Function of Glucosamine in life

Glucosamine (C₆H₁₃NO₅) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the most abundant monosaccharides.Produced commercially by the hydrolysis of shellfish exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat, glucosamine has many names depending on country.^[2]

Although a common dietary supplement, there is little evidence that it is effective for relief of arthritis or pain, and is not an approved prescription drug.

Dietary supplement

Oral glucosamine is a dietary supplement and is not a prescription drug.^[3][5] Glucosamine is marketed as a supplement to support the structure and function of joints, and the marketing is targeted to people suffering from osteoarthritis.^[3][5]

Commonly sold forms of glucosamine are glucosamine sulfate,^[3] glucosamine chondroitin, glucosamine hydrochloride,^[4] and N-acetylglucosamine.^[3][2] Of the three commonly available forms of glucosamine, only glucosamine sulfate is given a “likely effective” rating for treating osteoarthritis.^[3] Glucosamine is often sold in combination with other supplements such as chondroitin sulfate and methylsulfonylmethane.^{[citation needed]}

Glucosamine, along with commonly used chondroitin, is not routinely prescribed to treat people who have symptomatic osteoarthritis of the knee, as there is insufficient evidence that this treatment is helpful.^[6][7]

As is common with heavily promoted dietary supplements, the claimed benefits of glucosamine are based principally on clinical and laboratory studies. Clinical studies on glucosamine efficacy are divided, with some reporting relief from arthritic pain and stiffness, while others report no benefit above placebo.^[3][8][7][9]

As of 2015, there is no evidence that consumption of glucosamine by sport participants prevents or limits joint damage after injury.^[10]

Adverse effects and drug interactions

Glucosamine with or without chondroitin elevates the international normalized ratio (INR) in individuals who are taking the blood thinner, warfarin.^[3][11] It may also interfere with the efficacy of chemotherapy for treating cancer symptoms.^[3]

Adverse effects are mild and infrequent and may include stomach upset, constipation, diarrhea, headache, and rash.^[12]

Since glucosamine is usually derived from the shells of shellfish, it may be unsafe for those with shellfish allergy.^[13] Many manufacturers of glucosamine derived from shellfish include a warning that those with a seafood allergy should consult a healthcare professional before taking the product.^[14] Alternatively, non-shellfish-derived forms of glucosamine are available.^[15]

Another concern has been that the extra glucosamine could contribute to diabetes by interfering with the normal regulation of the hexosamine biosynthesis pathway,^[16] but several investigations found no evidence that this occurs.^[17][18] Other studies conducted in lean or obese subjects concluded that oral glucosamine at standard doses does not affect insulin resistance.