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Collagen Supplements: What They Are, Types, Sources and Evidence

VITAMINS & SUPPLEMENTS · COMPARED

Collagen vs Glucosamine for Joints: What Trials Compare

What trials and reviews say about oral collagen and glucosamine for knee osteoarthritis, which product types were tested, and why results cannot be transferred between them.

Content last updated . This page has not been medically reviewed.

Back to Collagen Supplements: What They Are, Types, Sources and Evidence
Quick answer
Collagen supplements and glucosamine have each been tested for knee osteoarthritis (OA), mostly against placebo. Direct comparisons are few: two trials compared undenatured type II collagen (UC-II) with a glucosamine and chondroitin combination, and both reported results favoring UC-II. NCCIH describes glucosamine results as inconsistent. [1] This page sets out what each source found; it does not say which a person should use.

How the evidence is labeled

Placebo-controlled means compared with an inactive look-alike. WOMAC and VAS are questionnaires and scales for pain, stiffness and function. A meta-analysis pools trials. These are symptom scores, not images of the joint. Proper evidence not found means we searched and found nothing usable.

What each one is

  • Glucosamine is a constituent of cartilage sold as glucosamine sulfate or hydrochloride, often with chondroitin; NCCIH notes some other countries sell certain preparations as prescription drugs. [1]
  • Collagen products differ: hydrolyzed collagen peptides and UC-II are separate interventions. UC-II is derived from chicken sternum cartilage. [2] See UC-II vs hydrolyzed collagen.

What the evidence found

5 findings · 5 limited or unclearThe colour follows the evidence label on each card.

  1. Glucosamine or chondroitin vs placebo in knee OA

    Government summary of many trials

    NCCIH says it is still uncertain whether they help knee OA symptoms; results were inconsistent. [1]

  2. Glucosamine sulfate, chondroitin sulfate and the two combined

    Meta-analysis; few combination trials

    A 2024 meta-analysis of 25 trials, all against placebo, found chondroitin reduced pain, glucosamine sulfate reduced joint space narrowing, and the combination did not reduce pain. [3]

  3. Oral collagen (mixed products) vs placebo

    Meta-analysis; high heterogeneity

    A 2025 meta-analysis of 11 trials (870 people) reported better function and pain scores, with high variation between trials. [4]

  4. UC-II vs glucosamine plus chondroitin

    Randomized trials; study amounts; funding not established in what we read

    In a 191-person trial, UC-II 40 mg, glucosamine 1500 mg plus chondroitin 1200 mg, or placebo for 180 days: UC-II improved total WOMAC more than placebo and than the combination. [2] An earlier 90-day trial reported a 33% WOMAC reduction with UC-II versus 14% with the combination. [5]

  5. Many supplements vs placebo

    Systematic review

    A 2018 review of 69 studies found glucosamine and chondroitin were ineffective or had small, arguably unimportant effects, and rated much of the evidence very low quality. [6]

The UC-II comparisons used one product type, one amount and one comparison combination. They do not show that other collagen products, or glucosamine alone, would behave the same way. The 2018 review also found that only green-lipped mussel extract and UC-II had clinically important pain effects at medium term. [6]

No universal winner

Each product type has trials with different amounts, durations and comparators, and no head-to-head result covers every product. Decisions belong with a clinician or pharmacist.

Frequently asked questions

Is collagen better than glucosamine for joints?

Proper evidence not found for a general answer. Two trials favored UC-II over glucosamine plus chondroitin, but they tested one collagen type. [2] [5]

Does glucosamine work?

NCCIH says it is uncertain whether glucosamine and chondroitin help knee OA symptoms. [1]

Are the collagen joint trials independent?

We could not confirm funding for every trial from the abstracts. A 2025 trial noted earlier collagen studies were mostly industry-sponsored. [8]

Can I take them together?

Proper evidence not found for collagen plus glucosamine against placebo in the sources we read. Ask a clinician or pharmacist, especially about warfarin. [1]

Does either rebuild cartilage?

Proper evidence not found for oral collagen rebuilding cartilage in the sources we read. For glucosamine, NCCIH says effects on joint structure are uncertain. [1]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Limits and uncertainty
Most UC-II trials last 3 to 6 months. [7] A 2025 randomized trial of UC-II plus hydrolyzed collagen in 68 people over 12 weeks found no difference from placebo. [8] Results at 3 to 6 months say little about years. Guidelines also differ on glucosamine, as NCCIH reports. [1]
Safety and who should ask first
  • NCCIH reports that glucosamine may raise blood glucose in some people and that glucosamine and chondroitin have been linked to bleeding risk in people taking warfarin. [1] Tell your pharmacist about any anticoagulant and see medication interactions.
  • Little is known about glucosamine and chondroitin in pregnancy or breastfeeding. [1] For collagen see collagen in pregnancy, breastfeeding and children.
  • Collagen from fish, egg or beef can trigger allergy; see collagen allergy. For signs of a severe allergic reaction, such as trouble breathing or swelling of the face or throat, call 911.
  • Persistent joint pain, swelling, redness or heat deserves a clinician's assessment. In England the NHS says GPs no longer prescribe glucosamine and chondroitin because there is no strong evidence they work. [9]

For a wider look at joint formulas see glucosamine, chondroitin and sports formulas.

References
  1. National Center for Complementary and Integrative Health (NCCIH, US). Glucosamine and Chondroitin for Osteoarthritis: What You Need To Know. Read 2026-10-23.
  2. Lugo JP, Saiyed ZM, Lane NE. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study. Nutr J 2016 (abstract read). Read 2026-10-23.
  3. Rabade A, Viswanatha GL, Nandakumar K, Kishore A. Evaluation of efficacy and safety of glucosamine sulfate, chondroitin sulfate, and their combination regimen in the management of knee osteoarthritis: a systematic review and meta-analysis. Inflammopharmacology 2024 (abstract read). Read 2026-10-23.
  4. Simental-Mendía M, Ortega-Mata D, Acosta-Olivo CA, et al. Effect of collagen supplementation on knee osteoarthritis: an updated systematic review and meta-analysis of randomised controlled trials. Clin Exp Rheumatol 2025 (abstract read). Read 2026-10-23.
  5. Crowley DC, Lau FC, Sharma P, et al. Safety and efficacy of undenatured type II collagen in the treatment of osteoarthritis of the knee: a clinical trial. Int J Med Sci 2009 (abstract read). Read 2026-10-23.
  6. Liu X, Machado GC, Eyles JP, Ravi V, Hunter DJ. Dietary supplements for treating osteoarthritis: a systematic review and meta-analysis. Br J Sports Med 2018 (abstract read). Read 2026-10-23.
  7. Kumar P, Bansal P, Rajnish RK, et al. Efficacy of undenatured collagen in knee osteoarthritis: review of the literature with limited meta-analysis. Am J Transl Res 2023 (abstract read). Read 2026-10-23.
  8. Yuenyongviwat V, Anusitviwat C, Tuntarattanapong P, et al. Efficacy of combined undenatured type II collagen and hydrolysed collagen supplementation in knee osteoarthritis: a randomised controlled trial. Sci Rep 2025 (abstract read). Read 2026-10-23.
  9. NHS (England). Osteoarthritis: treatment. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.