Supplements marketed to boost muscle gain are typically purported to accomplish this feat when combined with a resistance-exercise program. A supplement may support muscle gain by stimulating muscle protein synthesis, improving resistance exercise performance (via enhancing force production or muscular endurance), or supporting recovery (via attenuating muscle damage).
Creatine monohydrate is by far the most effective supplement to enhance muscle gain.[1] Other popular options include caffeine, beta-alanine, ashwagandha, betaine, citrulline, HMB, alpha-GPC, taurine, branched-chain amino acids, and nitrate.