The Safety Concerns Over BHA, BHT, and ADA in the United States

Food additives are an integral part of the food supply. They extend shelf life, improve appearance, and enhance flavor. However, the regulations about what is a safe food additive and what is not keep changing. The latest under FDA scrutiny are BHA, BHT, and ADA, which are legal in the U.S. but heavily restricted in Europe due to safety concerns.

But what are they, and are they dangerous? Let’s break down the latest updates and the scientific evidence.

BHA and BHT

BHA stands for butylated hydroxyanisole, while BHT is butylated hydroxytoluene. Both are synthetic antioxidants widely used in the food industry to slow the rancidity of fats and oils caused by oxidation.

Both compounds significantly extend the shelf life of processed foods such as cereals, baked goods, snacks, and other packaged goods. They also help maintain the freshness, flavor, and color for extended periods.

Current regulatory status

Currently, the FDA classifies both BHA and BHT as ‘generally safe’ to use in food at regulated levels. However, in May 2025, the FDA announced that these additives are now subject to post-market assessment. This is part of a broader initiative to improve the regulation of food additives.

Safety concerns and scientific evidence

Several health concerns exist about BHA and BHT, primarily their endocrine-disrupting and carcinogenic potential.

Endocrine disruption

Concerns about these compounds affecting the endocrine system and hormone function have been raised.

In vitro studies have shown that BHA has weak estrogenic and anti-androgenic properties, while in vivo studies have found anti-estrogenic properties. However, a meta-analysis concluded that there is insufficient evidence about BHA’s hormonal effects.

The EU Scientific Committee of Consumer Safety (SCCS) has concluded that BHT does not raise significant endocrine disruption concerns when consumed in recommended concentrations.

Effects on the reproductive system

In rats, high doses of BHA cause mild underdevelopment and dysfunction of the reproductive system in both males and females. Changes in testosterone levels, sex organ weights, and sexual maturation were seen. However, no studies have been conducted in humans.

A mouse study found that BHT in high doses during pregnancy decreased maternal body weight during early pregnancy and negatively affected the uterine lumen. Estrogen and progesterone levels, as well as the receptors, were also affected. This study suggests that BHT negatively affects the female reproductive system; however, no studies have been done in humans.

Carcinogenic potential

The National Toxicology Program’s 15th report on carcinogens noted that dietary consumption of BHA caused benign and malignant tumors in the stomachs of rats, mice, and hamsters. It also caused liver cancer in adult fish when BHA was administered to larvae. The report concluded that there is not enough research or evidence to determine the relationship between BHA and human cancers.

In high doses, BHT has also shown tumor-promoting effects in animals, possibly due to its ability to induce liver enzymes. However, the SCCS review concluded that BHT concentrations permitted in cosmetic products do not pose significant cancer risks for humans. The key point is that the safety margins were established to consider the health concerns.

Microbiome disruption

At very high doses (ten times the recommended dose), BHA can decrease the number of beneficial bacteria of the Bacteroidota, Proteobacteria, Verrucomicrobiota, Actinobacteriota, Desulfobacterota I, and Firmicutes C phyla. The changes are small but significant. The study concluded that when BHA is consumed in recommended amounts, it is unlikely to significantly or permanently alter the gut microbiome.

Consumers have raised concerns about BHT's adverse effects on gut health, but no evidence supports this. Still, more sensitive individuals may find it disrupts their gut health.

Overconsumption toxicity

Animal and in vitro studies that have found adverse health effects have used excessive amounts of BHT and BHA. This suggests that high or frequent consumption may negatively affect health.

Furthermore, no studies have examined the combined effects of BHA, BHT, ADA, and other additives. Hence, it is unknown whether their potential adverse health effects are cumulative.

ADA

Azodicarbonamide (ADA) is a synthetic chemical and food additive primarily used as a whitening agent and dough conditioner in commercial bread making. It helps maintain a consistent texture and appearance of baked goods, ensuring each batch is nearly identical.

ADA is also used as a foaming agent in plastics manufacturing, which has led many to question its suitability for food use. In Europe, it is forbidden to add ADA to baked goods.

Current regulatory status

The FDA considers ADA safe to use and consume as long as it is within the specified limits. However, the regulations vary significantly worldwide and even across states. Texas legislators recently signed a law requiring a warning label on foods containing ADA in response to increasing concerns about the additive.

Safety concerns and scientific evidence

Several health concerns make people wary of ADA.

Respiratory issues

Occupational exposure to ADA, especially in plastic manufacturing, has been associated with respiratory issues such as eye/nose/throat irritation, cough, wheezing, chest tightness, and symptoms of chronic bronchitis.

A few cases of occupational asthma associated with ADA have also been reported.

Carcinogenic byproducts

ADA itself is not considered carcinogenic, but when heated to high temperatures during baking, it may break down into the carcinogenic byproducts semicarbazide and urethane.

Due to a lack of research, semicarbazide is regarded as a carcinogen in mice but not in humans. When a maximum amount of ADA is used, the urethane levels pose a small carcinogenic risk to humans, but not when used in smaller amounts.

Classicization concerns

There is a lack of consensus between experts and states on whether ADA is safe for human consumption. Some states are urging the compound to be banned as a food additive due to health concerns, while other authorities keep saying it is safe. This has resulted in fears of classifying ADA as safe and whether it should be classified as a carcinogen.

Recent regulatory developments

The U.S. regulatory landscape is undergoing significant changes. In May 2025, the FDA started a massive initiative to systematically review the safety of additives and chemicals in the food supply. BHA, BHT, and ADA are on the priority list for review.

This regulatory shift is meant to be a meaningful advance in customer protections, as most food additives have not been reviewed since their initial approvals decades ago.

The Environmental Working Group has even developed an interactive map to track state-level regulations and bans on chemicals. The initiative aims to provide consumers with comprehensive updates and transparency regarding regional variations in food additive laws and regulations.

Consumer perspective and industry response

Social media platforms like TikTok are the main drivers of consumer worries, as concerns about food safety and additives often get amplified and spread like wildfire. It sometimes even leads to public panic around ingredients, like in the case of ADA, despite the lack of scientific context.

Before giving in to the claims on social media, check The Center for Science in the Public Interest (CSPI), which maintains a Chemical Cuisine database that rates food additives from ‘safe' to ‘avoid.'

Manufacturers using BHA, BHT, ADA, and similar additives may need to reformulate their products due to rising public awareness and the nationwide re-evaluation of food additives. This transition requires balancing food safety, health, costs, and regulatory compliance and is likely to take a while.

Final thoughts

BHA, BHT, and ADA safety is a complex and evolving issue in the U.S. While deemed safe for humans, in high doses, they have been shown to cause adverse health outcomes in animals.

This has sparked numerous conversations revolving around the fact that these additives are in multiple products, and while each of them may contain a safe amount, what about the cumulative effect?

For now, focus on reading ingredient labels, seeking out products without controversial additives, and staying informed about emerging research. Lastly, do not believe everything you see on social media, especially the fear-mongering TikToks that make it seem like everything is trying to harm you.