Undenatured CII has been proposed to improve joint pain through an effect on the immune system. More specifically, CII peptides are thought to induce the formation of regulatory T cells (Tregs) in areas of the gut known as Peyer’s patches. These Tregs can enter circulation, where they produce anti-inflammatory compounds (e.g., IL-10), which in theory can inhibit inflammation and tissue damage in joints.
The hydrolysis of type II collagen seems to result in the breakdown of the most immunologically active peptides, meaning that the effect of hydrolyzed collagen on joints may not act via this mechanism. However, in higher doses, hydrolyzed CII might improve joint pain by supplying the amino acids used to repair the damaged tissue.