Protein crosslinks

Protein crosslinks are covalent bonds that join two protein molecules, or two parts of the same protein. They can form on purpose, by enzymes (as in collagen maturing). Or they can form by accident, through oxidation and 'glycation' by sugars and reactive aldehydes. The harmful ones build up in your long-lived structural proteins, like collagen, elastin, and the crystallins in your eye lens, stiffening tissues. That contributes to stiff arteries, aging skin, cataracts, and less elastic organs.

Last reviewed: June 22, 2026

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