Collagen is the most abundant protein in the body and helps structure our hair, skin, nails, bones and muscles. It keeps the skin firm, smooth and elastic. As the years go by and the body ages, collagen production gradually decreases. Collagen production decreases by 1% per year after the age of 25, but our need increases over time. This reduction in production levels causes, among other things, the loss of elasticity and flexibility of the skin, joints and muscles, etc. https://www.hollandandbarrett.com/the-health-hub/vitamins-and-supplements/supplements/skin-benefits-of-collagen/