Ingredient Watch List: Iodopropynyl Butylcarbamate, the Toxic Preservative

Iodopropynyl Butylcarbamate

Well here we are talking about the potential problems with synthetic preservatives again! Iodopropynyl butylcarbamate (IPBC) is a water-based preservative which—get this—was used originally in the wood and paint industries. It's now also used in some cosmetics and personal care products. However, even the cosmetic industry admits that this ingredient is toxic, and restrictions have been placed on its use.

Here's why you may want to watch out for this one.

If you're using products with this toxic preservative, you may find yourself scratching irritated skin.

What is Iodopropynyl Butylcarbamate?

IPBC is a preservative that helps prevent mold, bacteria, and other germs from spreading in creams, lotions, and other products. It was used for years in paints, primers, and coolants, and only more recently in cosmetic products, as it is effective against a wide variety of microorganisms. You're likely to find it in foundations, concealers, bronzers, self-tanners, eye shadows, mascaras, makeup removers, shampoos, conditioners, shaving creams, diaper creams, anti-itch and rash creams, bath soaks, body washes, hair dyes, lip balms, and moisturizers.

Is It Safe?

IPBC is a suspected gastrointestinal and liver toxin, and is thought to present risks to human reproduction and development, having been linked to the potential for reduced fertility and increased risk of pregnancy problems. It's a suspected teratogen, which means that it may increase the risk of birth defects.

The Environmental Protection Agency notes that there is limited evidence of gastrointestinal and liver toxicity with IPBC, and Japan's Standards for Cosmetics restrict its use in cosmetics. Even the Cosmetic Ingredient Review (CIR) has expressed concerns about toxicity with IPBC, and limits the use in cosmetics to concentrations less than or equal to 0.1%. They noted that at concentrations of 0.5% and above, it has the potential to irritate skin, and because of the dangers of inhaling the chemical, they recommend it not be used in products meant to be aerosolized.

The European Union goes even further to limit the use of the preservative in cosmetics at a maximum concentration of 0.02% in rinse-off products, and 0.01% in leave-on products, except in deodorant/antiperspirant products, where the limit is even lower—0.0075%.

Proven to Increase Risks of Contact Allergies

The other main problem with IPBC is that it can increase your risk for contact dermatitis—skin allergies. According to 2003 patch-test study, IPBC is one of the new allergens. In 2008, British doctors noted allergic dermatitis in cleansing wipes. In a 2002 study, researchers stated that, “As the use of this seemingly safe preservative becomes vast, an increased number of cases of IPBC-induced contact allergy is likely.”

As more consumers have become aware of the potential dangers in preservatives like parabens, companies are looking for alternatives. Rather than use natural preservatives that don't present potential dangers, however, they're turning to options like IPBC. As we find it in more and more products, we're seeing more and more allergies.

Typical symptoms of an allergy to IPBC include redness, swelling, itching, and fluid-filled blisters. It's important to be aware that the symptoms may not develop for several days after exposure to the ingredient. Patch tests can help you determine if you may suffer from an IPBC allergy.

Safer, More Nourishing Choices

To avoid this preservative, watch for the following on your products:

  • IBP
  • IPBC
  • Butyl-3-iodo-2-propynylcarbamate
  • Carbamic acid
  • Glycacil®

There are all sorts of natural alternatives to chemicals like these that don't subject you to health risks. These include thyme, vitamin E, vitamin C, and even lavender and rosemary. Plus these ingredients provide skin benefits on their own, as well as preserving the formula, so why would you use anything else?

Have you gotten rid of products with IPBC? Did you experience an allergy from it? Please share your story.

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Badreshia, S; Marks Jr, JG (2002). “Iodopropynyl butylcarbamate”. American journal of contact dermatitis 13 (2): 77–9. PMID 12022126.

Badreshia S, Marks JG Jr., “Iodopropynyl butylcarbamate,” Am J Contact Dermat. 2002 Jun;13(2):77-9.,

“Iodopropynyl Butylcarbamate,” English Articles, June 9, 2010,

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  1. Chrissy D. says

    Free and Clear is an excellent brand that my allergist recommended. I have this allergy as well as fragrance allergy, so talk about eliminating everything! You can buy products at Walgreens or on Amazon.

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