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What is glucosamine?

Glucosamine is an amino sugar made from chitin, which is extracted from the shellfish shells.

It also occurs in small amounts in certain foods and in the human body ─ in the cartilage and in the fluid that surrounds the joints.

Chemical Formula

Chemical formula of glucosamine is C6H13NO5 [4]. Glucosamine is a monosaccharide, so it is a carbohydrate [7].

Glucosamine structure image

Picture 1. Glucosamine chemical formula

What is glucosamine used for?

Glucosamine is used to treat joint pain, mainly knee pain due to osteoarthritis (cartilage damage in joints due to wear and tear) but also for hip and back pain, tendonitis, gout,  glaucoma, wound healing and hair growth. Long distance runners often use it.

Glucosamine Supplements


  • Glucosamine
  • Glucosamine sulfate
  • Glucosamine chondroitin sulfate
  • Glucosamine hydrochloride
  • N-acetyl-glucosamine
  • Glucoamine MSM (Methyl SulfonylMethane)

Forms. Glucosamine is available as tablets, capsules, chewables, powder, liquid for oral use and  as lotion for topical use (to apply on the skin).

In Europe, glucosamine is sold as a drug and in the United States as an over-the-counter (OTC) dietary supplement [2].

Does glucosamine work?

There is INSUFFICIENT EVIDENCE about effectiveness of glucosamine in relieving joint pain caused by osteoarthritis.

  • In one 2009 Cochrane review of high quality studies, glucosamine was no more effective than placebo [2].
  • In the GAIT study in the U.S. in 2002, glucosamine tablets (3 x 500 mg/day) in combination with chondroitin sulfate tablets (3 x 400 mg/day) reduced pain (after 6 months of taking) in some individuals with moderate to severe knee pain but not in those with mild pain [1]. After 24 months of taking, X-ray studies of the knees did not reveal any benefit for cartilage over placebo, though.

There is also insufficient evidence about glucosamine effectiveness in weight loss and treatment temporomandibular joint (TMJ) pain and glaucoma.

Usual Dosage

Tablets: 1500 mg in one dose or 3 x 500 mg/day [2]


Glucosamine is likely safe to use.

Glucosamine does not likely affect blood glucose levels in healthy individuals and those with diabetes mellitus [6].

During Pregnancy and Breastfeeding

Do not take glucosamine if you are pregnant or you are breastfeeding. The safety of glucosamine during pregnancy and breastfeeding is not known due to insufficient studies [3].

Side Effects

Side effects after glucosamine pills are rare and may include stomach upset, heartburn, nausea, diarrhea or constipation [3].

Individuals with a shellfish allergy are typically allergic to shellfish meat and not shells, from which glucosamine is extracted.

Glucosamine sulfate does not likely raise blood cholesterol levels [8].

Glucosamine-Drug Interactions

Glucosamine taken along with warfarin (a blood thinner) may increase the effectiveness of warfarin and thus increase the risk of bleeding but more research is warranted [5].

Frequently Asked Questions

1. Is glucosamine vegan?

Glucosamine is usually produced from the shellfish shells, but synthetically produced from wheat or corn, and therefore vegan, supplements are available.

2. What ingredients glucosamine supplements contain?

Besides glucosamine, supplements may contain shark cartilage and chondroitin.

  1. 2002, Glucosamine/Chondroitin Arthritis Intervention Trial Primary Study  National Center for Complementary and Alternative Medicine
  2. Towheed T et al, 2009, Glucosamine for osteoarthritis  Cochrane Summaries
  3. Glucosamine  Drugs.com
  4. Glucosamine  ChemSpider
  5. Knudsen JF, 2008, Potential glucosamine-warfarin interaction resulting in increased international normalized ratio: case report and review of the literature and MedWatch database  PubMed
  6. Simon RR et al, 2011, A comprehensive review of oral glucosamine use and effects on glucose metabolism in normal and diabetic individuals  PubMed Central
  7. Sugars and Polysaccharides  Southern Illinois University
  8. Does glucosamine raise “bad” LDL cholesterol?  ConsumerLab

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