Glucosamine
Herbal products and dietary supplements
Herbal products and dietary supplements
An amino sugar used by cartilage, sold for osteoarthritis. Evidence for knee pain is inconsistent; it may raise the INR with warfarin.
Also called: Glucosamine sulfate, Glucosamine hydrochloride
Quick facts
- Group
- Herbal products and dietary supplements
- Target
- Cartilage glycosaminoglycan synthesis (substrate)
- Used for
- Knee osteoarthritis · Hip osteoarthritis
- Key effects
- Mild diarrhoea · Nausea
- Monitor
- INR in patients on warfarin · Joint pain and function
- ATC
- M01AX05
No doses: the clinician sets them by the current guideline.
Mechanism of action
Glucosamine is a building block of glycosaminoglycans and proteoglycans, the molecules that give joint cartilage its structure. In osteoarthritis, cartilage breakdown outpaces its repair, and supplementation is thought to supply substrate for repair. Clinical results depend on the formulation (sulfate or hydrochloride) and are inconsistent; a large trial showed no slowing of joint-space narrowing.
- Glucosamine is absorbed after oral intake
- It is a substrate for cartilage glycosaminoglycans
- Proposed support of cartilage repair
- Inconsistent effect on knee pain
Indications
- Knee osteoarthritis: inconsistent evidence; guidelines disagree, several recommend against it Knee Osteoarthritis →
- Hip osteoarthritis: not supported by the evidence Hip Osteoarthritis →
Adverse effects
Common
- Mild diarrhoea, heartburn and cramps
- Nausea
Contraindications
- Use with warfarin without close INR monitoring
Key interactions
- Warfarin
- Raised INR with bruising and bleeding; seems related to the amount taken
- Antidiabetic drugs
- May raise blood glucose in some people
What is monitored
- INR in patients on warfarin
- Blood glucose in diabetes
- Joint pain and function
Pregnancy and breastfeeding
Little is known about its safety in pregnancy or breastfeeding.
Nursing care
- Ask every patient about herbal products and supplements and record them with the medicine list
- Check INR more closely when a patient on warfarin starts or changes glucosamine
- Teach that «natural» does not mean safe and that supplements are not approved as medicines before sale
Pharmacokinetics
- Absorption
- Taken by mouth as the sulfate or hydrochloride salt; commercial glucosamine is obtained from crustacean shells
Test yourself
Think of the answer, then tap the question to see it.
What is glucosamine's biological role?
It is a building block of glycosaminoglycans in joint cartilage.
Which interaction of glucosamine matters for anticoagulated patients?
It can raise the INR in patients on warfarin, increasing bleeding.
Is glucosamine supported for hip osteoarthritis?
No; the evidence does not support it.
Connections
← Back to the class: Herbal products and dietary supplements
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Glucosamine and Chondroitin for Osteoarthritis: What You Need To Know (National Center for Complementary and Integrative Health (NCCIH), 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.