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.

Scientific Claim

In healthy older women, ingestion of 30 g of whey protein twice daily for 6 days increases acute muscle protein synthesis by 0.017%/h at rest and by 0.032%/h after resistance exercise, significantly more than collagen peptides, which show no significant increase at rest and only a 0.012%/h increase after exercise.

Original Statement

“Acutely, WP increased MPS by a mean ± SD 0.017 ± 0.008%/h in the feeding-only leg (Rest) and 0.032 ± 0.012%/h in the feeding plus exercise leg (Exercise) (both P < 0.01), whereas CP increased MPS only in Exercise (0.012 ± 0.013%/h) (P < 0.01) and MPS was greater in WP than CP in both the Rest and Exercise legs (P = 0.02).”

From 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.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

The randomized controlled trial design with direct measurement of MPS using gold-standard tracer methods supports definitive causal language. The effect sizes and p-values are clearly reported and statistically significant.

Evidence from Studies

Supporting (1)

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 found that whey protein helps older women build muscle faster after eating and after exercise, while collagen peptides don’t help much—so whey is the better choice for muscle growth.

Contradicting (0)

No contradicting evidence found

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

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.

91%

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.

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When rats exercised and then ate a small amount of whey protein hydrolysate, their muscles built protein faster than when they ate regular whey protein at the same dose.

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One scoop of whey protein has over five times more of the key muscle-building amino acid (leucine) than one scoop of collagen protein—even though both have the same total protein.

77%

Even though both protein shakes had the same amount of protein, the whey one made the key muscle-building amino acid (leucine) in the blood much higher than the collagen one.

76%