Extra leucine let a 6.25 g whey drink match a 25 g one, in one trial
A 6.25 g whey drink topped up to 5.0 g of total leucine held muscle protein synthesis about as high as a 25 g whey drink for three hours. Eight men per arm.
What the study found
Topping a small whey drink with leucine made it act like a big one
Leucine dose, not total protein, is what moved. A 6.25 g whey drink topped up to 5.0 g of total leucine held muscle protein synthesis about as high as a 25 g whey drink for the next three hours. The same small drink at its native 0.75 g of leucine did not.
The caveat · One session, nothing on muscle size
Eight men per arm, one acute measurement, nothing past four and a half hours and nothing on muscle size. Part-funded and co-authored with a commercial protein-beverage research centre, a direct interest in a result about beverage formulation. A fifth arm added isoleucine and valine, and its value was never published.