Don't confuse N-acetyl glucosamine with other forms of glucosamine, such as glucosamine hydrochloride or glucosamine sulfate. They may not have the same effects.
Read glucosamine product labels carefully for their content. Most glucosamine products contain glucosamine sulfate or glucosamine hydrochloride. Although glucosamine sulfate and glucosamine hydrochloride are marketed together in combination products with N-acetyl glucosamine, there haven't been any human studies that have evaluated these combinations for treating osteoarthritis.
You may also see chitosan as an ingredient in some glucosamine products. Chitosan is a form of N-acetyl glucosamine that has been chemically altered.
N-acetyl glucosamine is used for osteoarthritis, diabetes, aging skin, knee pain, and inflammatory bowel disease (IBD), but there is no good scientific evidence to support these uses.
Uses & Effectiveness
Insufficient Evidence for
- Aging skin. Early research shows that applying a cream containing 2% N-acetyl glucosamine and 4% niacinamide to the face decreases dark spots caused by aging and sun exposure. It's unclear if applying a cream containing only N-acetyl glucosamine would have the same effect.
- 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. Other forms of glucosamine include glucosamine hydrochloride and glucosamine sulfate. It's also unclear if this lower risk is from glucosamine or from following healthier lifestyle habits.
- 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. Other forms of glucosamine include glucosamine hydrochloride and glucosamine sulfate. It's also unclear if this lower risk is from glucosamine or from following healthier lifestyle habits.
- 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's disease or ulcerative colitis.
- Knee pain. Early research shows that taking N-acetyl glucosamine along with chondroitin sulfate does not relieve pain in middle-aged and older adults with long-term knee pain.
- Stroke. 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. Other forms of glucosamine include glucosamine hydrochloride and glucosamine sulfate. It's also unclear if this lower risk is from glucosamine or from following healthier lifestyle habits.
- 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.
Special Precautions and Warnings
Asthma: Researchers aren't sure why, but glucosamine might make asthma worse in some people. If you have asthma, use caution when trying N-acetyl glucosamine.
Diabetes: Some early research suggested that glucosamine might raise blood sugar in people with diabetes. However, more reliable research indicates that glucosamine does not seem to significantly affect blood sugar control in people with type 2 diabetes. As long as you routinely monitor your blood sugar, you can probably take glucosamine, including N-acetyl glucosamine, safely.
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.
Surgery: N-acetyl glucosamine might affect blood sugar levels and might interfere with blood sugar control during and after surgery. Stop taking N-acetyl glucosamine at least 2 weeks before a scheduled surgery.
Warfarin (Coumadin) interacts with N-ACETYL GLUCOSAMINE (NAG)
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 (Chemotherapy) interacts with N-ACETYL GLUCOSAMINE (NAG)
There is some concern that N-acetyl glucosamine might decrease the effectiveness of some medications for cancer. But it is too soon to know if this interaction occurs.
Medications for diabetes (Antidiabetes drugs) interacts with N-ACETYL GLUCOSAMINE (NAG)
There has been concern that glucosamine might increase blood sugar in people with diabetes. There was also the concern that glucosamine might decrease how well medications used for diabetes work. However, research now indicates that glucosamine probably does not increase blood sugar in people with diabetes. Therefore, glucosamine probably does not interfere with diabetes medications. To be cautious, if you take N-acetyl glucosamine 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 cautious with this combination
Acetaminophen (Tylenol, others) interacts with N-ACETYL GLUCOSAMINE (NAG)
There is some concern that taking glucosamine 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.
Be watchful with this combination
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.
This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version. © Therapeutic Research Faculty 2018.