Collagen is a protein that provides structure to the skin, bones, tendons and other tissues. The body produces less collagen as people age, contributing to changes such as reduced skin elasticity and firmness.
That decline has helped drive interest in collagen injections, creams, foods and dietary supplements marketed for skin and other health benefits. But the evidence behind those products is not equally strong.
Collagen injections
Collagen has been used as an injectable dermal filler to improve the appearance of facial lines and restore lost volume. It has not simply been replaced by a single newer treatment, although other types of dermal fillers are now widely used.
The U.S. Food and Drug Administration says dermal fillers can improve the appearance of facial lines and age-related volume loss when used for approved purposes. Depending on the material, possible complications include swelling, pain, itching, infection, allergic reactions and, rarely, serious problems caused by accidental injection into a blood vessel.
Some fillers contain animal-derived materials, including bovine collagen, and the FDA advises that people may need allergy testing before receiving certain products.
What about collagen creams?
Collagen is a large protein, so simply applying collagen to the surface of the skin does not mean that the protein will penetrate deeply enough to replace the body’s own collagen.
That does not mean every skin cream containing collagen is necessarily useless. The effect of a cosmetic product depends on its formulation and other ingredients, and claims that a topical collagen product can rebuild the skin’s underlying collagen should be treated carefully.
Eating collagen
Hydrolyzed collagen supplements, often sold as powders, capsules or drinks, have been studied for their possible effects on skin.
Some clinical trials and earlier meta-analyses have reported improvements in measures such as skin hydration and elasticity. A 2023 systematic review and meta-analysis covering 26 randomized controlled trials and 1,721 participants found statistically significant improvements in those measures, although the researchers also identified limitations in the evidence and called for larger trials.
More recent evidence has been less conclusive.
A 2025 systematic review and meta-analysis of 23 randomized controlled trials involving 1,474 participants found that collagen supplements appeared to improve hydration, elasticity and wrinkles when all studies were considered together. But when researchers examined studies according to funding source and study quality, the apparent benefits were no longer significant in higher-quality or non-industry-funded studies. The authors concluded that there was not currently clinical evidence supporting collagen supplements for preventing or treating skin aging.
That means collagen supplements should not be presented as a proven way to reverse skin aging. The research remains an active area of study.
Collagen and overall nutrition
Eating enough protein is important because the body needs amino acids to build and maintain tissues, including collagen. But consuming collagen is not the same as sending collagen directly to the skin.
When collagen is eaten, the digestive system breaks it down into smaller components that the body can use. A balanced diet that provides adequate protein, vitamins and minerals remains important for normal tissue maintenance.
Claims that collagen supplements can build muscle, heal wounds or improve immune function require separate evidence and should not automatically be inferred from studies of skin hydration or elasticity.
Choosing collagen products
People considering a collagen supplement should also pay attention to the product’s source, labeling and quality.
Collagen used in supplements is commonly derived from animal sources such as cattle, pigs, chickens or fish. The fact that a product contains animal-derived collagen does not by itself mean it is contaminated, but dietary supplements can vary in quality.
The FDA says manufacturers are responsible for ensuring dietary supplements meet applicable requirements for identity, purity, strength and composition, including controls intended to limit contamination. The agency also notes that it does not approve dietary supplements for safety and effectiveness before they reach the market in the same way it approves drugs.
Consumers should therefore be cautious about products making broad claims about reversing aging, treating disease or producing dramatic changes in appearance.
Collagen is an important structural protein in the body, but the evidence does not support treating every collagen product as equivalent. For skin health, some studies have reported benefits from oral collagen supplements, while newer research has raised questions about the quality and reliability of those findings. More rigorous research is needed to establish who is most likely to benefit and how much of an effect the supplements have.
