What is it?
The main structural protein of skin, bone and connective tissue. Collagen used in cosmetics is taken from animals such as cattle, chickens and fish. It is a very large molecule, so when applied to the skin it cannot pass through the skin barrier; instead it helps improve skin hydration at the surface. In products it works mainly as a skin and hair conditioner and moisturizer, and it is used in skin care and hair care.
Key information
- Collagen in cosmetics is an animal-derived protein that acts as a moisturizer and skin and hair conditioner.
- Applied to the skin, native collagen is too large to penetrate and cannot replace the skin's own collagen.
- The CIR Expert Panel concluded in 2017 that collagen is safe in the present practices of use and concentration.
- Labels do not say which animal the collagen came from, which matters for people with fish allergy.
More information
Collagen makes up 70 to 80 percent of the dry weight of the skin’s dermis and gives skin its strength. It is not one protein but a family, and cosmetic collagen can come from many land and marine animals, so its exact makeup varies with the source. Native collagen molecules are huge, from about 130,000 to more than 1,000,000 daltons. A 2025 review in Advances in Wound Care explains that topically applied native collagen cannot penetrate the skin barrier and that the idea that it replaces the skin’s own collagen is a common misconception; what it can do is improve skin hydration. For the broken-down form, see our Hydrolyzed Collagen profile.
The Cosmetic Ingredient Review (CIR) Expert Panel assessed collagen along with 18 related proteins and in its 2017 final report concluded that they are safe in the present practices of use and concentration. An industry survey reported collagen at up to 96 percent in face and neck products. Related collagen ingredients were not irritating in laboratory and human skin tests, though case reports describe allergic reactions to cosmetics containing fish-derived collagen.
The panel raised two practical points. Because fish protein is a food allergen and “collagen” on a label does not say it came from fish, it advised manufacturers to label fish-derived ingredients for people with fish allergy. And while collagen made only from hides and skins is not considered a disease risk, the panel stressed that collagen from other cattle materials must be free of infectious agents such as BSE (“mad cow disease”); U.S. rules bar prohibited cattle materials from cosmetics. Collagen is also an animal product, which matters if you avoid them.
Sources: Cosmetic Ingredient Review: Safety assessment of skin and connective tissue-derived proteins and peptides as used in cosmetics (final report, 2017); Advances in Wound Care (2025): Collagen-based products in wound, skin, and health care
