Glucosamine /
Chondroitin Sulfate

Glucosamine / Chondroitin Sulfate: Overview

Glucosamine is a key compound of the substance that makes up connective tissue such as cartilage.  Chondroitin sulfate should be equally effective, but is more expensive and recent product evaluations showed some did not contain the chondroitin claimed on the label.

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Glucosamine is a precursor to both Chondroitin Sulfate (the major glycosaminoglycan in cartilage) as well as hyaluronic acid (the major glycosaminoglycan in synovial fluid).

The cartilage of cows and even more obtainable from chickens is loaded with proteoglycans similar to Glucosamine and Chondroitin.  Most chondroitin appears to be made from extracts of cartilaginous cow and pig tissues (cow trachea and pig ear and nose), but other sources such as shark, fish and bird cartilage are also used.  Since chondroitin is not a uniform substance, and is naturally present in a wide variety of forms, the precise composition of each supplement will vary.

While both acid and base hydrolysis will prepare crude cartilage into Chondroitin Sulfate, enzymatic digestion of cartilage should produce a product that is both more absorbable and sulfated.  Chondroitin Sulfate can be found in a number of different formulations for osteoarthritis and other joint complaints.

Chondroitin Sulfate can be synthesized by humans, using glucuronic acid and N-acetylgalactosamine as building blocks.

Glucosamine can be purchased in salt form, or an acetylated form (N-Acetylglucosamine or NAG).  NAG is a normal intermediate between glucosamine and the molecules that make up cartilage and synovial fluid.  The most popular salt forms are the HCl and sulfate forms.  Neither salt form of glucosamine is "better" than the other, they both dissolve and absorb equally and are treated the same by the body.  The HCl form contains more glucosamine by weight, since HCl is lighter than H2SO4.  Both salt forms seem to exceed NAG as a therapeutic agent.  Glucosamine is often supplied alone or is commonly mixed with other joint supporting ingredients such as chondroitin sulfate and bioflavonoids.

Function; Why it is Recommended

Chondroitin Sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars (N-acetylgalactosamine and glucuronic acid).  A chondroitin chain can have over 100 individual sugars, each of which can be sulfated in variable positions and quantities.  Understanding the functions of such diversity in chondroitin sulfate and related glycosaminoglycans is a major goal of glycobiology.

Sometimes called a mucopolysacharide, Chondroitin Sulfate is added to various proteins to make up proteoglycans, which are water-retaining molecules that are the building blocks of cartilage.  In general, it is one the major building blocks of cartilage, bone and aorta tissues.

Glucosamine promotes the production of proteoglycans; Chondroitin Sulfate is the nutrient that blocks the enzymes that destroy cartilage.

Chondroitin sulfate is an important structural component of cartilage and provides much of its resistance to compression.  Chondroitin sulfate is a major component of extracellular matrix, and is important in maintaining the structural integrity of the tissue.

Chondroitin sulfate readily interacts with proteins in the extracellular matrix due to its negative charges.  These interactions are important for regulating a diverse array of cellular activities.  In the nervous system, chondroitin sulfate proteoglycans regulate the growth and development of the nervous system as well as the nervous system's response to injury.

This nutrient is a constituent of the arterial wall and has anti-coagulant (prevents blood stickiness), anti-lipemic (anti-fat in blood stream) and anti-thrombogenic (prevents clots) properties.

NAG is also the precursor to mucin, one of the components lining the gut wall and other mucous membranes.  This makes NAG an excellent ingredient for the support of the gut wall lining.

Glucosamine supplementation has established a very good track record of clinical trials in combating the symptoms associated with osteoarthritis.  When compared with ibuprofen, 1500mg/day of glucosamine was equal in reducing pain after 8 weeks.  The great benefit to glucosamine supplementation is that it is a precursor to cartilage formation, while ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDS) actually prevent the repair of joint tissue while covering only the pain.

Taken early before arthritis begins, it may ward off this disease.

Chondroitin Sulfate has been supplied as a supplement to help in cases of osteoarthritis.  Recent research has confirmed the use of oral Chondroitin Sulfate (1200mg/day) for knee, hip, and finger osteoarthritis.

The use of NAG for osteoarthritis is only diminished by it's inability to be absorbed as well as pure glucosamine.


Typical doses of either are 500mg tid and sometimes lower doses for maintenance purposes.  The dosage of oral chondroitin used in human clinical trials is 800-1,200mg per day.

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Glucosamine / Chondroitin Sulfate:

Glucosamine / Chondroitin Sulfate can help with the following:


Not recommended for



Clinical studies comparing glucosamine (in sulfate or hydro-chloride form) with both placebo and standard arthritis drugs (including Ibuprofen) have shown that glucosamine outperformed both in reducing long-term pain, joint tenderness and swelling, accelerating recovery, reversing cartilage damage, and helping to restore joint function, range of motion, and walking speed.  Glucosamine is a component of hyaluronic acid which has been used by injection to successfully reduce knee pain.

Three years of treatment with glucosamine sulfate (1500mg per day) prevented joint space narrowing and reduced pain in two randomized, double-blind, placebo-controlled trials with a total of 414 women, including 319 of postmenopausal age.
[North American Menopause Society 12th Annual Meeting, Oct. 4-6, 2001, New Orleans, LA.]

Along with glucosamine, chondroitin sulfate has become a widely used dietary supplement for treatment of osteoarthritis.  Due to the popularity of the glucosamine-chondroitin supplement and the lack of reliable information about its usefulness in treating osteoarthritis [McAlindon TE et al (2000); Glucosamine and Chondroitin for Treatment of Osteoarthritis: A Systematic Quality Assessment and Meta-analysis; JAMA 283: pp.1469-1475.] the National Institutes of Health funded a study to test the effects of chondroitin and glucosamine on osteoarthritis of the knee.

This multicenter, placebo-controlled, double-blind, six month long trial found that glucosamine plus chondroitin had no statistically significant effect on symptoms of osteoarthritis.[Clegg DO et al (2006); Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis; New Engl J Med 354 (8): pp.795-808.]

The control group of patients who took celecoxib (a commonly used osteoarthritis drug) did have a statistically significant improvement in their symptoms.  These results indicate that glucosamine and chondroitin do not effectively relieve osteoarthritic pain.  Although the study found no overall effect for the supplements, a secondary analysis of a subgroup of patients suggested that the supplements taken together helped people with more severe pain.

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