Anthocyanidins are a family of compounds found in dark-skinned fruits, berries and pine bark, which may help reinforce and preserve collagen in the body. Collagen is the most abundant protein in the body and forms connective fibres in tissues such as skin, ligaments, cartilage, muscles, and capillaries. When collagen is damaged, tissues can lose strength and elasticity. Research indicates that anthocyanidins play an active role in protecting the body's collagen. Vitamin C is also included as it supports normal collagen formation and the functioning of blood vessels, cartilage and skin.