Topic Overview

What are glucosamine and chondroitin?

Glucosamine and chondroitin are part of normal
cartilage. Cartilage acts as a cushion between the
bones in a joint.

Glucosamine, also called chitosamine, is a
natural substance that is found in the covering of shellfish. It is available
in different forms, including glucosamine hydrochloride, N-acetyl-glucosamine
(NAG), and glucosamine sulfate, which is a combination of glucosamine and
mineral salt. Glucosamine is also available in synthetic forms. The body
absorbs glucosamine well.

Chondroitin can come from natural
sources, such as shark or bovine cartilage, or it can be made in a lab.
Chondroitin is also known as chondroitin sulfate, chondroitin sulfuric acid,
and chonsurid. Chondroitin sulfate is a combination of chondroitin and mineral

Glucosamine and chondroitin are available in tablet,
capsule, powder, or liquid form and are often taken in combination with each
other or in combination with other dietary supplements. Glucosamine may be
taken separately as a dietary supplement for joints.

What are glucosamine and chondroitin used for?

Many people take glucosamine and chondroitin, alone or together, for
osteoarthritis. Some people believe this helps. But an analysis of studies looking at glucosamine or chondroitin for osteoarthritis in the hip or knee did not
show that these supplements slow joint destruction or relieve pain.footnote 1

Are glucosamine and chondroitin safe?

It appears that glucosamine and chondroitin, alone or
together, are safe and have few side effects. But they cost money and will not
help you more than a placebo. Talk to your doctor if you are thinking about taking glucosamine and

If you are allergic to shellfish, do not take
glucosamine unless you have talked to your doctor. Some glucosamine is
made from shellfish covering.

The U.S. Food and Drug
Administration (FDA) does not regulate dietary supplements in the same way it
regulates medicines. A dietary supplement can be sold with limited or no
research on how well it works.

Always tell your doctor if you are
using a dietary supplement or if you are thinking about combining a dietary
supplement with your conventional medical treatment. It may not be safe to
forgo your conventional medical treatment and rely only on a dietary
supplement. This is especially important for women who are pregnant or

When using dietary supplements, keep in mind the following:

  • Like conventional medicines, dietary
    supplements may cause side effects, trigger allergic reactions, or interact
    with prescription and nonprescription medicines or other supplements you might
    be taking. A side effect or interaction with another medicine or supplement may
    make other health conditions worse.
  • The way dietary supplements
    are manufactured may not be standardized. Because of this, how well they work
    or any side effects they cause may differ among brands or even within different
    lots of the same brand. The form of supplement that you buy in health food or
    grocery stores may not be the same as the form used in research.
  • Other than for vitamins and minerals, the long-term effects of
    most dietary supplements are not known.



  1. Wandel S, et al. (2010). Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of the hip or knee: Network meta-analysis. BMJ. Published online September 16, 2010 (doi:10.1136/bmj.c4675).

Other Works Consulted

  • Chondroitin (2015). Facts and Comparisons eAnswers. Accessed April 28, 2016.
  • Clegg DO, et al. (2006). Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. New England Journal of Medicine, 354(8): 795-808.
  • Drugs for osteoarthritis (2014). Medical Letter on Drugs and Therapeutics, 56(1540): 80-84. Accessed April 28, 2016.
  • Gabay C, et al. (2011). Symptomatic effects of chondroitin 4 and chondroitin 6 sulfate on hand osteoarthritis. Arthritis and Rheumatism, 63(11): 3383-3391.
  • Glucosamine (2016). Facts and Comparisons eAnswers. Accessed April 28, 2016.
  • Scott D (2009). Osteoarthritis of the hip, search date May 2007. Online version of BMJ Clinical Evidence:
  • Scott D, Kowalczyk A (2007). Osteoarthritis of the knee, search date October 2006. Online version of BMJ Clinical Evidence:


ByHealthwise Staff
Primary Medical Reviewer Anne C. Poinier, MD – Internal Medicine
Martin J. Gabica, MD – Family Medicine
Kathleen Romito, MD – Family Medicine
Specialist Medical Reviewer Stanford M. Shoor, MD – Rheumatology

Current as ofOctober 10, 2017