Glucosamine is an important sugar for the synthesis of various natural substances, such as sugars, lipids (fats) and proteins.
There are several forms: glucosamine sulfate, glucosamine hydrochloride and N-acetylglucosamine.
Being an important precursor of essential components of joint cartilage (proteoglycans and glycosaminoglycans, GAGs), glucosamine helps to keep cartilage intact, a tissue that acts as a cushioning cushion protecting the joint ends of the bones from friction.
In "osteoarthritis and" arthritis the cartilage is usually thinned or torn.
Glucosamine is also a component of keratin sulfate and hyaluronic acid, which are also present in the joint cartilage and in the fluid that lubricates the joints (synovial).
As the sulfate group is important for cartilage production, glucosamine sulfate is believed to be more effective than other types of glucosamine that do not contain it.
It is produced from shellfish shells or from the fermentation of wheat, or synthesized in the laboratory.
In Italy, glucosamine sulphate is indicated for the treatment of primary and secondary arthrosis (or osteoarthritis) and is available as a medicinal product obtainable upon presentation of a repeatable medical prescription (class C).It is usually taken by mouth and the recommended daily dose is 1500 milligrams (mg) in three doses.
Glucosamine sulfate, alone or in combination with chondroitin and / or other components, such as methylsulfonylmethane (MSM), is also available as a dietary supplement, a form that does not require a prescription and generally has lower dosages than those present in the preparations. prescribable.
In the form of a supplement it is widely used for the treatment of osteoarthritis and, more generally, to alleviate pain and joint stiffness.
It should be considered that different supplements, of different brands, may contain different amounts of these compounds, even far below the pharmacologically active dose, and this can greatly influence the effectiveness of the treatment.
Glucosamine can also be found in the form of an ointment, although there is no evidence that it can be absorbed by the skin.
Although various properties are attributed to it, including that of strengthening the joints and helping to preserve the structure and degree of elasticity of the cartilage, the European Food Safety Authority (EFSA) does not give specific indications for glucosamine-based products. , as there is insufficient scientific evidence to justify a cause-and-effect relationship between the intake of glucosamine and the maintenance of 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 much more limited.
Undesirable (side) effects and contraindications
When taken in the recommended amounts, glucosamine sulfate is well tolerated.
Reported undesirable effects (side effects) are very rare, however oral use of glucosamine sulfate can cause nausea, heartburn, constipation, drowsiness, skin reactions, headache.
Furthermore, since glucosamine-based products often derive from shellfish shells, the supplement could cause an allergic reaction in people with shellfish allergies.
Glucosamine could worsen asthma and it is advisable not to use it in case of known or presumed hypersensitivity to the active ingredient.
Interactions with some drugs have also been reported, in particular glucosamine could reduce the efficacy of paracetamol or increase the effect of anticoagulants.
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 a health claim related to glucosamine and maintenance of normal joint cartilage pursuant to Article 13 of Regulation (EC) No 1924/2006. EFSA Journal. 2012; 10: 2691
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
Kucharz EJ, Kovalenko V, Szántó S, Bruyère O, Cooper C & Reginster JY.A review of glucosamine for knee osteoarthritis: why patented crystalline glucosamine sulfate should be differentiated from other glucosamines to maximize clinical outcomes. Current Medical Research and Opinion. 2016; 32: 997
Mayo Clinic. Glucosamine (English)
National Institutes of Health (NIH). National Center for Complementary and Integrative Health (NCCIH). Glucosamine and Chondroitin for Osteoarthritis (English)
Humanitas research Hospital. Glucosamine