Glucosamine Side Effects

by on July 18, 2012


The most common side effects of glucosamine are diarrhea, heartburn, nausea, and stomach upset. These symptoms are typically mild and diminish quickly as the body adjusts to the medication but if they persist or become bothersome you should report them to a doctor.

Common Glucosamine Side Effects

The most frequently occurring side effects of Glucosamine include:

  • Diarrhea
  • Heartburn
  • Nausea
  • Stomach upset

The side effects listed above usually do not require medical attention as they will commonly diminish when your body adjusts to the medication. Your doctor may also be able to advise you of ways to reduce or prevent these common side effects from occurring. However, if any persist or become bothersome you should notify your doctor to discuss alternative solutions.

Serious Glucosamine Side Effects

An allergic reaction can occur with glucosamine. If you experience any of the following symptoms indicating an allergic response, get emergency medical help right away.

  • Difficulty breathing
  • Tightness of the chest
  • Rash, hives, itching
  • Swelling of the face, lips, mouth, or tongue

Other side effects can occur while taking glucosamine that are not indicative of an allergic reaction but are still very serious. If you experience any of the following side effects, contact your doctor immediately.

  • Drowsiness
  • Insomnia
  • Headache
  • Loss of appetite
  • Vomiting
  • Constipation
  • Palpitations
  • Fever
  • Increase in blood pressure
  • Increase in heart rate

Existing Medical Conditions

Glucosamine may alter certain tests that are done to monitor diabetes; it may elevate blood sugar and insulin and also may adversely affect hemoglobin A1c tests. The exact effect that glucosamine has on diabetic conditions is not clear at this time; some research states the interaction is not risky. However, to avoid potential risks it is important to closely monitor blood sugar levels while taking this supplement. One report linking an asthma attack to glucosamine use has yet to be validated; the connection remains unknown but caution should be used by people with asthma when taking this supplement.

Individuals who have an allergy to shellfish should use great caution when taking glucosamine, as many supplement forms are made from shellfish. In order to find out for certain what your supplement is made from, you should contact the manufacturer; many glucosamine products are not required to be labeled with this information.


Glucosamine is not regulated by the FDA which means that many of the potential effects and benefits of this drug remain unknown. Women who are pregnant or may become pregnant should not use glucosamine. There is not enough information on this drug to determine the effect it may have on an unborn child. Women who are breastfeeding should not use any type of glucosamine as it may pass through breast milk and the effects on a newborn are not known at this time. Children should not take glucosamine; the possible effects of this supplement on them have not been studied.


In rare cases the combination of glucosamine and chondroitin has been linked to an increase in temperature, blood pressure, and heart rate as well as palpitations. Because this response was not commonly reported and glucosamine is not a regulated drug, the seriousness of these side effects is not known. If you experience any of the above listed reactions contact your doctor to discuss solutions or alternative treatment options.

Other Medications

It is important to tell your doctor about all medication that you take prior to beginning a new one; this includes all over the counter, prescription, and herbal medications. If you take any of the following medications, you should not take glucosamine unless you are under doctor supervision.

  • Anti-clotting and anti-platelet medications such as warfarin, Clopidogrel, and Ticlid
  • Vitamin E
  • Red clover
  • Garlic
  • Ginkgo biloba
  • Antimitotic chemotherapy medications

Antimitotic chemotherapy medications are used to slow the growth of tumors by decreasing the rate with which the cells copy; glucosamine may interfere with this slowing process. Anti-clotting and anti-platelet medications as well as all the herbal supplements above can increase bleeding by slowing down blood clotting; when these drugs are taken with glucosamine, the slowing effect may be further decreased.

Glucosamine may be beneficial in treating different types of arthritis and osteoarthritis as well as several other conditions. Because this drug is not regulated by the FDA it is unlikely that all the potential risks and benefits are known at this time. Women who are pregnant or breastfeeding should not use glucosamine until more is known about it. If you experience any serious or bothersome side effects while taking this drug, contact your doctor right away.