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Glucosamine chondroitin: does it work for joint pain?

By the Life in Good Form editors. Updated 2026-10-15.

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What glucosamine and chondroitin are

NCCIH explains that glucosamine and chondroitin are natural parts of cartilage, the cushioning tissue in joints. Glucosamine is a building block for molecules called glycosaminoglycans that make up cartilage structure, and chondroitin helps cartilage resist compression.

In the United States, they are sold as dietary supplements, separately or together, as glucosamine sulfate or glucosamine hydrochloride and chondroitin sulfate. In some other countries, certain preparations are prescription drugs. In a 2017 U.S. survey, chondroitin (with or without glucosamine) was the supplement most commonly used by people age 35 and older diagnosed with osteoarthritis.

What the research shows, joint by joint

Knee. There has been a substantial amount of research, but results have been inconsistent and expert reviews reach conflicting conclusions. Whether these supplements change joint structure, measured as joint space, is also uncertain.

Hip. The American Academy of Orthopaedic Surgeons concluded in 2017 that moderate strength evidence does not support glucosamine sulfate for hip osteoarthritis. The main study gave 222 people glucosamine sulfate or placebo for 2 years, and glucosamine was no better for pain, function or joint space narrowing.

Hand. In a 6-month trial of 162 people, chondroitin improved hand pain and function more than placebo. The 2019 American College of Rheumatology and Arthritis Foundation guideline conditionally recommends chondroitin for hand osteoarthritis.

Jaw. A review of 8 studies with 538 participants could not reach definite conclusions for temporomandibular joint osteoarthritis, but found use for 3 months or more linked to less pain and better mouth opening.

Safety

• Large studies. NCCIH says no major safety problems have been identified in large studies for osteoarthritis.
• Blood sugar. Glucosamine may raise blood glucose in some people. If you have diabetes, check your levels and talk with your doctor.
• Warfarin. Glucosamine and chondroitin have been associated with increased bleeding risk in people taking warfarin.
• Shellfish allergy. NOW Foods' Glucosamine & Chondroitin Extra Strength contains shellfish (crab, shrimp, lobster, crayfish), and the label says people with a known shellfish allergy should not use it.
• Pregnancy and breastfeeding. Little is known about safety during pregnancy or breastfeeding.
• Large tablets. NOW Foods directs taking its tablets with 8 oz of water because of their size.

Reading a glucosamine chondroitin label

• Form of glucosamine. Labels list glucosamine sulfate or glucosamine hydrochloride. NOW Foods' Extra Strength uses glucosamine sulfate from a potassium sulfate complex.
• Amounts. NOW Foods' serving is 2 tablets daily, giving 1,500 mg glucosamine sulfate and 1,200 mg chondroitin sulfate.
• Source. Chondroitin in that product comes from bovine cartilage, and the product contains shellfish. Check every label's allergen statement.
• Sodium. The same serving contains 110 mg of sodium, worth noting if you limit salt.
• Added ingredients. Many products add MSM, turmeric, collagen or hyaluronic acid. These change the formula and were not part of most glucosamine and chondroitin trials.

Is it worth trying?

Because the evidence is mixed, glucosamine chondroitin is not a sure bet for knee or hip pain. It has a reasonable safety record in large studies, so some people with knee or hand osteoarthritis try it after talking with their doctor. Chondroitin has the most support for the hand.

Osteoarthritis symptoms include pain, stiffness, swelling and trouble moving the joint, most often in the knees, hips and hands. A doctor can confirm the diagnosis and discuss proven treatments. A supplement should not replace that care.

What to look for when you buy

Questions people ask

Does glucosamine chondroitin work?

It is uncertain. NCCIH says knee studies have been inconsistent, evidence does not support glucosamine for hip osteoarthritis, and chondroitin has some support for the hand.

Is glucosamine chondroitin safe?

Large studies found no major safety problems, but glucosamine may raise blood sugar and both may increase bleeding with warfarin. Many products contain shellfish.

How long does glucosamine take to work?

Trials ran for months. The hand trial lasted 6 months, and the jaw review linked 3 months or more to less pain.

Can I take glucosamine if I am allergic to shellfish?

Check the label. NOW Foods' product contains shellfish and says people with a shellfish allergy should not use it.

Can diabetics take glucosamine chondroitin?

Talk with your doctor first. Glucosamine may raise blood sugar in some people.

Sources

• Glucosamine and Chondroitin for Osteoarthritis: What You Need To Know (nccih.nih.gov), National Center for Complementary and Integrative Health
• Glucosamine & Chondroitin Extra Strength Tablets (www.nowfoods.com/products/supplements/glucosamine-chondroitin-extra-strength-tablets), NOW Foods

Sources checked 2026-10-15.