A combined 30 g of whey protein and 10 g of collagen a day added more muscle than whey alone. An 8-week randomized, double-blind, placebo-controlled trial in resistance-trained men, published in BMC Sports Science, Medicine & Rehabilitation, screened 52 men and enrolled 40 resistance-trained men, split into four groups — whey protein plus collagen (30 g whey + 10 g collagen/day), whey protein alone (30 g/day), collagen alone (10 g/day), or a maltodextrin placebo (10 g/day) — while all four groups followed the same supervised resistance-training program, three sessions a week.
Muscle mass grew the most in the combined group. Over 8 weeks: the whey+collagen group gained 2.66 kg of muscle mass, versus 1.59 kg with whey alone, 0.46 kg with collagen alone, and 0.10 kg with placebo (p<0.001 between groups).
Bone density moved too — but only in two of the four groups. Lumbar spine bone mineral density rose significantly in the whey+collagen group (Δ = 0.108 ± 0.027 g/cm²) and, to a smaller degree, in the collagen-only group (Δ = 0.023 ± 0.018 g/cm²). Whey alone and placebo showed no significant change in bone density, which suggests collagen — not whey — is doing the bone-related work.
Strength followed the same pattern. The combined group also had the largest strength gains, adding 15.22 kg to the squat and 10.63 kg to the bench press, ahead of both single-supplement groups.
A caveat worth stating plainly. Each of the four groups had only 10 men — a small number for drawing firm conclusions, even though the between-group differences were statistically significant. The authors declared no conflicts of interest.
Who this applies to. Every participant was already a resistance-trained man following a supervised program; the trial says nothing about untrained people or women.
Bottom line. Adding 10 g of collagen to a 30 g daily whey protein dose was linked to more muscle gain, more bone density gain, and more strength gain over 8 weeks than whey alone — in a small but well-controlled trial of resistance-trained men.
Medical note. This article is intended for general educational purposes and should not be considered personal medical advice.