Formaldehyde-releasing preservatives in cosmetics

What are formaldehyde-releasers?
Formaldehyde-releasing preservatives are actively used in personal care products since they effectively prevent growth of bacteria and fungi  1, 2. As the name implies, over time these chemicals slowly decompose and produce formaldehyde.
The most common formaldehyde-releasers are 3:
1) Diazolidinyl urea
2) Imidazolidinyl urea
3) DMDM hydantoin
4) 2-bromo-2-nitropropane-1,3-diol (bromopol)
5) Sodium hydroxymethylglycinate
6) Methenamine 3-chloroallylochloride (Quaternium-15)

Where are these preservatives used?
Formaldehyde and formaldehyde-releasers are widely used in the following products 4:
1) Hair products (shampoos and conditioners)
2) Moisturizers (cream and lotions)
3) Nail products (hail hardeners, nail polish)
4) Shaving products
5) Oral care products (tooth paste, mouth wash)
6) Deodorants

Formaldehyde in nature and our body
Formaldehyde is a colorless gas with an irritating odor. It occurs naturally in nature through a variety of biological and chemical processes, but it is quickly decomposed by sunlight and bacteria 5. Formaldehyde is also naturally present in the human body at very low concentrations 5, however, it is quickly converted to formic acid and excreted via the kidneys 6.

Formaldehyde in cosmetics
Different formaldehyde-releasers produce different amount of formaldehyde. Thus, quaternium-15 releases the largest amounts of formaldehyde, followed by diazolidinyl urea, DMDM hydantoin, and imidazolidinyl urea 3. Other cosmetic ingredients might also contain trace amounts of formaldehyde – in case it was used for the synthesis or preservation of raw materials. Degradation of some compounds in cosmetic products (e.g. polyethyleneglycol ethers) also brings an additional amount of formaldehyde 7. The amount of released formaldehyde also depends on the composition of the cosmetic product and its storage conditions. The older the product, the more formaldehyde is produced. In addition, the raise of temperature also increases formaldehyde production 3.

Are formaldehyde-releasers dangerous?
The main concern about these preservatives is that they release formaldehyde - a toxic, carcinogenic and sensitizing chemical 6.
1. Cancer
Multiple animal studies have demonstrated that formaldehyde causes respiratory tract tumors 8. Later it was confirmed that formaldehyde exposure is also associated with nasopharyngeal and sinonasal cancers in humans 9.
2. Sensitization
Contact allergy to formaldehyde is quite common: about 8-9% of US consumers and 2-3% of EU consumers are sensitive to this chemical 10. Thus, formaldehyde-releasing preservatives can also cause allergic contact dermatitis in sensitive persons 3. On the other hand, allergy to formaldehyde does not necessarily mean allergy to one or more formaldehyde-releasers 3. Nevertheless, doctors recommend patients allergic to formaldehyde to avoid leave-on cosmetics preserved with formaldehyde-releasers 3.

Regulations concerning formaldehyde and formaldehyde-releasers
According to the EU regulation on cosmetic products, formaldehyde can be used at a concentration of up to 5% in nail hardening products labeled as ”contains formaldehyde” 11. Other formaldehyde-releasers can be used at concentrations between 0.2-0.6%.

Exposure to formaldehyde in real life is incomparably less than in experimental studies demonstrating carcinogenic potential of this chemical. Thus, formaldehyde-releasers do not pose any risk to the consumer unless their concentration in final product is exceeded 1. However, personal care products containing these preservatives may cause allergic contact dermatitis in sensitive persons 3.
Thus, if you have cosmetics with formaldehyde-releasers we recommend the following:
1) Throw away old cosmetics (upon storage increased levels of formaldehyde will be released) 3.
2) Do not keep your cosmetics in the bathroom since the amount of released formaldehyde increases with temperature 12.
3) If you ever had cosmetics-related allergies, test the product with formaldehyde-releasers before using it: apply some of the product on the skin at the bend of elbow and leave for 24-48 hours. Avoid getting the test-area wet while taking shower. If during this time any irritation occurs, do not use the product. To be on the safe side, avoid cosmetics containing formaldehyde-releasers.

This article is based on reviewing multiple studies published in peer-reviewed scientific journals and safety reports of European commission and U.S. Department of Health and Human Services.


What is your opinion about formaldehyde-releasers? Let's talk about it together!



  1. Scientific Committee on Cosmetic Products and Non-food Products intended for consumers (SCCPNP) (2002). A clarification on the formaldehyde and para-formaldehyde. Entry in Directive 76/768/EEC on cosmetic products. 22nd plenary meeting of 17 December 2002. Available here
  2. de Groot AC, Veenstra M. (2010) Formaldehyde-releasers in cosmetics in the USA and in Europe. Contact Dermatitis. 2010 Apr;62(4):221-4. doi: 10.1111/j.1600-0536.2009.01623.x. Epub 2010 Mar 3.
  3. de Groot A, White IR, Flyvholm MA, Lensen G, Coenraads PJ. (2010). Formaldehyde-releasers in cosmetics: relationship to formaldehyde contact allergy. Part 2. Patch test relationship to formaldehyde contact allergy, experimental provocation tests, amount of formaldehyde released, and assessment of risk to consumers allergic to formaldehyde. Contact Dermatitis. 2010 Jan;62(1):18-31. doi: 10.1111/j.1600-0536.2009.01631.x.
  4. Jackson EM. (2012) Formalehyde in personal care products. Skin Pharmacol Physiol. 2012;25(5):236-40. doi: 10.1159/000338429. Epub 2012 Jun 13.
  5. Priority Existing Chemical Assessment Report No. 28. National Industrial Chemicals Notification and Assessment Scheme Australia Formaldehyde 2006. Available here
  6. IARC (International Agency for Research on Cancer) (2006). Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol. IARC Monographs on the Evaluation of the Carcinogenic Risks to Humans Vol. 88. Lyon, France. Available here
  7. Dahlquist I, Fregert S, Gruvberger B. (1980) Detection of formaldehyde in corticoid creams. Contact Dermatitis 1980: 6: 494.
  8. Blair A, Saracci R, Stewart PA, Hayes RB, Shy C. (1990). Epidemiologic evidence on the relationship between formaldehyde exposure and cancer. Scand J Work Environ Health 1990;16:381–93.
  9. Review of the Formaldehyde Assessment in the National Toxicology Program 12th Report on Carcinogens (2014). Committee to Review the Formaldehyde Assessment in the National Toxicology Program 12th Report on Carcinogens; Board on Environmental Studies and Toxicology; Division on Earth and Life Sciences; National Research Council. Washington (DC): National Academies Press (US); 2014 Sep. Available here
  10. de Groot AC, Flyvholm MA, Lensen G, Menné T, Coenraads PJ. (2009) Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers. Contact Dermatitis. 2009 Aug;61(2):63-85. doi: 10.1111/j.1600-0536.2009.01582.x. Review.
  11. Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products (Text with EEA relevance). Available here
  12. Engelhardt H, Klinkner R. (1985) Determination of free formaldehyde in the presence of donators in cosmetics by HPLC and post-column derivation. Chromatographia 1985: 20: 559–565.



Sunny's picture

Just wondering, why in the US there are more people allergic to formaldehyde? Are people more sensitive? Or is it quality of cosmetics?

Natalia's picture

The reason of higher rates of allergies to formaldehyde-releasers in the US comes from differences in legislation. In the US allowed concentrations of these preservatives in cosmetic products are higher than in the EU, thus, in the US there are more cases of formaldehyde-related allergies.