May 5, 2020 / 7:11 PM / a month ago

Partly false claim: Vaccines contain toxic levels of aluminum, polysorbate 80, yeast and other substances

A viral image on social media makes the claim that vaccines contain toxic levels of a range of substances. While the substances listed are present in certain vaccines, medical research suggest the levels are not harmful to the public.

Reuters Fact Check. REUTERS/Axel Schmidt

Under the heading “Vaccine Ingredients” the image lists the following ingredients and risks associated with each: “formaldehyde (toxic chemical, used in embalming), aluminum (toxic to the brain), gelatin (mashed up animal parts), urea (waste from human urine), potassium phosphate (used for fertilizer), human albumin (different kinds of human blood), polysorbate 80 (can cause infertility, toxic chemical), 2-phenoxyethanol (used for antifreeze), yeast protein (a fungus) and monosodium L-glutamate (causes diabetes & weight-gain)” ( here ; here ).

One image is accompanied by text that reads: “This is disgusting what they put in vaccines and convince you it’s good for you.” This claim on social media contains a mix of accurate and inaccurate information.


Reuters recently fact-checked a claim about the flu vaccine containing toxic levels of formaldehyde ( here ). The formaldehyde in vaccines poses no documented safety risks like the ones listed in the post on social media.


Aluminum can be found in several vaccines including DTaP and Hepatitis A ( here ).

The U.S. Centers for Disease Control and Prevention (CDC) writes that aluminum, a naturally occurring metal also present in nature, has been used safely in vaccines for decades. Aluminum salts act as vaccine adjuvants, or ingredients used to help stimulate a stronger immune response in the body. The CDC says, “adjuvanted vaccines can cause more local reactions (such as redness, swelling, and pain at the injection site) and more systemic reactions (such as fever, chills and body aches) than non-adjuvanted vaccines.” It also notes, however, that “in all cases, vaccines containing adjuvants are tested for safety and effectiveness in clinical trials before they are licensed for use in the United States, and they are continuously monitored by CDC and FDA once they are approved.” ( here )

The Children’s Hospital of Philadelphia notes that adjuvants allow “lesser quantities of the vaccine and fewer doses”, by stimulating the body’s immune response. It adds that, “the quantities of aluminum present in vaccines are low and are regulated by the Center for Biologics Evaluation and Research (CBER).”   ( here )


Gelatin is commonly found in some measles, mumps, rubella (MMR), typhoid and yellow fever vaccines, while urea is less common, but can be found in dengue and varicella vaccines ( here ).

The CDC notes that in addition to the antigens from viruses or bacteria contained in vaccines, there are also small amounts of other inactive ingredients known as excipients. Some excipients are known as stabilizers, or ingredients used “to keep the vaccine potent during transportation and storage” ( here ). Gelatin and urea are two such excipients.

The Vaccine Knowledge Project (VKP) managed by the Oxford Vaccine Group at the University of Oxford states that gelatin “derived from pigs is used in some live vaccines as a stabiliser to protect live viruses against the effects of temperature. Gelatine in vaccines is highly purified and hydrolysed (broken down by water), so it is different from the natural gelatine used in foods” ( here ). Its “vaccine ingredients” page does note that there have been a small number of documented cases of allergic reactions to vaccines containing gelatin (about one case per 2 million).

The VKP also states that urea, a harmless organic compound found in the body, is also sometimes used as a stabilizer in vaccines. Urea, also known as carbamide, “occurs not only in the urine of all mammals but also in their blood, bile, milk, and perspiration” as proteins are broken down by normal bodily functions ( here ).

It is therefore true that gelatin and urea are sometimes contained in vaccines as stabilizers, but to call them “mashed up animal parts” and “waste from human urine” is misleading.


Salts based on potassium phosphate can commonly be found in different kinds of influenza vaccines ( here ).

They are “common and harmless” acidity regulators, according to the Vaccine Knowledge Project ( here ). “As well as keeping the pH balance,” the VKP states, “they also help to keep the fragments of active ingredient suspended in the water, so that they do not settle out.”

Potassium phosphate can be present in plant fertilizer. Its role centers around providing and helping a plant store nutrients ( here ). It is also present in many foods, acting as a storing agent. While in large doses it can cause harm, the U.S. Food and Drug Administration (FDA) categorizes dipotassium phosphate as "generally recognized as safe" (GRAS)  ( here ).

It is true that potassium phosphate salts are used in vaccines but they are only present in small quantities and pose no credible safety concerns.


The CDC includes “human serum albumin”— an abundant protein found in human blood plasma — as an excipient found in vaccines against smallpox and rabies( here ).

The VKP also recognizes the use of human serum albumin as a preservative or stabilizer in vaccines, usually listed as an inactive ingredient ( here ).

A 2003 study in the Academy of American Pediatricians’ journal Pediatrics states that human serum albumin is contained in certain MMR vaccines. The publication states: “because human serum albumin is derived from human blood there is a theoretical risk that it might contain infectious agents. However, the FDA requires that human serum albumin be derived from blood of screened donors and be manufactured in a manner that would eliminate the risk of transmission of all known viruses. The result is that no viral diseases have ever been associated with the use of human serum albumin.” ( here )

It is therefore true that human serum albumin is contained in some vaccines and this stems from human plasma, but no viral diseases have been associated with its use.


According to the CDC, polysorbate 80 is an excipient commonly found in vaccines for influenza, Hepatitis B, HPV, and meningococcus ( here ).

The VKP states that polysorbate 80 is an emulsifier commonly used in food and drinks ( here ). According to Medical News Today, polysorbate 80 is “used in the food industry in ice creams, gelatin desserts, barbecue sauce, and pickled products. In vaccines, it helps other components remain soluble.” ( here )

Although some studies have raised safety concerns related to reproductive problem ( here ) an expert group at the European Medicines Agency has categorized the danger of polysorbate 80 as “very low” ( here ).

It is therefore true that polysorbate 80, a common emulsifier in the food industry, can be used in vaccines to keep components soluble, but health experts have determined risk of exposure to the substance as low. To call it a “toxic chemical” is therefore misleading.


According to the FDA, 2-Phenoxyethanol is an organic chemical compound that is sometimes used in cosmetics and antiseptics. The FDA states that the compound “is also currently used as a preservative in one FDA-approved available vaccine, Ipol, for the prevention of polio, at a concentration of 0.5%.” ( here )

A 2010 study entitled “The relative toxicity of compounds used as preservatives in vaccines and biologics” found that the relative toxicity of the preservative 2-phenoxyethanol on human cells was less than alternative preservatives used in vaccines ( here ). The study, however, also noted that: “none of the compounds commonly used as preservatives in US licensed vaccine/biological preparations can be considered an ideal preservative, and their ability to fully comply with the requirements of the US Code of Federal Regulations (CFR) for preservatives is in doubt.”

The National Library of Medicine has compiled case reports of some vaccine reactions stemming from the presence of 2-phenoexyethanol ( here ). Reuters was otherwise unable to corroborate a list of comprehensive safety concerns related to the substance when administered through vaccines.


Yeast protein can be found among excipient ingredients for Hepatitis A, Hepatitis B, and HPV vaccines ( here ).

The Children’s Hospital of Philadelphia states that Hepatitis B vaccines are “made using baker’s yeast and residual quantities of yeast proteins are contained in the final product.” It also notes that severe allergic reactions have been reported by recipients of the Hepatitis B vaccine, although an allergy to yeast is not confirmed to be the cause of these reactions ( here ).

The CDC warns that the “Hepatitis B vaccine is not recommended for anyone who is allergic to yeast, or to any other component of the vaccine” and it can pose the risk of a severe allergic reaction to those with hyper-sensitivity to yeast ( here , here ).


Monosodium L-glutamate is a common excipient in vaccines for adenovirus, influenza, and varicella ( here ).

The Military Health System writes that monosodium L-glutamate is “a stabilizer that protects vaccines from heat, light, humidity or acidity while they are stored.”  ( here )

The National Library of Medicine states that monosodium L-glutamate is the “optically active” form monosodium glutamate, commonly known as MSG and used as a flavoring agent ( here ). The FDA considers that MSG is “generally recognized as safe” although people may consider themselves sensitive to its ingestion ( here ).

It is therefore true that monosodium L-glutamate is used in vaccines as a stabilizer, but this substance is recognized as safe.


Partly false claim. Some vaccines contain small amounts of formaldehyde, aluminum, gelatin, urea, potassium phosphate, human albumin, polysorbate 80, 2-phenoxyethanol, yeast protein and monosodium L-glutamate but the presence of these substances does not pose a credible safety concern.

This article was produced by the Reuters Fact Check team. Read more about our work to fact-check social media posts here

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