Eggshell membrane is a dietary supplement shown to be effective in reducing or treating osteoarthritis or other stiffness and joint pain. Eggshell membrane is the clear film lining the shell, visible when one peels a boiled egg. Eggshell membrane is primarily composed of fibrous proteins such as collagen type I, V and X. Other components identified in eggshell membranes are hyaluronic acid, sialic acid, desmosine and isodesmosine, ovotransferrin, lysyl oxidase, lysozyme, and β-N-acetylglucosaminidase.