Hydroxyproline Unit Converter

Hydroxyproline is a nonessential amino acid formed when proline is modified (hydroxylated) during collagen production. It is one of the most abundant amino acids in collagen, making up roughly 13–14% of its total amino acid content.

Because hydroxyproline is found almost exclusively in collagen, measuring it in blood or urine provides a window into how much collagen your body is breaking down or turning over. This makes it a useful indicator of bone and connective tissue metabolism.

The conversion of proline to hydroxyproline requires vitamin C, iron, molecular oxygen, and alpha-ketoglutarate. Without adequate vitamin C, this conversion fails and collagen cannot form its stable triple-helix structure.

Hydroxyproline is produced in the liver by hydroxylation of the amino acid proline. It is incorporated into collagen found in bone, cartilage, tendons, skin, and blood vessels, and is released into the bloodstream when collagen is broken down.