Whey protein made muscles grow faster, but it didn’t turn on the usual ‘growth switches’ in the cells—meaning it must be working through a different, unknown way.

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Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial.

Randomized Controlled Trial

Human

2020 Mar 1

The study shows whey protein helps older women build muscle better than collagen, but it didn’t check the internal body signals (like mTOR) that might explain why—so we can’t say if the claim about those signals is right or wrong.

Source Study

Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial.

Score: 66

DOI: 10.1093/ajcn/nqz332

Similar Assertions

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.

84%

When one leg got whey protein and exercise, the other leg (which didn’t exercise) still showed similar muscle-building activity—meaning the effect was happening all over the body, not just where the exercise happened.

82%

Both types of whey protein at a higher dose activated the mTOR pathway in rats' muscles compared to no protein.

76%

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.

73%

When older women drink whey protein shakes, their muscles start repairing and growing faster—especially if they also do leg exercises—while collagen protein shakes don’t do much unless they exercise, and even then, it’s much weaker.

73%