Body muscle building supplements are dietary supplements commonly used by those involved in body muscle building, weightlifting, mixed martial arts, and athletics for the purpose of facilitating an increase in lean body mass. The intent is to increase muscle, increase body weight, improve athletic performance, and for some sports, to simultaneously decrease percent body fat so as to create better muscle definition. Among the most widely used are high protein drinks, pre-workout blends, branched-chain amino acids (BCAA), glutamine, arginine, essential fatty acids, creatine, HMB, whey protein, ZMA and weight loss products like oil injections and oral gears for bulk or shred. Supplements are sold either as single ingredient preparations or in the form of "stacks" - proprietary blends of various supplements marketed as offering synergistic advantages. While many body muscle building supplements are also consumed by the general public the frequency of use will differ when used specifically by body muscle builders. One meta-analysis concluded that - for athletes participating in resistance exercise training and consuming protein supplements for an average of 13 weeks - total protein intake up to 1.6 g/kg of body weight per day would result in an increase in strength and fat-free mass, but that higher intakes would not further contribute.