Many products containing collagen, including creams and powders, claim to revitalize the skin. However, despite the marketing of these products as ways to increase the levels of collagen within the body, collagen molecules themselves are too big to be absorbed through the skin.
The benefits of these products, where they exist, are most likely attributable to their moisturising effects, but they do not strengthen the skin or directly increase collagen concentration in the skin. Such over-the-counter treatments are also not classified as drugs, meaning that there is no requirement for scientific validation of the claims made regarding their efficacy.