Collagen supplements and skincare products dominate social media with promises of younger-looking skin, healthier joints, and improved gut health. Some cost £40 or more per month. But the evidence for these claims is weaker than marketing suggests.
Joan Chang, a collagen researcher and senior lecturer at the University of Manchester, explains the core problem. Collagen is the body's most abundant protein and exists in at least 28 different types with different structures and functions. When eaten, the digestive system breaks collagen down into smaller components that the body can use in various ways. This means consuming collagen does not deliver it intact to your face or knees.
Clinical trials show mixed results. A 2025 review of 23 trials found that apparent improvements in skin hydration or elasticity disappeared when researchers examined only higher-quality studies or those without pharmaceutical-industry funding. The evidence is contested.
Collagen applied directly to skin faces another barrier. Large collagen molecules generally cannot pass through intact skin, leaving many collagen creams functioning mainly as moisturisers.
The article also addresses PDRN, a substance often derived from salmon or trout DNA marketed as a way to boost collagen. Dan Baumgardt, a practising GP and lecturer at the University of Bristol, notes an important distinction between using a substance in wound healing and expecting a serum to rejuvenate healthy skin.
Microneedling, which uses tiny needles to puncture skin and stimulate repair, may improve scarring in professional settings but carries risks of infection and further scarring when attempted at home.
Outside beauty applications, collagen shows promise in medicine. Researchers have used its structural properties to develop wound dressings and experimental corneal implants designed to restore sight.