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Collagen is most commonly found in the skin, bones and connective tissue within the body, providing structural support, strength and a degree of elasticity (in combination with elastin). In particular, collagens can be found in the extracellular matrix - an intricate network of macromolecules that determine the physical properties of body tissues.
Collagen is secreted by a variety of different cells, but primarily by connective tissue cells. Collagen production naturally declines with age, reducing the structural integrity of the skin and leading to sagging skin, the formation of lines and wrinkles and the weakening of cartilage in joints. While young, the body consistently produces collagen, but collagen synthesis begins to decline around over the age of 25 , with a dramatic reduction in synthesis in women after menopause. By the age of 60 there is typically a considerable decline in collagen production.
collagen helps form a fibrous network, upon which new cells can grow. Collagen is also required in the replacement and restoration of dead skin cells. Some collagens also function as protective coverings for delicate organs in the body such as the kidneys.