Doing leg exercises helps whey protein build muscle even more—but even with exercise, collagen protein still can’t match whey’s muscle-building power.

With collagen protein, the muscle-building effect was almost identical in the exercised and non-exercised leg—unlike whey, which responded more strongly where exercise happened.

After drinking whey protein shakes every day for a week, older women’s muscles kept building up new protein even on days they didn’t exercise—collagen protein didn’t do this at all.

Even though whey protein made muscles build faster, it didn’t change the usual ‘on/off’ switches in muscle cells that are supposed to control growth—suggesting other mechanisms are at play.

Even though collagen protein is made of collagen, drinking it didn’t make the connective tissue inside muscles grow faster—even when combined with exercise.

For middle-aged men doing strength training, whey protein and this collagen supplement have similar effects on muscle gain and fat loss.