UC-II Undenatured Type II Collagen for Knee Joint Flexibility: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Clinical Study

Schön C, Knaub K, Alt W, Durkee S, Saiyed Z, Juturu V · Journal of Integrative and Complementary Medicine

Active knee flexion rose 3.23 degrees against 0.21 on placebo at 24 weeks (p=0.025), and 6.79 against 0.30 in the over-35 subgroup (p=0.0092). Three other range-of-motion measures did not separate between groups: passive flexion (2.15 vs 0.06; p=0.31), extension (2.21 vs 1.27; p=0.31) and active flexion in men (1.05 vs 0.95). The extension gain the paper concludes on is a within-group change over time; the between-group test on the same measure is null. Women accounted for the flexion result (4.79 vs -0.32; p=0.0063). No pain or function outcome was reported, though a step-down pain test set eligibility.

Population

Healthy adults aged 20-55 with activity-related joint discomfort on a single-leg step-down test, no osteoarthritis

Intervention

40 mg undenatured type II collagen daily for 24 weeks

Comparator

Placebo

Limitations

Three authors are employees of Lonza Greenwood LLC, which owns UC-II. Healthy volunteers rather than osteoarthritis patients, and range of motion rather than pain or function. Randomisation was stratified by gender, not age, and the age subgroups are unevenly allocated (19 against 27 over 35, 29 against 21 under). The product is specified as providing at least 3% undenatured type II collagen, or about 1.2 mg in the 40 mg dose.