Vegan BRANDS of BCAA's in Health & Nutrition Programs Posted November 2, 2008 What the heck are these things and are they really necessary? Sound like a highly manufactured, man made product to me. Well, a BCAA supplement on it's own is definitely not a "naturally occuring" product. BCAAs (leucine, isoleucine, valine) are found in foods with protein. BCAA supps can be helpful for someone interested in preserving/gaining muscle mass.