Butylated hydroxytoluene, aka BHT, is a preservative and antioxidant found commonly in food and skincare products alike. While it might not be hard to find, it has garnered a controversial reputation over time—leading some people to wonder if it’s safe to use, or best to avoid altogether. 

As always, we’re here to answer any of your skincare questions—so we’ll break down what you need to know about BHT and its safety.

What is BHT? 

BHT is a synthetic chemical that acts as both a preservative and antioxidant in foods, cosmetics, and skincare products. This chemical is often included in creams and lotions because it works as an efficient stabilizer. It also has antioxidant benefits that help prevent the product from spoiling when it’s exposed to air.¹

How is BHT used in skincare? 

If you’re trying to develop your ideal skincare routine, it makes sense to dig into the ingredients of the products you’re using, and how these ingredients work. Here’s how BHT works in skincare.

BHT’s use as a stabilizing agent 

When you’re looking for skincare products, shelf life and consistency are important factors to consider. Products that contain BHT may last longer and also have a smoother texture.

BHT is often used as a stabilizer to help maintain the other active ingredients in skincare products. It’s a popular way to preserve the oil and fats found in cosmetics because it’s fat-soluble.² 

BHT’s role as an antioxidant 

When skincare products with potent ingredients are exposed to the air, they can get oxidized quickly. This means the oxygen in the air degrades the ingredients and makes the product change in color, texture, and odor. 

BHT helps prevent this problem because the oxygen in the air prefers to react with BHT as opposed to the other oils and ingredients making up a product.³ For this reason, many manufacturers choose to add BHT into their products.

It’s clear that BHT offers benefits, which is why it's so widely used. But here’s the question everyone’s asking: Is BHT safe?

Is BHT safe? 

A lot of research has gone into determining how safe BHT is, and if it leads to any significant adverse effects. A comprehensive report on the safety of BHT published in the International Journal of Toxicology concluded that BHT demonstrates “no significant irritation, sensitization, or photosensitization” in those who use this ingredient, according to currently available research.⁴

Since BHT is used at low concentrations in beauty products, it’s considered safe to use in cosmetic formulations.⁵ The FDA has approved BHT as a food additive in limited quantities in some foods as well.⁶

Additionally, the Cosmetic Ingredient Review Expert Panel concluded in 2002 that BHT is safe as used in cosmetic formulations. And with an update in 2019, they have determined that the maximum concentration of use in leave-on products remains the same as in 2002 (at 0.5%).⁷ 

Why is BHT often considered a controversial ingredient? 

Since research shows that BHT is safe, you might be wondering why it’s garnered a controversial reputation to begin with. That’s because BHT is often confused with another ingredient called butylated hydroxyanisole, aka BHA (not to be confused with BHAs, or beta hydroxy acids). BHA is also approved for use in cosmetics and food in limited amounts by the FDA.⁸ However, unlike BHT, BHA actually carries carcinogenic potential.⁹

What is the difference between BHT and BHA?

Both BHT and BHA are synthetic antioxidants commonly used in the food and cosmetics industry to preserve fats and oils and to prevent products from spoiling. However, there are some significant differences between the two:

Chemical structure

BHT and BHA are different chemical compounds. BHT is a derivative of toluene (a colorless liquid found naturally in oil).¹⁰ BHA is a man-made antioxidant that is almost completely synthetic.¹¹

Solubility

BHT is soluble in fats and oils, whereas BHA is soluble in fats, oils, and some other substances (such as propylene glycol, petroleum ether, chloroform, and 50% alcohol).¹² For this reason, BHT is primarily used in cosmetics and foods that contain fats and oils. BHA, on the other hand, is used in a wider range of cosmetics and foods, including baked goods, meats, and beverages.

Safety

Both BHT and BHA are considered safe to use by the FDA in small quantities. However, BHA has carcinogenic potential, whereas BHT does not.¹³

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PS. We did the homework so you don’t have to:

1. PubChem. Butylated Hydroxytoluene. National Center for Biotechnology Information. (2023, May 5).

2. The National Institute for Biological Standards and Control (NIBSC). BHT Datasheet. (n.d.).

3. The National Institute for Biological Standards and Control (NIBSC). BHT Datasheet. Ibid.

4. Lanigan, R.S., and Yamarik, T.A. Final report on the safety assessment of BHT(1). Int J Toxicol. (2002, n.d.).

5. Lanigan, R.S., and Yamarik, T.A. Final report on the safety assessment of BHT(1). Int J Toxicol. Ibid.

6. U.S. Food & Drug Administration. CFR - Code of Federal Regulations Title 21- BHT. (2023, January 17).

7. Cosmetic Ingredient Review. Safety Assessment of BHT as Used in Cosmetics. (2019, May 10).

8. U.S. Food & Drug Administration. CFR - Code of Federal Regulations Title 21- BHA. (2023, January 17).

9. National Toxicology Program. 15th Report on Carcinogens: Butylated Hydroxyanisole. U.S. Department of Health and Human Services. (2021, December 21).

10. PubChem. Toluene. National Center for Biotechnology Information. (2023, May 5).

11. Felter, S.P., et al. Butylated hydroxyanisole: Carcinogenic food additive to be avoided or harmless antioxidant important to protect food supply? Regulatory Toxicology and Pharmacology (April 2021).

12. National Toxicology Program. 15th Report on Carcinogens: Butylated Hydroxyanisole. U.S. Department of Health and Human Services. Ibid.

13. Lanigan, R.S., and Yamarik, T.A. Final report on the safety assessment of BHT(1). Int J Toxicol. Ibid.

14. U.S. Food & Drug Administration. CFR - Code of Federal Regulations Title 21- BHT. Ibid.

15. Lanigan, R.S., and Yamarik, T.A. Final report on the safety assessment of BHT(1). Int J Toxicol. Ibid.

Donna McIntyre is a board-certified nurse practitioner at Curology. She obtained her Master of Science in Nursing at MGH Institute of Health Professions in Boston, MA.

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Written by

Curology Team

Medically reviewed by

Donna McIntyre, NP-BC