Collagen peptides (hydrolysed collagen)

Collagen peptides, also called hydrolysed collagen or collagen hydrolysate, are produced by enzymatic hydrolysis of animal collagen (typically bovine, porcine or fish skin and bone) to fragments of about 2-5 kDa. Iwai and colleagues (2005) demonstrated that hydroxyproline-containing dipeptides, notably Pro-Hyp and Hyp-Gly, appear in human plasma after oral ingestion, providing evidence for absorption beyond free amino acids. Randomised trials of 2.5-10 g per day for 8-24 weeks show modest improvements in skin hydration and elasticity, and meta-analyses report pain reduction in knee osteoarthritis. Effects on bone mineral density and tendon healing are less consistent. Collagen peptides are regulated as food in the EU and have no EU-authorised health claim.