activities increases muscle protein synthesis rates by approximately 35% in healthy young men (0.082%/h vs. 0.060%/h) and by 67% in healthy elderly men (0.072%/h vs. 0.043%/h) over a 6-hour period, with no statistically significant difference in response between the two age groups.

Why this might work

After eating protein and leucine with carbohydrates, leucine levels in the blood rise, which turns on a cellular switch called mTORC1 in muscle cells. This switch activates machinery that reads genetic instructions to build new muscle proteins, making the muscle produce more protein faster.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Co-ingestion of protein and leucine stimulates muscle protein synthesis rates to the same extent in young and elderly lean men.

    When older and younger men drank a mix of protein, leucine, and carbs after light activity, their muscles made new protein faster than when they drank just carbs — and both age groups benefited equally. The study proves this works for both young and old.

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.