This is why it is particularly important to ensure their intake from external sources. Leucine is a branched-chain amino acid (BCAA) and is among the 9 essential amino acids. 1 Serving Daily. Made in a factory that manufactures Milk, Egg, Gluten, Soy, Peanuts, Crustaceans, Fish, Molluscs, Sulphur Dioxide and Nuts containing foods.
