Collagen Peptides

Collagen peptides are made by hydrolysing collagen, a process that uses enzymes, acid or alkali to cut the long, tightly wound collagen fibres into much shorter fragments ^[1]. This is a further step beyond the making of gelatin, which is only partially broken down; the additional hydrolysis produces peptides that dissolve readily even in cold water and have little taste or gelling ability, which makes them convenient to add to drinks and foods ^[1]. Like the collagen they come from, the peptides are unusually rich in the amino acids glycine, proline and hydroxyproline ^[1].

The raw material is collagen-rich animal tissue, most often the hides and bones of cattle, the skin of pigs, or the skin and bones of fish, the last of these giving so-called marine collagen ^[1]. Manufacturers extract and purify the collagen and then hydrolyse it under controlled conditions, with enzymatic methods generally favoured for their shorter processing time and cleaner products ^[1]. The result is a fine powder that is widely used in dietary supplements, in foods as a protein ingredient, in cosmetics, and in medical products such as wound dressings ^[1].

The most studied benefit of collagen peptides concerns the skin. In several double-blind, placebo-controlled trials, women who took specific collagen peptides daily for a couple of months showed measurable improvements in skin elasticity and moisture, and in one study a significant reduction in eye wrinkles alongside increased production of the skin's own collagen and elastin ^[2][3]. A systematic review and meta-analysis pooling many such trials concluded that oral collagen supplementation can improve skin hydration and elasticity compared with placebo, while noting variation between studies and calling for larger high-quality trials ^[4].

Collagen peptides are also widely promoted for joint and bone health, on the idea that supplying the building blocks of cartilage and bone might support these tissues ^[1]. The evidence here is weaker and less consistent; a European food-safety assessment concluded that a cause-and-effect relationship between eating collagen hydrolysate and the maintenance of joints had not been established ^[1]. Research continues, but the strongest human data so far relate to skin rather than to joints or bones ^[1][4].

When collagen peptides are eaten, they are digested into free amino acids and small peptides, some of which, such as the proline and hydroxyproline pair, can be absorbed intact and may act as signals that encourage skin and connective-tissue cells to make more collagen, a proposed explanation for the observed effects ^[1][2]. As a food-derived protein, hydrolyzed collagen is regulated as a food or dietary supplement rather than as a drug and is generally regarded as safe when properly processed; it is sold as plain powders, capsules, drinks and protein bars, and is often combined with vitamin C and other ingredients ^[1].

Very safe for most people, with occasional mild digestive upset or a feeling of fullness. Quality and heavy-metal testing vary by brand, so third-party tested products are worth it. Marine collagen can trigger fish allergies.