Chondroitin is a high molecular weight polysaccharide, i.e. a long chain made up of sugar molecules. In particular, it consists of alternating sequences of D-glucuronate molecules and residues of N-acetyl-D-galactosamine-4/6-sulfate (two different sugars).

Inside the body's tissues, chondroitin sulphate is bound to calcium, an element to which it has great affinity, or is combined with proteins in complexes called mucoids.

Based on the chemical and physical characteristics, and the tendency to form protein complexes, different types of chondroitin sulfate are distinguished:

  • chondroitin-4-sulfate (chondroitin sulfate A)
  • dermatan sulfate (chondroitin sulfate B)
  • chondroitin-6-sulfate (chondroitin sulfate C)
  • chondroitin-2,6-sulfate (chondroitin sulfate D)
  • chondroitin-4,6-sulfate (chondroitin E)

Chondroitin sulfate A is found mainly in cartilage, varieties B and C are found in tendons, heart valves, aorta and skin, while varieties C, D and E are important in bone formation. Like glucosamine. , chondroitin sulfate is one of the essential components that make up the cartilage of the joints, giving it a high resistance to compression.

Its physiological function is to maintain the elasticity of the cartilage itself, prevent its degradation and mitigate inflammation by reducing the production and activation of inflammatory mediators in the cells that produce the components of the cartilage (chondrocytes). The chondroitin sulphate contained in the Commercial preparations are extracted from cow cartilage (typically from the trachea) or shark cartilage.

In Italy, chondroitin sulphate is indicated for the treatment of disorders (symptoms) caused by arthrosis (or osteoarthritis) of the knee and hip and is available as a medicinal product obtainable upon presentation of a repeatable medical prescription (class C). It is taken by mouth and the recommended daily dose is 800 - 1200 milligrams (mg), basically 2 or 3 tablets of 400 mg to be taken for periods of 3 months interspersed with periods of interruption.

To establish the most appropriate dosage and timing for the specific disease, the doctor or specialist should always be consulted.

Chondroitin sulfate, alone or in combination with glucosamine and / or other components such as methylsulfonylmethane (MSM), is also available as a dietary supplement, a form that does not require a prescription to purchase and generally has lower dosages than those present in preparations that require a medical prescription.

In the form of a supplement it is widely used to alleviate pain and joint stiffness in osteoarthritis. Its activity is complementary to that of glucosamine, so the two substances are often taken in combination. It should be considered that different supplements, of different brands, they may contain different amounts of these compounds, even far below the pharmacologically active dose, and this can greatly influence the effectiveness of the treatment. Chondroitin can also be found in the form of an ointment, although there is no evidence that it can be absorbed into the skin.

The European Food Safety Authority (EFSA) does not provide specific indications for products based on chondroitin and chondroitin sulphate, as there is insufficient scientific evidence to justify a cause-and-effect relationship between the intake of this compound and the maintenance of a normal cartilage.

However, its ability to relieve pain and improve joint function is recognized. Although the times it takes to have an effect are much longer than those of common pain relievers or anti-inflammatory drugs (a few months, based on individual response), the side effects are very low.

Chondroitin sulfate, in combination with hyaluronic acid and other natural compounds, such as curcumin and quercetin, is also used for the control of interstitial cystitis (urinary tract infection), as it helps restore the integrity of the tissue that makes up the urethra ( urothelium) and exerts an "anti-inflammatory and pain-relieving activity.

Undesirable (side) effects and contraindications

Although the efficacy of chondroitin sulfate in improving osteoarthritis remains uncertain, it still appears to be a relatively safe therapeutic option. stomach, nausea, diarrhea, erythema.

However, it should not be used in case of ascertained or presumed hypersensitivity to the active ingredient. Its interaction with other drugs is also known, in particular chondroitin sulphate could increase the effect of anticoagulants and antiplatelet agents.

It should also be noted that the concentration and purity of this substance, as well as the presence of any contaminants in commercially available supplements are not always reported.It is advisable in any case, before taking any supplement, to follow the advice of your doctor or specialist.


EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on the substantiation of health claims related to chondroitin and chondroitin sulphate and maintenance of joints (ID 1504, 1505) pursuant to Article 13 of Regulation (EC) No 1924/20061. EFSA Journal. 2009; 7:1262 

Zhu X, Sang L, Wu D, Rong J and Jiang L. Effectiveness and safety of glucosamine and chondroitin for the treatment of osteoarthritis: a meta-analysis of randomized controlled trials. Journal of Orthopedic Surgery and Research. 2018; 13:170

Simental-Mendía M, Sánchez-García A, Vilchez-Cavazos F, Acosta-Olivo CA, Peña-Martínez VM, Simental-Mendía LE. Effect of glucosamine and chondroitin sulfate in symptomatic knee osteoarthritis: a systematic review and meta-analysis of randomized placebo-controlled trials. [Synthesis] Rheumatology International . 2018; 38:1413

Volpi N. Quality of different chondroitin sulfate preparations in relation to their therapeutic activity. [Synthesis] Journal of Pharmacy and Pharmacology. 2009; 61:1271

In-depth link

National Institutes of Health (NIH). National Center for Complementary and Integrative Health (NCCIH). Glucosamine and chondroitin for osteoarthritis (English)

NHS. Osteoarthritis supplement study (English)

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