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Glucosamine and Chondroitin: Forms, Evidence and Safety

Also known as glucosamine sulfate, glucosamine hydrochloride, glucosamine HCl, chondroitin sulfate, glucosamine chondroitin, joint supplement

Short answer

Glucosamine and chondroitin are natural parts of joint cartilage, sold in the US as dietary supplements, alone or together [1]. Labels show glucosamine sulfate or hydrochloride and chondroitin sulfate [1]. Research for knee osteoarthritis is inconsistent, and guidelines disagree [1]. Glucosamine may raise blood sugar in some people, and both are linked to bleeding with warfarin [1].

Last reviewed · 2 sources

What is Glucosamine and Chondroitin?

Glucosamine and chondroitin are constituents of cartilage, the cushioning tissue in joints [1]. Glucosamine is a building block for glycosaminoglycans, molecules that are part of cartilage's structure, and chondroitin helps cartilage resist compression [1]. They are studied mainly for osteoarthritis, with inconsistent results [1].

Forms of Glucosamine and Chondroitin you'll see on labels

  • Glucosamine sulfate

    One of two glucosamine forms sold as supplements in the US [1]. Some countries sell a prescription crystalline glucosamine sulfate; a European expert group recommends that product but not other glucosamine formulations [1].

  • Glucosamine hydrochloride

    The other common US form; the large 2-year US trial used it [1].

  • Chondroitin sulfate

    Sold alone or combined with glucosamine [1]. Results differed by brand in some analyses, with a pharmaceutical-grade product doing better [1].

How Glucosamine and Chondroitin appears on a label

Glucosamine and chondroitin have no FDA Daily Value, so the Supplement Facts panel lists them by weight (mg) with "Daily Value not established" [2]. The weight shown must be the weight of the ingredient itself, such as glucosamine sulfate, not of a component of it [2]. In a proprietary blend, only the blend's total weight must be shown [2].

When to take Glucosamine and Chondroitin

No source we checked names a best time of day or says whether to take glucosamine or chondroitin with food.

What to keep apart from Glucosamine and Chondroitin

  • Warfarin

    Glucosamine and chondroitin have been associated with an increased risk of bleeding in people taking this anticoagulant [1]. Ask your pharmacist.

  • Diabetes medicines

    Glucosamine may raise blood glucose in some people [1]. Ask your doctor or pharmacist.

Who should ask a doctor or pharmacist first

Talk to a doctor or pharmacist first if you take warfarin, have diabetes or watch your blood sugar, or are pregnant or breastfeeding, since little is known about safety in pregnancy and breastfeeding [1].

Keep Glucosamine and Chondroitin in a routine that fits

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Glucosamine and Chondroitin: questions people ask

It is still uncertain. Studies have had inconsistent results, and expert reviews reach conflicting conclusions [1].

The 2019 American College of Rheumatology/Arthritis Foundation guideline strongly recommends against glucosamine and chondroitin for knee osteoarthritis [1]. The 2021 American Academy of Orthopaedic Surgeons guideline lists them as possibly helpful for mild-to-moderate knee osteoarthritis but calls the evidence inconsistent [1].

Both forms are sold as supplements in the US [1]. Trials have used both, and results have been mixed for each [1].

No major safety problems were found in large studies [1]. But glucosamine may raise blood sugar in some people, and both supplements are linked to bleeding risk with warfarin [1].

Ask your doctor first. Glucosamine may cause increases in blood glucose in some people [1].

Whether they affect joint structure is uncertain; two large 2-year trials gave conflicting results on joint space [1].

Little is known about the safety of glucosamine and chondroitin during pregnancy or breastfeeding [1]. Ask your doctor.

Evidence is limited. A guideline concluded moderate evidence does not support glucosamine sulfate for hip osteoarthritis, while one trial and one guideline point toward chondroitin for hand osteoarthritis [1].

Sources

  1. Glucosamine and Chondroitin for Osteoarthritis: What You Need To Know — NIH National Center for Complementary and Integrative Health (NCCIH)
  2. 21 CFR 101.36 – Nutrition labeling of dietary supplements — U.S. Food and Drug Administration (Electronic Code of Federal Regulations)

Educational information, not medical advice. The amounts above are official reference values, not a recommendation for you. Check with your doctor or pharmacist before starting or changing supplements, especially if you take medication, are pregnant or have a health condition. Supin sells a subscription, not supplements. Last reviewed .

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