Leucine is an essential Branched chain amino acid that is important in Muscle protein synthesis. Plant proteins contain half the amount of leucine as compared to animal proteins. Studies have shown that one needs to consume about twice as much plant protein to equal the same muscle-building effects as of whey protein. This double dose of plant protein essentially provides about 2.5 to 3g of leucine, which is the amount needed for muscle protein synthesis. A study showed that whey protein that was supplemented with Leucine showed significantly higher gain in muscle mass as compared to regular whey. That is because Leucine is a co-factor involved in MTOR pathway, that converts food protein to muscle protein. It is one of the most potent factor for muscle protein synthesis.