Collagen Peptide Supplementation during Training Does Not Further Increase Connective Tissue Protein Synthesis Rates

Kirmse M, Lottmann TM, Volk NR, DE Marées M, Holwerda AM, VAN Loon LJC, Platen P · Medicine and Science in Sports and Exercise

The only randomized trial to test 30 g/day of collagen peptides in a split twice-daily schedule, measured with deuterated water and muscle biopsies. Absorption worked: post-absorptive plasma glycine, proline and hydroxyproline all rose above placebo. Synthesis did not follow. Muscle connective protein synthesis was 1.97%/day on collagen against 2.00%/day on placebo, and myofibrillar synthesis 1.34% against 1.34% — identical to two decimal places.

Population

Young recreationally active men performing one week of intense resistance-type exercise training

Intervention

15 g hydrolyzed collagen peptides TWICE daily — 30 g/day — for one week

Comparator

Non-caloric placebo, same training

Limitations

One week, 25 young men, and the tissue is skeletal-muscle connective tissue rather than tendon or cartilage — a tracer study cannot biopsy articular cartilage. Independent: Ruhr-University Bochum with the Maastricht tracer group, no manufacturer in the author list.