It makes up about 25-35% of the total protein in the body and is found in various tissues, including:

* Skin: Provides structure and elasticity

* Bones: Adds strength and flexibility

* Cartilage: Provides cushioning and support

* Tendons and ligaments: Connects muscles to bones and bones to bones

* Blood vessels: Provides strength and elasticity

* Eyes: Forms the cornea

Collagen is a fibrous protein that forms long, strong fibers. Its primary function is to provide structural support and strength to tissues.