Glucosamine Sulfate and Warfarin

Publication Date: 
Mon, 07/25/2016
By: Alere Staff


Vitamins and mineral supplements may seem like a healthy alternative to either over-the-counter medications or prescriptions. When it comes to joint pain and conditions like osteoarthritis, some people have turned to a supplement of glucosamine sulfate to ease their pain instead of other pain medications. For a patient on warfarin, this can appear to be a healthier option to other NSAIDs known to cause interactions with warfarin. However, is a supplement like glucosamine sulfate a healthier choice?


What is Glucosamine Sulfate? 

Glucosamine sulfate is a naturally-occurring element found in the human body and in other living creatures. It is used by the human body to produce the thick fluid that surrounds joints as well as other substances involved in building tendons, ligaments and cartilage.1 While glucosamine sulfate can also be produced within a lab for supplements, there are products that use glucosamine sulfate harvested from the shells of shellfish.1 

Taken by mouth, glucosamine sulfate supplements are most known for helping with joint pain and stiffness associated with a condition called osteoarthritis.1 In osteoarthritis, the cartilage around joints breaks down and becomes thinner resulting in more joint friction. It is believed that taking glucosamine sulfate can either increase cartilage and fluid surrounding prone joints or help to prevent the initial breakdown of both substances.1 While some researchers hope that glucosamine sulfate might be able to slow the processes involved in osteoarthritis, they find that it might not work well for a more severe, long-standing case of osteoarthritis or for people who start it at older ages or are heavier.1 

Other uses for glucosamine sulfate include helping with glaucoma, weight loss, joint pain caused by drugs, interstitial cystitis (a bladder condition), jaw pain, general knee joint pain, back pain, multiple sclerosis and HIV/AIDS. Glucosamine sulfate is also in some skin creams that are used for arthritis pain. However, there is no definitive research that using the supplement can help with these conditions or if pain will be decreased.1 

Glucosamine Sulfate and Warfarin 

While the idea of taking a natural supplement for joint pain may sound ideal, if you are a patient on warfarin, glucosamine sulfate is not recommended. Studies have shown that patients who are on warfarin and take glucosamine sulfate run the risk of having a higher INR and an increased risk of bleeding or bruising.2 The Federal Drug Administration (FDA) and World Health Organization (WHO) have done studies that show an increased risk of bleeding events associated with patients who take supplements containing glucosamine sulfate. These studies also show that when patients reduced their supplement dosage their INR usually returned to a normal therapeutic INR range.2  Patients who are on warfarin should speak with their healthcare provider if they are thinking about starting a supplement with glucosamine sulfate. It is also important to do your research on your supplements as some may not be labeled correctly, containing more glucosamine sulfate than stated.


  1. U.S. National Library of Medicine. Glucosamine and Warfarin. Medline Plus. Updated February 17, 2016. Retrieved from the website:
  2. Knudsen, JF, et al. Potential Glucosamine-Warfarin Interaction Resulting in Increased International Normalized Ratio: Case Report and Review of the Literature and MedWatch Database. Pharmacotherapy. 2008 Apr;28(4):540-8.