The Claim
In resistance-trained young men consuming 1.8 g protein per kg body weight daily, 12 weeks of twice-weekly resistance training leads to significant increases in muscle strength and size, with no difference in outcomes between those taking 10 g/day of leucine and those taking a placebo.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
If you're a young man who already lifts weights and eats enough protein, doing strength training twice a week for 12 weeks will make you stronger and build more muscle — and taking leucine supplements won't make any extra difference compared to taking a sugar pill.
See the scientific wording
In resistance-trained young men consuming 1.8 g protein per kg body weight daily, muscle strength and size increase significantly after 12 weeks of twice-weekly resistance training, regardless of whether they take 10 g/day of leucine or a placebo.
What the research says
1 studyStudy: Leucine Supplementation Has No Further Effect on Training-induced Muscle Adaptations
The study gave some guys 10 grams of leucine daily and others a fake pill, while both groups trained and ate the same amount of protein. Both groups got just as strong and muscular, so leucine didn’t help extra — which means the claim is right.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.