Hydroxyproline

Hydroxyproline is an amino acid and a major component of collagen. The formation of hydroxyproline is catalyzed via the enzyme procollagen-proline dioxygenase via a reaction that requires vitamin C.

Elevated plasma hydroxyproline is associated with increased risk of connective tissue injuries and metabolic bone diseases. Elevated levels of hydroxyproline, a marker of collagen breakdown, was found by Wenzhong Xiao in the Severely Ill Patient Study. Robert Naviaux’s work has suggested it as a possible biomarker for female ME/CFS patients.