Collagen peptides supplementation improves function, pain, and physical and mental outcomes in active adults

Kviatkovsky SA, Hickner RC, Cabre HE, Small SD, Ormsbee MJ · Journal of the International Society of Sports Nutrition

The only randomized comparison of two collagen doses against placebo with a knee endpoint, and the higher dose was not the better one, though the effects are narrower than the paper's title. Of the five KOOS subscales, only activities of daily living produced a significant group-by-time interaction (p=0.031), and the follow-up tests found no group changing significantly over time, the 10 g arm reaching p=0.094. KOOS pain showed nothing in the main analysis and separated only among participants exercising at least 188 min/week (p=0.037). On the general health survey the mental component favoured 10 g/day (p=0.017 against a Bonferroni threshold of 0.017, with placebo at p=0.031) and the physical component favoured 20 g/day in women only, in a subgroup of five. Nothing was ordered by dose, and the 6-month findings were gone at 9 months.

Population

Healthy middle-aged lifelong active adults with near-ceiling knee scores at entry, followed for 9 months

Intervention

10 g/day or 20 g/day collagen peptides (SOLUGEL)

Comparator

Placebo

Limitations

The study was funded by PB Leiner, part of Tessenderlo Group, which supplied the SOLUGEL collagen tested and packaged the treatments; the authors report no conflict of interest. Baseline KOOS scores sit near the top of the scale, leaving little room to improve. The paper's own limitations say the data violated normality and homogeneity of variance throughout, and that the trial was powered only on pain at 6 months, so every other comparison is underpowered. 86 enrolled and 51 chose to continue to 9 months. Findings are scattered across subgroups defined by sex and exercise volume, which multiplies the chance of a false positive.