Allergic reactions, such as worsened asthma and swelling under the skin, have been reported with glucosamine use. Avoid in people with asthma.
Avoid in people with a known allergy or sensitivity to glucosamine sulfate or its parts. Glucosamine comes from shrimp, crab, and other shellfish, and should be avoided if allergic or sensitive to shellfish or iodine. Some glucosamine from specific manufacturers (Schiff®, Weider Nutrition Group, Salt Lake City, UT; Cargill Acidulants Regenasure®, Eddyville, Iowa Falls, IA) may have low levels of shrimp allergen and may be safe for allergic people.
Side Effects and Warnings
Glucosamine is likely safe when taken by mouth in studied doses (500 milligrams three times daily up to 90 days or 1,500 milligrams once daily up to six months) for a short time by healthy adults. Glucosamine sulfate is likely safe when injected into the joint at recommended doses for up to six weeks (not available in the United States).
Glucosamine is possibly safe when taken by mouth in recommended doses for up to three years. Doses of up to 3 grams daily and higher have been used in people with osteoarthritis.
Use cautiously in women who are, or plan to become, pregnant, or are breastfeeding. Use cautiously in children under 18 years old.
Drowsiness or sedation may occur. Glucosamine may also cause insomnia. Use caution if driving or operating heavy machinery.
Use cautiously when taking recommended doses over a long time period or if injected into the muscle. Use cautiously if using doses higher than those recommended. Use cautiously in people with low blood platelet counts, as glucosamine may interact with antibodies.
Use cautiously in people who have asthma, kidney disorders, active peptic ulcer disease, depression, skin conditions, or in people who need to restrict potassium intake.
Use cautiously in people who are at risk for cataracts, or in older people who have dry eyes. Glucosamine may cause increased cataract risk or dry eyes.
Use cautiously in people taking agents that increase the flow of urine.
Glucosamine may increase the risk of bleeding. Caution is advised in people with bleeding disorders or taking drugs that may increase the risk of bleeding, such as vitamin K antagonists (warfarin). Dosing adjustments may be necessary.
Glucosamine may affect blood pressure. Caution is advised in people with high blood pressure or heart conditions, or those taking drugs or herbs and supplements that affect blood pressure. Glucosamine may cause abnormal heart rate and palpitations.
Glucosamine may affect insulin resistance and/or blood sugar levels. Caution is advised in people with diabetes or low blood sugar, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.
Avoid using glucosamine-chondroitin supplements that contain Chinese skullcap. Liver damage has been reported with use of the Chinese skullcap contained in the Move Free® Advanced dietary supplement.
Avoid use with methylsulfonylmethane in children due to a potential link with autisim.
Avoid in people with a known allergy or sensitivity to glucosamine sulfate or its parts. Glucosamine comes from shrimp, crab, and other shellfish, and should be avoided if allergic or sensitive to shellfish or iodine.
Glucosamine may also cause anorexia, back or neck pain, changes in levels of creatine phosphokinase (enzyme found in heart, brain, and skeletal muscle), blood urea nitrogen, or creatine levels, constipation, coughing, diarrhea, dizziness, dry mouth, ear inflammation, a feeling of heaviness in the stomach, fluid accumulation, gas, headache, heartburn, increased blood lipids, increased growth rate of fingernails, indigestion, liver problems, muscle problems, nausea, stomach pain, toughened nails, upper abdominal tenderness, and vomiting.
Pregnancy and Breastfeeding
Use cautiously in women who are or plan to become pregnant, or those who are breastfeeding, due to lack of evidence.
Adults (18 years and older)
Note: Full benefit of glucosamine may take up to one month in some people. Glucosamine hydrochloride may provide more glucosamine than the glucosamine sulfate salt form.
To treat bone diseases (Kashin-Beck disease), 480 milligrams of glucosamine hydrochloride has been taken by mouth three times daily for six months, as well as 750 milligrams of glucosamine hydrochloride by mouth twice daily for six weeks.
To treat circulation problems (chronic venous insufficiency), Perclar® has been taken by mouth at doses of 48 milligrams, 72 milligrams, or 96 milligrams.
To treat high cholesterol, 1,500 milligrams of glucosamine, 1,527 milligrams of glucosamine sulfate (equivalent to 1,200 milligrams glucosamine), or 750 milligrams glucosamine hydrochloride (equal to 625 milligrams glucosamine) has been taken by mouth daily for up to 14 weeks.
To treat knee osteoarthritis, 300-500 milligrams of glucosamine sulfate or 480 milligrams of glucosamine hydrochloride has been taken by mouth three times daily for up to 12 weeks.
To treat low back pain, 1500 milligrams of glucosamine has been taken by mouth daily for six months. Additionally, 3 milliliters of glucosamine sulfate cream or 3 milliliters of glucosamine sulfate have been given through the skin via iontophoresis (using electricity to deliver the drug) or massaged into the skin for 15 minutes, three times weekly for four weeks.
To treat multiple sclerosis, 1000 milligrams daily of glucosamine sulfate has been taken by mouth for six months.
To treat osteoarthritis (general), 1000-2000 milligrams daily of glucosamine, glucosamine sulfate, or glucosamine hydrochloride in the form of tablets, capsules, or crystalline powder has been taken by mouth for up to 18 months. Up to 400 milligrams of glucosamine has also been injected into the joint, vein, or muscle for varying durations.
To treat rheumatoid arthritis, 420 milligrams of Teoremac® has been taken by mouth daily for 14 days.
Children (under 18 years old)
Glucosamine is not suggested in children, due to lack of data. Research suggests that there may be a link between autism and methylsulfonylmethane (MSM), which is often marketed with glucosamine. However, there is still a lack of information. Doses of 3-6 grams of N-acetyl-glucosamine have been used to treat inflammatory bowel disease in children.
Interactions with Drugs
Glucosamine may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as vitamin K antagonists (warfarin, Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
Glucosamine may affect insulin and blood sugar levels. Caution is advised when using medications that may affect blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
Glucosamine may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood, and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.
Glucosamine may also interact with acetaminophen; agents applied to the skin; agents eliminated by the kidneys; agents for the stomach or intestines; agents that increase sun sensitivity; agents that may increase urine flow; alcohol; anticancer agents; antidepressants; anti-hemorrhage agents; caffeine; chitosan; doxorubicin; etoposide; nicotine; nonsteroidal anti-inflammatory drugs (NSAIDs); pain relievers; rosiglitazone; teniposide; thiazolidinediones.
Interactions with Herbs and Dietary Supplements
Glucosamine may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
Glucosamine may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.
Glucosamine may affect insulin and blood sugar levels. Caution is advised when using herbs or supplements that may affect blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
Glucosamine may also interact with anticancer herbs and supplements; antidepressants; anti-hemorrhage herbs and supplements; antioxidants; avocado or soybean oils or extracts; bromelain; celadrin; Chinese skullcap; chondroitin sulfate; fish oil; ginger; green-lipped mussel extract; herbs and supplements applied to the skin; herbs and supplements eliminated by the kidneys; herbs and supplements for the stomach or intestines; herbs and supplements that increase sun sensitivity; herbs and supplements that may increase urine flow; Lindera aggregata; manganese; pain relievers; potassium; vitamin C.