Protein

For muscle-building programs, trials tested supplemental protein amounts from 10 to 80 g per day alongside resistance training. The better-supported use is adding protein to an already consistent training and eating routine, where meta-analyses show modest additional gains in lean mass and strength. 1 2 Strength-focused research also tested 600 mg/kg/day over 6 weeks, though your useful amount depends on how much protein meals already provide. 1

Use protein on training days and rest days alike, since muscle rebuilding continues between sessions. Research supporting strength and muscle gains used regular intake across multiweek training plans, rather than occasional shakes after a hard workout. 1 2 Put it wherever it fits your routine, such as after training or with a meal you usually find low in protein.

The strongest trial coverage evaluates supplemental protein alongside resistance training, including dairy-based proteins and mixed protein supplements. 1 2 Choose a product that clearly lists grams of protein per serving and its source, such as whey, casein, soy, or a blended plant protein. The label matters more than marketing language about proprietary muscle formulas.

Protein is a nutrient made from amino acids, the small parts your body uses to build and repair tissue. You get it from foods such as dairy, eggs, meat, soy, beans, and grains, while powders offer a convenient concentrated option. 2

Resistance exercise tells muscle to remodel itself, and protein supplies the amino acids for that job. Think of training as issuing a construction permit and dietary protein as delivering the bricks: without enough bricks, the rebuild has less to work with. After exercise, protein intake increases the process that assembles new muscle proteins. 3