Short answer. Probably not. When large trials were pooled, these supplements eased pain by less than the smallest amount people notice.

Evidence grade. Probably does not help.

What it is

Glucosamine and chondroitin are building blocks of cartilage. They are sold as tablets and powders over the counter, alone or together, and are often marketed for joint health. The idea is that taking them gives the body material to repair worn cartilage.

What the research shows

A network meta-analysis pooled 10 large trials with 3,803 people with knee or hip arthritis. On a 10 cm pain scale, glucosamine eased pain by 0.4 cm more than placebo, chondroitin by 0.3 cm and the two together by 0.5 cm. The authors had set the smallest difference worth having at 0.9 cm, and none of the results reached it. The supplements also made no difference to how fast the joint space narrowed on X-ray.¹

Trials paid for by manufacturers found bigger effects than independent trials. The authors concluded that health insurers should not cover these products.¹ Major guidelines, including the 2021 American Academy of Orthopaedic Surgeons guideline, do not recommend them.²

Risks and effort

They are safe for most people. Some products are made from shellfish, so check the label if you have a shellfish allergy. Glucosamine has been reported to raise the effect of warfarin, so tell your doctor if you take it. If you decide to try them, set a trial period of a few months and stop if you notice no change.

What usually works instead

Exercise and strength work for the leg muscles, weight loss where that applies, and simple pain relief have the best evidence. See Osteoarthritis of the Knee and Does exercise work for knee arthritis?.

Questions people ask

My mother swears by it. Is it all placebo?

Most knee arthritis pain rises and falls on its own, and any treatment you expect to work can feel better for a while. Large trials with a placebo group are the way to tell how much came from the supplement. On average, very little did.

Does one brand work better?

Products differ in the type and the dose. The trials pooled in the review above used quality checked products at standard doses, and the average effect was still too small to matter.

Is it better with chondroitin added?

The combination did slightly better on paper, but the difference from placebo was still below the level people notice.

Is it safe to take long term?

For most people, yes. Check the points under risks and effort first, and review it with your doctor once a year like any other regular medicine.

References

Wandel S, Jüni P, Tendal B, Nüesch E, Villiger PM, Welton NJ, Reichenbach S, Trelle S. Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis. BMJ. 2010;341:c4675. https://doi.org/10.1136/bmj.c4675
American Academy of Orthopaedic Surgeons. Management of osteoarthritis of the knee (non-arthroplasty): evidence-based clinical practice guideline. 3rd ed. Rosemont (IL): AAOS; 2021.

Last reviewed 22 October 2026. Next review due October 2028.