The Claim

Leucine supplementation does not significantly increase lean body mass in healthy, trained young adults undergoing resistance training when compared to a placebo, even when the dosage of leucine is sufficient to activate mTORC1 signaling.

Source: Effects of leucine intake on muscle growth, strength, and recovery in young active adults: a systematic review of randomized controlled trials

What the research says

Supports is higher

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

Supports
20score
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

Taking leucine supplements won’t help healthy, fit young people build more muscle than taking a sugar pill, even if the supplement is strong enough to trigger a muscle-growth signal in the body.

See the scientific wording

Leucine supplementation does not significantly increase lean body mass in healthy, trained young adults undergoing resistance training when compared to placebo, even when administered in doses sufficient to activate mTORC1 signaling.

What the research says

1 study

  1. Study: Effects of leucine intake on muscle growth, strength, and recovery in young active adults: a systematic review of randomized controlled trials

    This study looked at whether taking extra leucine helps young, fit people build more muscle when they lift weights — and found it doesn’t. So the claim that leucine doesn’t help is backed up.

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.