Proline-rich peptides (PRPs) are short chains of amino acids containing high levels of the amino acid proline. They are found in various natural sources, including milk (especially colostrum) and some plant proteins. Their use for cartilage damage is supported by a modest but growing body of scientific research, primarily in preclinical (animal and in vitro) models. PRPs have been shown to have immunomodulatory and anti-inflammatory properties, which are relevant to the pathophysiology of cartilage damage and osteoarthritis.

Some studies have demonstrated that PRPs can inhibit the production of inflammatory cytokines and matrix metalloproteinases, both of which are implicated in cartilage degradation. There is also limited evidence that PRPs may stimulate chondrocyte proliferation and extracellular matrix synthesis, potentially supporting cartilage repair. However, robust clinical trials in humans specifically investigating the effects of PRPs on cartilage damage or osteoarthritis are lacking. Most available data come from animal studies or in vitro experiments, and the precise mechanisms by which PRPs may benefit cartilage health remain to be fully elucidated.

In summary, while there is some scientific rationale and preclinical evidence for the use of proline-rich peptides in supporting cartilage health, high-quality human clinical evidence is insufficient. Therefore, the evidence rating is 2 out of 5.