Collagen

Is collagen safe?

Updated 9 Nov 2026

Short answer

In osteoarthritis trials, collagen caused no more side effects than control, and in skin trials it was generally well tolerated.[1][2] People with a fish allergy may react to fish collagen.[3] Large doses of gelatin raised the oxalate in urine, a concern for people who have had kidney stones.[4] Skin trials enrolled adults aged 20 to 70, and no trial in pregnancy was found in PubMed.[5] Ask a doctor or pharmacist first if one of these applies to you.

Sources (5)

  1. Efficacy and safety of collagen derivatives for osteoarthritis: A trial sequential meta-analysis. Liang CW, Cheng HY, Lee YH, Liao CD, Huang SW Osteoarthritis Cartilage, 2024. PMID 38218227
  2. Efficacy and safety of hydrolyzed collagen supplementation on skin health outcomes: a systematic literature review of randomized controlled trials. Bassila C, Bassila JC, Slim M Eur J Clin Nutr, 2026. PMID 42342959
  3. Collagen-An Important Fish Allergen for Improved Diagnosis. Kalic T, Kamath SD, Ruethers T, Taki AC, Nugraha R, Le TTK, et al. J Allergy Clin Immunol Pract, 2020. PMID 32389794
  4. Hydroxyproline ingestion and urinary oxalate and glycolate excretion. Knight J, Jiang J, Assimos DG, Holmes RP Kidney Int, 2006. PMID 17021603
  5. Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis. de Miranda RB, Weimer P, Rossi RC Int J Dermatol, 2021. PMID 33742704

More about collagen

What is collagen?Can you get collagen from food?What is collagen used for?How long does collagen take to work?Does collagen help joint pain?Does collagen help your skin?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.