Oral glucosamine is adietary supplement and is not aprescription drug in the United States.[4][6] Glucosamine is marketed as a supplement to support the structure and function of joints, and the marketing is targeted to people withosteoarthritis.[4][6]
Commonly sold forms of glucosamine are glucosamine sulfate,[4] glucosaminechondroitin, glucosamine hydrochloride,[5] andN-acetylglucosamine.[4][3] Of the three commonly available forms of glucosamine, only glucosamine sulfate is given a "likely effective" rating for treating osteoarthritis.[4] Glucosamine is often sold in combination with other supplements such aschondroitin sulfate andmethylsulfonylmethane.[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.[7][8]
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.[4][9][8][10]
As of 2015[update], there is no evidence that consumption of glucosamine by sport participants prevents or limits joint damage after injury.[11]
Adverse effects are mild and infrequent and may include stomach upset, constipation, diarrhea, headache, and rash.[13]
Since glucosamine is usually derived from the shells ofshellfish, it may be unsafe for those withshellfish allergy.[14] 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.[15] Alternatively, non-shellfish-derived forms of glucosamine are available.[16]
Another concern has been that the extra glucosamine could contribute to diabetes by interfering with the normal regulation of thehexosamine biosynthesis pathway,[17] but several investigations found no evidence that this occurs.[18][19] Other studies conducted in lean or obese subjects concluded that oral glucosamine at standard doses does not affectinsulin resistance.[20][21]
As the formation of glucosamine-6-phosphate is the first step for the synthesis of these products, glucosamine may be important in regulating their production; however, the way that the hexosamine biosynthesis pathway is actually regulated, and whether this could be involved in contributing to human disease remains unclear.[17]
Most glucosamine is manufactured by processingchitin from the shells ofshellfish including shrimp, lobsters, and crabs.[25] To meet the demands of vegetarians and others with objections to shellfish, manufacturers have brought glucosamine products to market made using fungusAspergillus niger and from fermenting corn.[16]
In the United States, glucosamine is not approved by theFood and Drug Administration (FDA) for medical use in humans.[30] Since glucosamine is classified as adietary supplement in the United States, evidence of safety is required by FDA regulations, but evidence of efficacy is not required so long as it is not advertised as a treatment for a medical condition.[31]
In 2004, the FDA declared there was insufficient evidence for supplement manufacturers to state that glucosamine was effective for treating arthritis, joint degeneration, orcartilage deterioration, a position remaining in effect as of 2018.[32][30]
In most of Europe, glucosamine is approved as a medical drug and is sold in the form of glucosamine sulfate.[33] In this case, evidence of safety and efficacy is required for the medical use of glucosamine and several guidelines have recommended its use as an effective and safe therapy forosteoarthritis.
The Task Force of the European League Against Rheumatism (EULAR) committee has granted glucosamine sulfate a level of toxicity of 5 in a 0-100 scale,[33] and recent OARSI (Osteoarthritis Research Society International) guidelines for hip and knee osteoarthritis indicate an acceptable safety profile.[34] By 2014, the OARSI did not recommend glucosamine for disease modification, and considered it "uncertain" for symptom relief, in knee osteoarthritis.[35]
In 2013, without admitting fault, manufacturer Rexall Sundown and NBTY agreed to pay up toUS$2 million to settle consumer claims related to the wording of certain claims on the packaging of glucosamine bottles sold atCostco under the Kirkland label.[36]
In August 2012, a class-action lawsuit was filed in New York claiming that 21st Century Healthcare, Inc. had falsely advertised that its "Glucosamine 750 Chondroitin 600 Triple Strength" dietary supplements would restore lost cartilage.[37] In April 2013, a San Diego man launched a proposed class-action lawsuit in California Federal Court accusing Nutramax Laboratories,Walmart andRite Aid of falsely advertising the effectiveness of glucosamine.[38]
Because glucosamine is a precursor forglycosaminoglycans, and glycosaminoglycans are a major component ofcartilage, research has focused on the potential for supplemental glucosamine to improve cartilage structure and alleviatearthritis, but there is little evidence fromclinical trials that it is effective for alleviating arthritis pain.[7][failed verification][9]
Two studies measured the concentrations of glucosamine in thesynovial fluid andplasma after oral administration of glucosamine sulfate to both healthy volunteers and people with osteoarthritis.[39][40]
In the first study, glucosamine sulfate was given to healthy volunteers in doses of 750, 1,500, or 3,000 mg once daily. In the second study, oral glucosamine sulfate capsules (1,500 mg) were given daily for two weeks to 12 people withosteoarthritis. Glucosamine concentrations in plasma andsynovial fluid increased significantly from baseline levels, and the levels in the two fluids were highly correlated. The authors interpreted that these levels could be biologically advantageous toarticular cartilage, but the levels are still ten to one hundred times lower than required to positively influence thecartilage (chondrocytes) to build new tissue.[41] Glucosamine sulfate uptake insynovial fluid may be as much as 20%, or it could be negligible, indicating no biological significance.[42]
Some studies have shown efficacy of glucosamine supplementation for dogs with osteoarthritis pain, particularly in combination with other nutraceuticals like chondroitin,[43][44] while others have not.[45] A trial of oral combination capsules (glucosamine, chondroitin, and manganese ascorbate) in dogs with osteoarthritis found no benefit on either gait analysis or subjective assessments by the veterinarian or owner.[45]
The use of glucosamine in equine medicine exists, but one meta-analysis judged extant research too flawed to be of value in guiding treatment of horses.[46]
A number of studies have measured the bioavailability of glucosamine after oral administration to horses. When given as a single oral dose (9 g) with or withoutchondroitin sulfate (3 g) to ten horses, glucosamine (hydrochloride) was detected in the blood with a maximum level of10.6±6.9 μg/mL at two hours after dosing.[47] Another study examined both the serum and the jointsynovial fluid after nasogastric (oral) or intravenous administration of 20 mg/kg glucosamine hydrochloride to eight adult horses.[48] Although joint fluid concentrations of glucosamine reached 9–15 μmol/L following intravenous dosing, it was only 0.3–0.7 μmol/L with nasogastric dosing. The authors calculated that these glucosamine synovial fluid levels achieved by the oral route were 500 times lower than that required to have a positive effect on the metabolism ofcartilage cells. A follow-up study by the same research group compared glucosamine sulfate with glucosamine hydrochloride at the same dose (20 mg/kg) in eight horses and found a higher fluid concentration with the sulfate preparation (158 ng/mL compared to 89 ng/mL one hour post oral dose).[49] They concluded that these highersynovial fluid levels obtained with the sulfate derivative were still too low to have a relevant biological effect onarticular cartilage.
A three-month trial of an oral dosage regime of a commercial preparation of glucosamine sulfate, chondroitin sulfate andmethylsulfonylmethane was performed in veteran horses with no effect on gait stiffness, with exercise alone in the control group being effective.[50] The intravenous use of a combination ofN-acetylglucosamine, pentosan polysulfate and sodium hyaluronate in horses with surgically-induced osteoarthritis saw improvements in X-ray changes to the cartilage but not histologically or in biochemical outcomes,[51] suggesting more evidence is needed for this combination and route of administration.
^DiNubile N (July 2018). "Glucosamine and Chondroitin Sulfate: What Has Been Learned Since the Glucosamine/chondroitin Arthritis Intervention Trial".Orthopedics.41 (4):200–207.doi:10.3928/01477447-20180511-06.PMID29771395.S2CID21707977.
^Scroggie DA; Albright A; Harris MD (July 2003). "The effect of glucosamine-chondroitin supplementation on glycosylated hemoglobin levels in patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized clinical trial".Archives of Internal Medicine.163 (13):1587–90.doi:10.1001/archinte.163.13.1587.PMID12860582.
^"UDP-N-acetylglucosamine Biosynthesis".Recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the Nomenclature and Classification of Enzymes by the Reactions they Catalyse. International Union of Biochemistry and Molecular Biology. 2002. Retrieved2012-09-10.
^Murray, Michael T. (2012)."Chapter 94: Glucosamine". In Pizzorno, Joseph E. Jr.; Murray, Michael T. (eds.).Textbook of natural medicine (4th ed.). Edinburgh: Churchill Livingstone. p. 790.ISBN9781437723335.
^Ledderhose G (1879). "Über Chitin und seine Spaltungs-produkte" [On chitin and its hydrolysis products].Zeitschrift für Physiologische Chemie.ii:213–227.
^Ledderhose G (1880). "Über Glykosamin".Zeitschrift für Physiologische Chemie.iv:139–159.
^W. N. Haworth; W. H. G. Lake; S. Peat (1939). "The configuration of glucosamine (chitosamine)".Journal of the Chemical Society:271–274.doi:10.1039/jr9390000271.
^Mroz PJ, Silbert JE (2004). "Use of 3H-glucosamine and 35S-sulfate with cultured human chondrocytes to determine the effect of glucosamine concentration on formation of chondroitin sulfate".Arthritis Rheum.50 (11):3574–9.doi:10.1002/art.20609.PMID15529373.
^Cohen MJ, Braun L (2007).Herbs & natural supplements: an evidence-based guide. Marrickville, New South Wales: Elsevier Australia.ISBN978-0-7295-3796-4.
^Gupta, R. C.; Canerdy, T. D.; Lindley, J; Konemann, M; Minniear, J; Carroll, B. A.; Hendrick, C; Goad, J. T.; Rohde, K; Doss, R; Bagchi, M; Bagchi, D (2012). "Comparative therapeutic efficacy and safety of type-II collagen (UC-II), glucosamine and chondroitin in arthritic dogs: Pain evaluation by ground force plate".Journal of Animal Physiology and Animal Nutrition.96 (5):770–7.doi:10.1111/j.1439-0396.2011.01166.x.PMID21623931.
^d'Altilio, M; Peal, A; Alvey, M; Simms, C; Curtsinger, A; Gupta, R. C.; Canerdy, T. D.; Goad, J. T.; Bagchi, M; Bagchi, D (2007). "Therapeutic Efficacy and Safety of Undenatured Type II Collagen Singly or in Combination with Glucosamine and Chondroitin in Arthritic Dogs".Toxicology Mechanisms and Methods.17 (4):189–96.doi:10.1080/15376510600910469.PMID20020968.S2CID36796044.
^abMoreau, M; Dupuis, J; Bonneau, N. H.; Desnoyers, M (2003). "Clinical evaluation of a nutraceutical, carprofen and meloxicam for the treatment of dogs with osteoarthritis".The Veterinary Record.152 (11):323–9.doi:10.1136/vr.152.11.323.PMID12665145.S2CID40196882.
^Pearson, W; Lindinger, M (2009). "Low quality of evidence for glucosamine-based nutraceuticals in equine joint disease: Review of in vivo studies".Equine Veterinary Journal.41 (7):706–12.doi:10.2746/042516409X424153.PMID19927591.
^Laverty, S; Sandy, J. D.; Celeste, C; Vachon, P; Marier, J. F.; Plaas, A. H. (2005). "Synovial fluid levels and serum pharmacokinetics in a large animal model following treatment with oral glucosamine at clinically relevant doses".Arthritis and Rheumatism.52 (1):181–91.doi:10.1002/art.20762.PMID15641100.
^Higler, M. H.; Brommer, H; l'Ami, J. J.; De Grauw, J. C.; Nielen, M; Van Weeren, P. R.; Laverty, S; Barneveld, A; Back, W (2013). "The effects of three-month oral supplementation with a nutraceutical and exercise on the locomotor pattern of aged horses".Equine Veterinary Journal.46 (5):611–7.doi:10.1111/evj.12182.PMID24011144.
^Koenig, T. J.; Dart, A. J.; McIlwraith, C. W.; Horadagoda, N; Bell, R. J.; Perkins, N; Dart, C; Krockenberger, M; Jeffcott, L. B.; Little, C. B. (2014). "Treatment of Experimentally Induced Osteoarthritis in Horses Using an Intravenous Combination of Sodium Pentosan Polysulfate,N-Acetyl Glucosamine, and Sodium Hyaluronan".Veterinary Surgery.43 (5):612–22.doi:10.1111/j.1532-950X.2014.12203.x.PMID24819506.
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