There are different forms of glucosamine including glucosamine sulfate, glucosamine hydrochloride, and N-acetyl glucosamine. These different chemicals have some similarities, but they may not have the same effects when taken as a dietary supplement. Most of the scientific research on glucosamine has involved glucosamine sulfate.
Some glucosamine products are not labeled accurately. In some cases, the amount of glucosamine actually in the product has varied from none to over 100% of the amount stated on the product's label. Some products have contained glucosamine hydrochloride when glucosamine sulfate was listed on the label.
Glucosamine sulfate and glucosamine hydrochloride are most commonly used for osteoarthritis. Glucosamine is also used for many other conditions, but there is no good scientific evidence to support these uses.
How does it work ?
Joints are cushioned by the fluid and cartilage that surround them. In some people with osteoarthritis, the cartilage breaks down and becomes thin. This results in more joint friction, pain, and stiffness. Researchers think that taking glucosamine supplements may either increase the cartilage and fluid surrounding joints or help prevent breakdown of these substances, or maybe both.
Uses & Effectiveness
Likely Effective for
- Osteoarthritis. Most research shows that taking glucosamine sulfate can provide some pain relief for people with osteoarthritis, especially those with osteoarthritis of the knees. For some people, glucosamine sulfate might work as well as over-the-counter and prescription pain medications such as acetaminophen or ibuprofen. But pain medications work quickly, while glucosamine sulfate can take 4-8 weeks before it provides pain relief. Also, people who take glucosamine sulfate often still need to take pain medications for pain flare-ups.
There are several kinds of glucosamine products. The research showing the most benefit is for products that contain glucosamine sulfate. Products that contain glucosamine hydrochloride do not seem to work as well unless they are taken in combination with other ingredients. Many products contain glucosamine with chondroitin, but there is no good evidence that these products work any better than glucosamine sulfate by itself.
Glucosamine sulfate does not seem to prevent people from getting osteoarthritis.
Insufficient Evidence for
- Joint pain caused by drugs called aromatase inhibitors (aromatase inhibitor-induced arthralgias). Early research suggests that taking a combination of glucosamine sulfate and chondroitin sulfate in two or three divided doses daily for 24 weeks reduces pain in women taking drugs that lower estrogen levels for early stage breast cancer.
- Heart disease. People who take glucosamine might have a lower risk of developing heart disease. But it's unclear what dose or form of glucosamine might work best. It's also unclear if this lower risk is from glucosamine or from following healthier lifestyle habits.
- Depression. Early research shows that taking glucosamine hydrochloride for 4 weeks might improve symptoms of depression in some people with depression.
- Diabetes. People who take glucosamine might have a lower risk of developing diabetes. But it's unclear what dose or form of glucosamine might work best. It's also unclear if this lower risk is from glucosamine or from following healthier lifestyle habits.
- High levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia). Early research suggests that glucosamine hydrochloride does not affect cholesterol or triglyceride levels in people with high cholesterol.
- Long-term swelling (inflammation) in the digestive tract (inflammatory bowel disease or IBD). There is some early evidence that N-acetyl glucosamine taken by mouth or rectally might decrease symptoms of IBD in children with Crohn disease or ulcerative colitis.
- A disorder that affects the bones and joints, usually in people with selenium deficiency (Kashin-Beck disease). Early evidence shows that taking glucosamine hydrochloride along with chondroitin sulfate reduces pain and improves physical function in adults with this condition. Taking glucosamine hydrochloride alone might work as well as over-the-counter pain medications.
- Knee pain. Early research shows that taking 1500 mg of glucosamine sulfate daily for 28 days does not reduce knee pain in athletes following a knee injury. But it does seem to improve knee movement. There is some early evidence that glucosamine hydrochloride might relieve pain for some people with frequent knee pain.
- Multiple sclerosis (MS). Early research shows that taking glucosamine sulfate by mouth daily for 6 months might reduce the relapse of multiple sclerosis.
- Recovery after surgery. Early research shows that taking glucosamine sulfate does not improve function, pain, and performance in male athletes who had surgery to fix a torn ACL. The ACL is a ligament that holds the knee in place during movement.
- Rheumatoid arthritis (RA). Early research shows that taking glucosamine hydrochloride might reduce pain but not the number of swollen and painful joints.
- Stroke. Early research has found that people who take glucosamine might have a slightly lower risk of having a stroke. But it's unclear what dose or form of glucosamine might work best. But it is unclear if this lower risk is from glucosamine or from healthier lifestyle habits.
- A group of painful conditions that affect the jaw joint and muscle (temporomandibular disorders or TMD). Early research disagrees on whether glucosamine sulfate reduces pain in people with osteoarthritis of the jaw joint.
- Aging skin.
- Back pain.
- Non-cancerous growths in the large intestine and rectum (colorectal adenoma).
- Death from any cause.
- Joint pain.
- Painful bladder syndrome (Interstitial cystitis).
- Wound healing.
- Other conditions.
When applied to the skin: N-acetyl glucosamine is POSSIBLY SAFE when used for up to 10 weeks.
When given as an enema (rectally): N-acetyl glucosamine is POSSIBLY SAFE when used in doses of 3-4 grams daily.
When given as a shot: Glucosamine sulfate is POSSIBLY SAFE when injected into the muscle as a shot twice weekly for up to 6 weeks.
Special Precautions and Warnings
Asthma: There is one report linking an asthma attack with taking glucosamine. It is not known for sure if glucosamine was the cause of the asthma attack. Until more is known, people with asthma should be cautious about taking products that contain glucosamine.
Diabetes: Some early research suggested that glucosamine might raise blood sugar in people with diabetes. But more recent and more reliable research now shows that glucosamine does not seem to affect blood sugar control in people with type 2 diabetes. Glucosamine appears to be safe for most people with diabetes, but blood sugar should be monitored closely.
Glaucoma: Glucosamine might increase the pressure inside the eye and could worsen glaucoma. If you have glaucoma, talk to your healthcare provider before taking glucosamine.
High cholesterol: Some early research suggested that glucosamine may increase cholesterol levels. But more recent and reliable research now shows that glucosamine does not seem to increase cholesterol levels.
High blood pressure: Some early research suggested that glucosamine may increase insulin levels. But more recent and reliable research shows that glucosamine does not increase blood pressure. To be on the safe side, monitor your blood pressure closely if you take glucosamine sulfate and have high blood pressure.
Shellfish allergy: There is some concern that glucosamine products might cause allergic reactions in people who are sensitive to shellfish. Glucosamine is produced from the shells of shrimp, lobster, and crabs. Allergic reactions in people with shellfish allergy are caused by the meat of shellfish, not the shell. But some people have developed an allergic reaction after using glucosamine supplements. It is possible that some glucosamine products might be contaminated with the part of the shellfish meat that can cause an allergic reaction. If you have a shellfish allergy, talk to your provider before using glucosamine.
Warfarin (Coumadin) interacts with GLUCOSAMINE
Warfarin (Coumadin) is used to slow blood clotting. There are several reports showing that taking glucosamine with or without chondroitin increase the effect of warfarin (Coumadin) on blood clotting. This can cause bruising and bleeding that can be serious. Don't take glucosamine if you are taking warfarin (Coumadin).
Do not take this combination
Medications for cancer (Antimitotic chemotherapy) interacts with GLUCOSAMINE
Some medications for cancer work by decreasing how fast cancer cells can copy themselves. Some scientists think that glucosamine might increase how fast tumor cells can copy themselves. Taking glucosamine along with some medications for cancer might decrease the effectiveness of these medications for cancer.
Some of these medications are etoposide (VP16, VePesid), teniposide (VM26), and doxorubicin (Adriamycin).
Be cautious with this combination
Acetaminophen (Tylenol, others) interacts with GLUCOSAMINE
There is some concern that taking glucosamine sulfate and acetaminophen (Tylenol, others) together might affect how well each works. But more information is needed to know if this interaction is a big concern.
Medications for diabetes (Antidiabetes drugs) interacts with GLUCOSAMINE
There has been concern that glucosamine sulfate might increase blood sugar in people with diabetes. There was also the concern that glucosamine sulfate might decrease how well medications used for diabetes work. However, research now indicates that glucosamine sulfate probably does not increase blood sugar in people with diabetes. Therefore, glucosamine sulfate probably does not interfere with diabetes medications. To be cautious, if you take glucosamine sulfate and have diabetes, monitor your blood sugar closely.
Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.
Be watchful with this combination
- For osteoarthritis: Glucosamine SULFATE 1500 mg once daily or 500 mg three times daily, either alone or together with 400 mg of chondroitin sulfate two or three times daily, has been used for up to 3 years.
CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.
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