Contrary to viral misinformation, cow feed additive Bovaer shows no safety concerns for consumers

In early December 2024, posts questioning the safety of a cow feed additive called Bovaer went viral across social media platforms.

Claims related to this product took multiple forms. Many users raised concerns about the safety of certain compounds in Bovaer. Others encouraged people to drink raw (unpasteurized) milk instead, a dangerous trend that has been linked to food poisoning outbreaks.

Some posts referred to Bovaer as “toxic” or “a poison” and argued that dairy companies were hiding Bovaer’s labels in their products. Others called on people to boycott milk brands using this additive. Finally, some users falsely associated Bovaer with Bill Gates or even linked the product to baseless depopulation conspiracy theories.

Misinformation and threats of a boycott were particularly widespread in the U.K. after the Danish dairy company Arla Foods announced in November 2024 that it would start trials of Bovaer in the U.K. The virality of the misinformation circulating in the U.K. led Bovaer’s manufacturer to issue a statement addressed to farmers, retailers, and consumers, dispelling common misconceptions about the product’s safety.

Below, we review in detail why claims that Bovaer is unsafe for cattle or people consuming food products derived from cows treated with Bovaer are incorrect and misleading.

What is Bovaer and why is it used?

BovaerⓇ 10 is a cow’s feed additive that aims to mitigate the environmental footprint of beef and dairy products by reducing cows’ release of methane. The product has been researched and developed for nearly 15 years.

Ruminant animals like cows feed on grass and other fibrous plant materials that are hard to digest. To break down these materials and absorb their nutrients, ruminants have a specialized stomach populated with microbes that ferment partially digested food to facilitate digestion. The fermentation process produces methane as a byproduct, which the cow releases as flatulence or burps.

In one year, a single cow can produce 70 to 120 kilograms of methane, a greenhouse gas 28 times more potent than carbon dioxide. Methane is the second largest contributor to greenhouse emissions from human activity after carbon dioxide^[1], and the livestock sector is one of its greatest sources. Globally, cattle livestock raised for meat production release 231 billion pounds (more than 100 million tons) of methane into the atmosphere each year. As explained in a 2021 AGU Advances study, “Livestock production represents a third of the global anthropogenic methane emissions nowadays, and the emissions are expected to keep increasing in the future”^[1].

Strategies for reducing methane emissions from livestock therefore play an important role in action plans to mitigate global warming. The Food and Agriculture Organization of the United Nations recommends that countries cut methane emissions, particularly from livestock, by 30% by the year 2030. Methane-reducing food additives like Bovaer are one of the strategies being researched by scientists.

The active ingredient in Bovaer is 3-nitrooxypropanol (3-NOP), an alcohol that stops the last reaction needed to produce methane in the cow’s stomach^[2]. This active ingredient is diluted in propylene glycol and silicic acid^[3], two food additives generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA).

According to Bovaer’s manufacturing company, supplementing the cow’s daily feed with Bovaer reduces methane emissions by 30% in dairy cattle and up to 45% in beef cattle, on average.

Two studies involving different research groups—one independent and one funded by Bovaer’s manufacturer—confirm this effect, showing that 3-NOP consistently reduced methane emissions from dairy cows by 28 to 33%^[4,5].

The European Union authorized Bovaer as an additive for cattle nutrition in April 2022. Since then, the product has been authorized and marketed in more than 68 countries worldwide, including the U.S., Canada, and the U.K.

Risks associated with handling concentrated Bovaer don’t apply to food products from treated animals

Some users questioned Bovaer’s safety based on a letter from the FDA to Elanco Animal Health Incorporated, Bovaer’s exclusive manufacturer and distributor in the U.S.

The letter contained a warning that Bovaer isn’t intended for human use. It added that 3-NOP “may damage male fertility and reproductive organs, is potentially harmful when inhaled, and is a skin and eye irritant”. Therefore, it cautioned people to wear protective equipment when handling this product.

Many posts shared the FDA letter implying that a product attached to such a warning couldn’t possibly be safe for cattle or the people who consume products derived from animals treated with this additive. However, this implication is misleading.

Oliver Jones, a professor of chemistry at the RMIT University, explained to the U.K.’s Science Media Centre:

“One can’t directly compare the everyday use of Bovaer and the potential risks from its use in concentrated form. For example, Bovaer is claimed to be an irritant to the eyes and skin and potentially harmful by inhalation, but common salt is also an irritant to the eyes and skin, and water is clearly potentially harmful by inhalation. Context is extremely important when assessing risk, but entirely missing from the social media videos on this topic.”

In other words, concentrated forms of 3-NOP are considered hazardous for people handling them, like workers involved in making Bovaer’s and, to a lesser extent, farmers. But this risk doesn’t apply to the product when used as a feed additive nor to the milk and meat from cows treated with it.

3-NOP is only toxic at doses much higher than those used to supplement cows

Commonly cited concerns about Bovaer’s safety involved DNA damage, cancer, and reproductive harm. Many posts cited 3-NOP as the chemical responsible for these alleged effects.

But assessments by regulatory agencies, including the European Food Safety Authority (EFSA) and the U.K. Food Standards Agency (FSA), found no safety concerns for consumers, cows, and the environment when Bovaer is used as directed.

Bovaer’s safety was extensively investigated in test tubes, rodent and human cells grown in the laboratory, and in rodents, dogs, goats, and cows. Because the EFSA conducted the most exhaustive assessment publicly available at the time of writing, we will focus on this report in this review.

The EFSA assessment noted several adverse effects of 3-NOP. First, while most tests showed no signs of 3-NOP damaging DNA, the possibility couldn’t be ruled out from the results of the experiments. Second, the researchers found no evidence that 3-NOP caused cancer, but they observed benign (non-cancerous) tumors in the intestines of female rats fed with high doses of 3-NOP for two years. Finally, 3-NOP also caused ovarian shrinkage in cows treated with twice the recommended dose for two months, and testicular shrinkage affecting sperm production in rats treated with high 3-NOP doses daily for three months.

These results may be the basis for the online claims. However, to understand what they actually mean for people consuming milk and meat from cows supplemented with Bovaer, we need to add some important context.

While some substances are toxic at any level, toxicity is generally a matter of the amount of exposure. In other words, it is the dose that makes the poison. So, the relevant question is: can consumers be exposed to toxic level of 3-NOP through the milk and meat of animals treated with Bovaer?

All of the toxic effects of 3-NOP were observed at very high doses, between 300 and 500 milligrams of pure 3-NOP per kilogram of body weight. No adverse effects were observed up to 100 milligrams of 3-NOP per kilogram of body weight per day. This value was used by the EFSA panel to establish the no observed adverse effect level (NOAEL), which determines the limit of toxicity.

Cows treated with Bovaer receive an even lower level of 3-NOP. The manufacturing company recommends a quarter teaspoon (about 1.5 grams) of Bovaer per animal and day, of which 3-NOP represents only 10.5% (about 0.15 grams). A cow with an average weight of 500 kilograms will, therefore, receive around 0.3 milligrams of 3-NOP per kilogram of body weight. This dose is approximately 1,000 times lower than the levels of 3-NOP associated with adverse effects in rats and hundreds of times lower than the NOAEL value established by the EFSA panel.

Ian Musgrave, a pharmacologist at the University of Adelaide, put the toxicity figures into perspective in an article for The Conversation. Based on the safety assessment data, Musgrave explained that a person of 70 kilograms would need to ingest 21 to 35 grams (around two tablespoons) of pure 3-NOP a day, every day, for weeks to reach a toxic level of exposure.

3-NOP doesn’t pass into milk and meat from cows; breakdown products are considered safe

The absorption, distribution, and breakdown of 3-NOP was evaluated in laboratory tests and in animals. The EFSA assessment noted that 3-NOP doesn’t accumulate but is “rapidly and almost entirely” broken down in the cow’s stomach. The results of the analyses show that 3-NOP is completely metabolized within 24 hours following its administration.

Furthermore, the analyses found no traces of 3-NOP in the milk and meat of animals treated with Boaver, regardless of the dose used. Therefore, 3-NOP doesn’t pose any risk to human health because consumers aren’t exposed to it.

But what about the products resulting from 3-NOP breakdown in the cow’s gut? Do they pose a risk to human health?

The EFSA assessment included the results of laboratory experiments and studies in rodents, goats, and cows showing that 3-NOP breaks down into several products. The main breakdown products are 1,3-propanediol, nitrogen compounds (nitrites and nitrates) that are incorporated into proteins, and carbon dioxide, which is exhaled. All these chemicals are normally present in the body and therefore considered non-toxic.

In addition, researchers identified 3-nitrooxy propionic acid (NOPA), which was further evaluated for safety.

NOPA showed no signs of damaging the DNA. However, it was considered responsible for testicular toxicity, which was considered specific for rats. But while NOPA was the major breakdown product of 3-NOP in rats, ruminants only produced it in very limited amounts.

The highest NOPA concentration found was 3.66 micrograms (one-millionth of a gram) per kilogram in cow milk. This value was detected in a single cow out of the 19 animals evaluated and milked several times a day throughout the two months of treatment duration. The concentrations in tissues were all below the limit of quantification (the lowest concentration at which the chemical can be reliably measured) of five micrograms per kilogram, regardless of the amount of 3-NOP the animal received.

Based on animal studies, the EFSA panel considered that the NOAEL identified for 3-NOP is also valid for NOPA. To this value, the panel added a margin of safety, also called uncertainty factor, of 100 to set an acceptable daily intake (ADI) in humans of one milligram of NOPA per kilogram of body weight. EFSA experts estimated that consumers’ exposure to NOPA through the milk from animals treated with Bovaer was at least 1,000 times below the ADI.

Because NOPA doesn’t damage DNA and human exposure is well below the safety values, the EFSA concluded that NOPA is of no safety concern for consumers.

Overall, the EFSA assessment concluded that Bovaer is effective in reducing cow methane emissions and can be considered safe in cows at the amount recommended. It added that the use of Bovaer under these conditions “is of no concern for consumer safety”. The FSA assessment arrived at the same conclusions.

Conclusion

Online claims suggesting that consuming food products from cows treated with the additive Bovaer causes health problems like DNA damage, cancer, and infertility are baseless. Different regulatory agencies that evaluated this supplement found no safety concerns for cows and consumers when Bovaer is used at the recommended dose.

Bovaer’s main ingredient, 3-NOP, is considered hazardous when handling it as a concentrate. However, this risk doesn’t apply to its use as a feed additive. While 3-NOP showed toxicity at high levels of exposure in animals, the amounts recommended for supplementing cows are much lower. Furthermore, 3-NOP is quickly broken down in the cow’s gut and doesn’t pass into the milk and the meat, so consumers aren’t exposed to it.

REFERENCES

• 1 – Chang et al. (2021) The Key Role of Production Efficiency Changes in Livestock Methane Emission Mitigation. AGU Advances.
• 2 – Duin et al. (2016) Mode of action uncovered for the specific reduction of methane emissions from ruminants by the small molecule 3-nitrooxypropanol. PNAS.
• 3 – EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) (2021) Safety and efficacy of a feed additive consisting of 3-nitrooxypropanol (Bovaer® 10) for ruminants for milk production and reproduction (DSM Nutritional Products Ltd). EFSA Journal.
• 4 – Hristov et al. (2022) Symposium review: Effective nutritional strategies to mitigate enteric methane in dairy cattle. Journal of Dairy Science.
• 5 – Kebreab et al. (2023) A meta-analysis of effects of 3-nitrooxypropanol on methane production, yield, and intensity in dairy cattle. Journal of Dairy Science.