MSG and Warfarin

Publication Date: 
Fri, 04/01/2016
By: Alere Staff

Monosodium glutamate, or MSG, is a flavor-enhancing food additive that is used in many foods that we see or eat practically every day. These foods include many Asian foods as well as fast foods and commercially packaged food products like chips, crackers, soups and soup mixes, lunch meats and salad dressings.1 MSG was found in 1908 when a Japanese professor named Kikunae Ikeda was able to extract an amino acid called glutamate from seaweed broth.1,2 He determined that this was what gave the soup its savory umami flavor. Umami, known as the “fifth taste”, comes from this broad category of compounds called glutamates that occur naturally in foods like mushrooms, parmesan cheese and fermented soybean products. Umami is said to enhance other flavors by giving them depth and fullness.1 Once Ikeda had isolated this flavor-enhancing compound, he filed a patent to produce MSG, a synthetic version, and commercial production of MSG started the next year.2

Today, the flavor of MSG is not extracted and crystallized from seaweed broth. Instead it is produced during the fermentation of starch, sugar beets, sugar or molasses. The fermentation process is similar to that used to make foods like yogurt, vinegar and wine.2 The glutamate in MSG is chemically the same as the original. In fact, our bodies metabolize both sources of glutamate the same way.

MSG and Warfarin

MSG has been a food additive for many decades. While there is no evidence that MSG specifically interacts with warfarin, people have found that consuming too much MSG can cause various side effects including headaches, nausea, dizziness, skin rash, numbness and lethargy. Due to these reports, the FDA labeled the symptoms “MSG Symptom Complex” and did further research into the additive.

Researchers found no definitive evidence of a link between MSG and the reported symptoms to the FDA. While they acknowledged that a small percentage of people may have short-term reactions, the symptoms were usually minor and did not require treatment.Thus the FDA has classified MSG as a food ingredient that is “generally recognized as safe” and requires that the use of MSG be included on the label.3 The FDA does not require a label to specify that products naturally contain monosodium glutamate, but the foods cannot have the label “No MSG” or “No added MSG” on their packaging.2

In general, it is always best to speak with your doctor regarding any diet concerns and interactions with your medication. 

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  1. Alfaro, Danilo. What is MSG? (Monosodium Glutamate). Retrieved March 3, 2016 from the website:
  2. U.S. Department of Health and Human Services. Questions and Answers ion Monosodium glutamate (MSG) Jul 22, 2014. Retrieved from the website:
  3. Zeratsky, K. RD, LD. Healthy Lifestyle: Nutrition and Healthy Eating. Mayo Clinic. Mar. 13, 2015. Retrieved from the website: