CollagenCan collagen cause kidney stones?
Updated 9 Nov 2026
Short answer
It is not known. Collagen contains hydroxyproline, which the body can turn into oxalate, a part of calcium oxalate stones.[1] In one study, 30 g of gelatin raised oxalate in urine by 43% compared with 30 g of whey protein; doses of 1 and 2 g did not change it.[1] In another, 5 men took 30 g a day for 3 days, and oxalate in urine did not change.[2] Neither study counted kidney stones.[1][2]
Sources (2)
- Hydroxyproline ingestion and urinary oxalate and glycolate excretion. Knight J, Jiang J, Assimos DG, Holmes RP Kidney Int, 2006. PMID 17021603
- Theoretical and laboratory investigations of the effects of hydroxyproline ingestion on the metabolic and physicochemical risk factors for calcium oxalate kidney stone formation in a small group of healthy subjects. Rodgers A, Cele P, Ravenscroft N, Edmonds-Smith C, Jackson G Int Urol Nephrol, 2019. PMID 31161522
More about collagen
What is collagen?Can you get collagen from food?What is collagen used for?How long does collagen take to work?Is collagen safe?Does collagen help joint pain?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.