Chemical of the month: Iodopropynyl butylcarbamate (IPBC)

By toxicologist Ewa Daniél

What is it?

Iodopropynyl butylcarbamate or IPBC is a preservative used in wet wipes, paint, primers, coating and cosmetics to prevent bacteria and fungi’s in the products. It has been approved by the FDA for use as a component of adhesive that may safely be used in articles intended for use in packing and holding food. IPBC was developed in the 1970´s for industrial use in the wood industry as a preservative for paint and coating and in 1996 it was approved for cosmetics. In the EU, IPBC is not allowed in leave on products to small children (≤3 years).

The use of IPBC in cosmetics in the European Union is subject to the restrictions described in Annex VI, Part I of the Cosmetics Directive. Because of the iodine content the concentration allowed to use in cosmetic products is regulated to:

  • Rinse off 0,02 %
  • Leave on 0,01 %
  • Deodorants/antiperspirants 0,0075 %

So, what is the problem?

IPBC was for a long time considered to have a low allergenic potential. However because of the extended use in many products and the fact that it is a small molecule that can penetrate the skin, it can cause contact dermatitis in especially leave on products from specific product groups. Because of the wide use of IPBC a big populations study was done in Denmark from 2000-2011, where all patients who had a patch test were included in the study.

9755 patients were tested and 54 cases of allergy to IPBC was found.

Allergy to IPBC was significant more prevalent among men and patients with occupational dermatitis. The study concluded that IPBC continues to be among the less frequent allergens, and furthermore that IPBC allergy is typically related to men over 40 years old working in the wood industry and with hand eczema.

To conclude: In Denmark – and we believe this may be extrapolated to the rest of the EU – IPBC allergy is related to the male sex, age > 40 years, hand eczema, and occupational exposure. Physicians should be encouraged to investigate possible occupational exposure if IPBC sensitization is detected.  

What the experts say about IPBC

The safety of IPBC has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel twice. The first assessment was made in 1998 where the CIR Expert Panel concluded that IPBC was safe as cosmetic ingredient at concentrations ≤0,1 %, but it should not be used in aerosol products, because of a negative effect in lungs.

In 2016 new studies were made and a re-assessment on IPBC was made. CIR evaluated the updated scientific data and according to the panel there is a low degree of sensitization observed in some studies and mild dermal irritation potential of IPBC at concentrations of 0.5% and above. IPBC was negative in tests for mutagenicity, carcinogenicity and reproductive and developmental toxicity. The CIR concluded that IPBC was safe as a cosmetic ingredient at concentrations less than or equal to 0.1%, but IPBC should not be used in products intended to be aerosolized.

The Scientific Committee on cosmetic product intended for consumers (SCCNFP) is of the opinion that IPBC is safe for use in cosmetic products as a preservative at a maximum concentration of 0,05 %. The SCCNFP proposes the following further restriction or condition for its use in cosmetic products: the substance should not be used in oral hygiene and lip products. Leave on products containing more than 0,02 % IPBC must be labelled “contain iodine”.  


AllergyCertified make an allergy risk assessment for all ingredients used in a certified product. The assessment of IPBC shows that IPBC can be allowed in mascara since both the exposure and the concentrations (≤ 0,01 %) used in mascara is so low that it is safe to useBut in other products with a bigger exposure than mascara this preservative is not allowed because of the risk of getting an allergic reaction.  


  • Alejandro Martin-Gorgojo and Jeanne Duus Johansen Contact dermatitis caused by Iodopropynyl butylcarbamate in Denmark Contact dermatitis 69, 78-85; 2013  
  • Final report on the safety assessment of iodopropyl butylcarbamate (IPBC) International Journal of Toxicology, 17(SuppL 5):1-87, 1998  
  • Re-review Safety Assessment of Iodopropynyl Butylcarbamate as Used in Cosmetics September 9-10, 2013  
  • AllergyCertified advisoryboard meeting about IPBC october 2017