Applied Nutrition Critical Mass Lean Mass Gainz is one of the top weight gain supplements available. It features a powerful formula that stands out from other products designed to help you gain weight and build muscle. Each serving provides 42 grams of fast- and slow-digesting protein, delivering a sustained supply of protein to support muscle growth and recovery over an extended period. Additionally, it contains a substantial amount of calories to promote both weight and muscle gain, while replenishing the body's energy levels.