Processed Free Glutamic Acid (MSG): An Overview

The Basics

Pinpointing MSG as a Reaction Trigger

About the People who Sell the Product

Misleading and Deceptive Use of "No MSG" on Product Labels

What You Might Do


Adrienne Samuels, Ph.D.

Truth in Labeling Campaign

850 DeWitt Place - 20B

Chicago, IL60611


November, 2010


The Basics


        MSG-sensitivity is a sensitivity to free glutamic acid that occurs in food as a consequence of manufacture or fermentation. We refer to this free glutamic acid as processed free glutamic acid (MSG). All protein contains glutamic acid, primarily bound to other amino acids, but only when glutamic acid has been freed from protein due to manufacture or fermentation before it is eaten do people experience MSG-sensitivity reactions, provided that they ingest amounts that exceed their individual tolerance levels. Some unadulterated protein may have minute amounts of free glutamic acid associated with it, but MSG-sensitive people generally report no adverse reactions following ingestion of unadulterated protein. The source of the MSG (soy, corn, etc.) appears to be irrelevant.

        MSG is manufactured through two basic processes: 1) a process called bacterial fermentation wherein glutamic acid is secreted through the cell walls of selected genetically engineered bacteria that are generally grown on a carbohydrate medium; and 2) a process of protein breakdown wherein glutamic acid is freed from protein through a manufacturing process such as the use of chemicals (hydrolysis), enzymes (enzymolysis), or fermentation. With some exceptions, the FDA requires that ingredients, MSG-containing ingredients included, must be labeled by their common or usual names. The name "monosodium glutamate" is reserved for the ingredient that is a 99% pure combination of glutamic acid, sodium, and moisture. The names of most other MSG-containing ingredients won't even give consumers a clue to the fact that the ingredients contain MSG. "Monosodium glutamate," "monopotassium glutamate," "autolyzed yeast," "hydrolyzed soy protein," and "sodium caseinate" are examples of ingredients that always contain MSG.

        Under certain circumstances, products that contain MSG may be used as ingredients in other products without mention of the original MSG-containing products. The label descriptors flavor and flavoring, often preceded by the word “natura”, are considered by the FDA to be proprietary ingredients, and as such, food industry companies are not required to list their ingredients. In recent years, The FDA has required the disclosure of the food ingredients “monosodium glutamate and hydrolyzed protein used in flavor or flavoring. However, this requirement has been ineffective since, to our knowledge, the FDA has not tested flavors or flavorings for the presence of MSG. MSG-containing products such as broth, bouillon, and stock, when used as ingredients in other products, do not have to disclose the fact that the broth, bouillon, or stock contains MSG.

        Use of MSG in American food has increased in the last 40 years and is still growing. MSG is found in most soups, salad dressings, processed meats, basted meat and poultry, frozen entrees, ice cream, and frozen yogurt; in some crackers, bread, canned tuna; and in most "low fat" foods to make up for flavor lost when fat is reduced or eliminated.

        In 1969, Schaumburg et al. determined that approximately 30% of our population suffered adverse reactions when fed MSG in an ordinary diet.(1) Reif-Lehrer(2) and Kenney and Tidball(3) confirmed their findings. Those studies were challenged by Kerr et al. in a 1979 glutamate industry sponsored study.(4) Kerr et al. found that 43 per cent of respondents reported one or more unpleasant symptoms associated with eating, but concluded that only 1.8% of the population might be sensitive to MSG. To accomplish this, Kerr et al. decreed that the only true symptoms of MSG-sensitivity (called "Chinese restaurant syndrome"), were "burning, tightness, and numbness," experienced simultaneously, that commenced between 10 minutes and 2 hours after the start of a meal, and lasted 4 hours or less. Kerr et al. had to ignore all other reported symptoms, even migraine headache,(5) in order to come up with this 1.8% figure.

        Given increased use of MSG since 1969, we would now expect more than 40% of the population to suffer adverse reactions to MSG.



Pinpointing MSG as a Reaction Trigger

MSG-sensitive people report reactions ranging from simple skin rash to severe depression and life-threatening physical conditions. Two or more reactions occurring together, or one following another, are not uncommon. The amount of MSG ingested may play a role in the specific nature of a reaction. The intensity of a reaction appears to be affected by alcohol ingestion and/or exercise just prior to, or immediately following, MSG ingestion.


Diagnosis of MSG sensitivity is extremely difficult:

        -None of the symptoms of MSG-toxicity are caused exclusively by MSG. Most, if not all, could be caused by various physical conditions as well as by other food additives or environmental triggers.

        -Some people eat MSG and react immediately. Some react as late as 48 hours after ingesting MSG. Of help in diagnosis is the fact that each person typically reacts within one predictable time frame each time after ingesting MSG, and typically one experiences the same reaction each time one reacts, providing he or she did not ingest alcohol or exercise prior to or just following exposure to MSG.

        -Reactions are dose related. Some people cannot tolerate even the smallest amount of MSG. Others tolerate single small amounts, but react to MSG when they ingest a half gram or more in any one meal. Others may ingest five grams or more, without evidencing a reaction. Canned soups analyzed some time ago each contained about a half gram of MSG.A “Accent” brand Amonosodium glutamate@ lists a single serving of Amonosodium glutamate@ as .5 grams of Amonosodium glutamate.@ We know of no MSG-containing product that contains as much as 3 grams of MSG per serving.

        -The adverse effects of MSG ingestion may be cumulative. People have reported eating small amounts of MSG once a week without experiencing reactions, while having reactions when those same products were consumed two days or more in a row.

        - MSG is very often hidden in food. Hiding MSG makes recognition of MSG so complex and confusing that MSG-sensitive people have a great deal of difficulty identifying it. If a person reacted after eating something known to contain MSG, he might suspect that MSG was the culprit. But if that person had the same reaction after eating something that contained MSG, but did not disclose the fact on the label, he or she would very likely question their original suspicion. Until all sources of MSG are easy to identify through disclosure on labels, evaluation of possible MSG reactions will be difficult.

        - Difficulty in diagnosing MSG-sensitivity is compounded by the industry practice of illegally advertising "No MSG," "No MSG Added," or "No Added MSG" on labels when products do contain MSG.

        - Diagnostic tools available to the physician in diagnosing MSG sensitivity are limited to a procedure called Achallenge.@ In a physician's office, an appropriate dose (or doses) of MSG would be given to the patient, and provision would have to be made for both restricting the patient's contact with other potential reaction triggers and observing reactions delayed by as much as 48 hours. As an alternative, physician and patient, working together, may be able to identify, or rule out, MSG as a reaction trigger through analysis of a patient food diary. Restricting intake to totally unprocessed food and drink for three weeks, then reintroducing items, one at a time, may help identify offending sources of MSG. If at all possible, food and drink that have not been sprayed, fertilized, or waxed with MSG-containing products should be avoided. 



About the People who Sell the Product

        There is considerable evidence to suggest that consumption of MSG places humans at risk, with the greatest risk faced by children.(6)

        On the other hand, studies designed, implemented, and/or supported by the glutamate industry that claim to support the industry claim that MSG is “safe are generally questionable. All data we have seen from The Glutamate Association, the International Glutamate Technical Committee (IGTC), the International Food Information Council (IFIC), and their sponsors and agents, come from studies that are badly flawed.(7)

        We are aware of no person, institution, or agency that has claimed that MSG is "safe," that does not have close ties to food and/or drug industries, or that has not been remunerated by them. In 1992, the FDA appointed both Andrew G. Ebert, Ph.D., IGTC chairman, and Kristin McNutt, Ph.D., paid spokesperson for the IGTC, to the FDA Food Advisory Committee. Ebert is (or was) also an official "Observer" at the World Health Organization. In 1992, the FDA funded "an independent study" conducted by the Federation of American Societies for Experimental Biology, with Expert Panel members including at least four people with ties to the glutamate industry. Steve Taylor, Ph.D., who is (or was) The Institute for Food Technologists' Communicator on the subject of MSG has been a paid IGTC spokesperson for years.

        Trade associations that represent glutamate industry interests include IFIC and the International Life Sciences Institute (ILSI). IFIC actively fought the presentation of a "60 Minutes" segment on MSG in 1991, and presently offers material that pretends to demonstrate that MSG is safe. The Encyclopedia of Associations says that IFIC represents the interests of the glutamate industry. Yet, on Internet, we found IFIC listed as "independent."

IFIC's packet on MSG includes names of speakers who will attest to the safety of MSG. Named are Steve Taylor, Ph.D., Darly Altman, M.D., S. Allan Bock, M.D., Susan S. Schiffman, Ph.D., John D. Fernstrom, Ph.D., Jonathan H. Pincus, M.D., L. Jack Filer, M.D., Ph.D., Fergus M. Clydesdale, Ph.D., Richard J. Wurtman, M.D., and Dr. Sanford A. Miller. The American Academy of Allergy and Immunology has developed materials jointly with IFIC or IFIC's foundation. Their brochure entitled "Understanding Food Allergy" includes such false information as "Whenever MSG is added to food, it is listed on the label as monosodium glutamate." The IFIC brochure, "What You Should Know about Monosodium Glutamate," which "has been reviewed favorably by the American Academy of Family Physicians Foundation,@ states not only that MSG is safe, but that MSG is safe for children. The FDA has also developed a brochure jointly with IFIC that states, in part, "Whenever MSG is added to food, it is listed on the label as monosodium glutamate."

        In 1994, IFIC commissioned a review of the book Excitotoxins: The Taste that Kills written by Russell L. Blaylock, M.D. Blaylock warned that MSG probably contributes to neurodegenerative disease such as ALS, Alzheimer's disease, and Parkinson's disease. The review was done for IFIC by Jonathan Pincus, M.D., who, it would appear, did not read Blaylock's book. Pincus' research has, in part, been supported by ILSI. ILSI has also provided grant money to The Food Allergy Network. Dr. Steve Taylor, mentioned earlier, is a member of The Food Allergy Network Medical Advisory Board. The Food Allergy Network is a nonprofit organization that claims as members both the FDA and the U.S. Department of Agriculture.

        Universities, medical schools, and individual researchers that represent the interests of the glutamate industry are discussed more fully on the Web at   



Misleading and Deceptive Use of "No MSG" on Product Labels

        Manufacturers are acutely aware that, in general, consumers would prefer not to have the food ingredient monosodium glutamate in their food.(9) Some have responded by using "clean labels," i.e., labels that do not reveal that the food contains MSG. Others illegally label foods that do not contain the food ingredient monosodium glutamate as "No MSG," "No MSG Added," or "No Added MSG," even though their products contain MSG as a component of an ingredient other than monosodium glutamate.

        Label statements "No MSG," "No MSG Added," or "No Added MSG" have been deemed to be deceptive and misleading under section (403)(a)(1) of the Federal Food, Drug, and Cosmetic Act when the label also lists any ingredient that contains free glutamic acid.(10-11) (Emphasis added.)Such labeled products are considered to be mislabeled by the FDA. Thus, to advertise "No MSG," "No MSG Added," or "No Added MSG" when there is MSG in a product is illegal.

        At one time, the FDA regulated the illegal use of the term "No MSG Added," with both a Regulatory Letter and threat of seizure and injunction in case of non-compliance.(12) It would appear that because food processors and manufacturers have become comfortable in the knowledge that the FDA will do nothing to regulate the deceptive and misleading use of these terms, labels sporting such claims have proliferated. While from time to time the FDA sends a message to the food industry that the illegal labels are indeed illegal, the United States Department of Agriculture actually approves labels of meat and poultry products that claim "No MSG Added," or "No Added MSG" even when products contain free glutamic acid.

        The number of products/ingredients/substances that contain MSG is not finite, i.e., new products that contain MSG are invented and/or renamed daily. To keep track of them would be virtually impossible. Moreover, MSG can be freed from protein during processing or manufacture given appropriate conditions. Any ingredient that contains a bit of protein can be broken down during manufacture, resulting in some free amino acids, if hydrochloric acid, enzymes, heat, and/or any other substances or condition that causes glutamic acid to be freed from its host protein are present. Thus, it is impossible to know with certainty that there is, or is not, MSG in a product by reading the names of the ingredients put into it. The only way to determine whether or not there is MSG in a product is to measure the amount of MSG in its end product.

        There are tests for measuring free glutamic acid. The AOAC Official Methods of Analysis (1984) gives one method. There are others.

        Clearly, since it is deceptive and misleading to claim "No MSG," "No MSG Added," or "No Added MSG" on a product label when free glutamic acid is present as a natural constituent of an ingredient, or otherwise, any such claim must be substantiated.  Those making such claims should be able to demonstrate, through valid tests for free glutamic acid content, that there is zero free glutamic acid in their end product.  Only if there is zero free glutamic acid in a product can one legitimately claim that there is no MSG.  The burden of proof for a claim about the absence of MSG must lie with those making the claim.



In the past, flavors and flavorings that are preceded by the word artificial were considered to be safe for MSG-sensitive people.  However, at this time, a new product, Senomyx, has been developed to enhance the flavor of food, as does MSG.  The product, now on the market, appears to work neurologically in the same manner as does MSG.  Its use in a product will not be disclosed in that it will be labeled as, or included in, the food ingredient labeled artificial flavor or artificial flavoring.


What You Might Do

It is suggested that you spread the word of the toxicity of MSG and direct people to our Web site ( for additional information regarding MSG. Also, write to your congressperson and senators in Washington. If you are MSG-sensitive, advise them of your reaction(s) to MSG and how difficult it is for you to avoid MSG. Ask that they require that all processed foods, supplements, and drugs, when introduced and whenever there is a change in ingredients be analyzed for free glutamic acid.” Also, if free glutamic acid is found to be present, ask that it be mandated that its presence be disclosed on the label as MSG, with the amount present stated in milligrams.





1. Schaumburg, H.H., Byck, R., Gerstl, R., and Mashman, J.H. Monosodium L-glutamate: its pharmacology and role in the Chinese restaurant syndrome. Science 163: 826-828, 1969.

2. Reif-Lehrer, L.  A questionnaire study of the prevalence of chinese restaurant syndrome.  Fed Proc 36: 1617-1623, 1977.

3. Kenney, R.A. and Tidball, C.S.  Human susceptibility to oral monosodium L-glutamate.  Am J Clin Nutr 25: 140-146, 1972.

4. Kerr, G.R., Wu-Lee, M., El-Lozy, M., McGandy, R., and Stare, F.  Food-symptomatology questionnaires: risks of demand-bias questions and population-biased surveys.  In: Glutamic Acid: Advances in Biochemistry and Physiology,  Filer, L. J., et al., Eds.  New York: Raven Press, 1979. 

5. Food and Drug Administration (FDA) Health Hazard Evaluation Board (Monitoring System). Report on all adverse reactions in the Adverse Reaction Monitoring System. Memorandum from Sean F. Altekruse, DVM, MPH, Acting Chief and Ms. Donna M. Gray, Technical Information Specialist, Epidemiology Branch, FDA. 2/28/94. 

6. Blaylock, R.L. Excitotoxins: The Taste that Kills. Santa Fe: Health Press, 1994. 

7. Samuels, A. Monosodium L-glutamate: a double-blind study and review. Letter to the Editor. Food and Chemical Toxicology 33: 69-78, 1995. 

8. Samuels, A. The Toxicity/Safety of Processed Free Glutamic Acid (MSG): A Study in Suppression of Information.  Accountability in Research 6: 259-310, 1999. 

9. National Food Merchandiser March, 1992. Page 16. 

10. Janice F. Oliver, Director, Office of Regulatory Guidance, Center for food Safety and Applied Nutrition, FDA. Letter to Jack L. Samuels dated December 5, 1991. 

11. Food and Drug Administration. Backgrounder August 31, 1995. 

12. April 10, 1990 FDA Regulatory Letter to Fantastic Foods, Inc., Novato, CA.