What is DMDM?

DMDM-Hydantoin is defined as a formaldehyde-releasing agent and is primarily used as a preservative in cosmetic and personal care products.

It is the ingredient identified in over a dozen hair care lawsuits as being responsible for extreme hair loss and scalp irritation. You can read more about those law suits in THIS post.

What that means is that DMDM slowly reacts with water and creates Formaldehyde, which is widely accepted as one of the most toxic chemicals out there.

Formaldehyde is classified as a Group 1 carcinogen by the International Agency for Research on Cancer, meaning it is known to cause cancer in humans (1) including multiple myeloma, non-Hodgkin’s lymphoma, ocular melanoma, leukaemic, cancer of the respiratory tract, brain, connective tissue, pancreas, lymphoid, and colon. (2)

Other health concerns include irritation of the eye and respiratory tract, pulmonary disease including bronchial asthma and e histopathological lesions in the nose, localized allergic reactions, contact dermatitis and has been implicated as the responsible agent in the development of neurobehavioural disorders such as insomnia, lack of concentration, memory loss, and mood and balance alteration. (2)

There is also increasing evidence of genetic effects not to mention is aquatic toxicity, especially on marine algae.

Bottom line is that it’s harmful, but the good news is that there are an abundance of safer options that companies could (and should) be using.

Occupational health and safety authorities throughout the world are now more strictly regulating the use of formaldehyde due to growing concerns about its effects on human health and our environment.

In fact, it’s presence is banned in cosmetic and personal care products in Sweden and Japan and restricted in Europe and Canada, yet there is no current US regulation that bans or restricts its use in our products (except via Prop 65 in California).

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The problem is that you will never see Formaldehyde listed as an ingredient in the products you use in your home.

That is because there are ingredients out there that actually chemically decompose into formaldehyde in the presence of water. That means that companies can add them to a product, any product, that contains water, and it will be just like you a preserving it with formaldehyde, without having to say that they are using this highly toxic chemical.

DMDM Hydantoin is one of these ingredients.

It’s ability to slowly release formaldehyde into products accomplishes two goals for the companies that use them:

  1. Formaldehyde can be used as the preservative in their products without having to be listed as an ingredient on the label
  2. The amount of Formaldehyde present in the product increases the longer it sits on the shelf or in your home

While there are dozens of other preservatives out there, many of which are knows to be safe, some companies (usually the big guys) choose not to use them because they are more expensive.

It is cheaper for them use an ingredient that is a known human allergen and potential immunotoxin and settle a potential future lawsuit with you than to use a preservative that is just a it more expensive and proven safe.

In fact, according to data from the federal Food and Drug Administration, nearly 1 in 5 cosmetic products contains a substance that generates formaldehyde, a known human carcinogen. (3)

If you are ready to get started remove formaldehyde, and ingredients that hide it, from the products in your home be sure to avoid the following list of ingredients (4):
Dimethyl-dimethyl (DMDM) hydantoin
Imidazolidinyl urea
Diazolidinyl urea
Polyoxymethylene urea
Sodium hydroxymethylglycinate,
2-bromo-2-nitropropane-1,3-diol (bromopol)

Also be sure to choose nail products that are labeled formaldehyde-free or “toxic-trio-free” (formaldehyde, toluene and DBP) and skip hair-smoothing products—especially those sold in salons, as salon-based products are exempt from labeling laws.

Should you choose to dispose of products that you have in your home that contain DMDM or any other ingredients you have grown uncomfortable with using, the best way to do so is to wear a mask (much of the concern with DMDM Hydantoin comes from inhalation), dump the contents in the trash can and then rinse and recycle the bottle.

I’ve been on the journey to finding safe products from brands that are truly making a difference for over a decade. You can trust that the ones I’ve chosen to highlight and support inside of my Product Finder will never contain DMDM or any other petrochemicals that I no longer use in my home.

1) Agents Classified by the IARC Monographs, Volumes 1–129 – IARC Monographs on the Identification of Carcinogenic Hazards to Humans. (2021, June 20). International Agency for Research on Cancer. https://monographs.iarc.who.int/agents-classified-by-the-iarc/
2) Liteplo, R. G., Beauchamp, R., Meek, M. E., & Chénier, R. (2002). Concise International Chemical Assessment Document 40: Formaldehyde. World Health Organization Geneva. https://www.who.int/ipcs/publications/cicad/en/cicad40.pdf
3) Exposing the Cosmetics Cover-up. (2013, October 10). Environmental Working Group. https://www.ewg.org/research/exposing-cosmetics-cover
4) Formaldehyde And Formaldehyde-Releasing Preservatives. (2021). Safe Cosmetics. https://www.safecosmetics.org/get-the-facts/chemicals-of-concern/formaldehyde/


  1. Alisha says:

    I have been using Nexxus Ultimate Moisture Shampoo for about 2 years now and loved what it did to my hair. 6 months ago I started having hair loss issues, nothing too excessive but enough for my hair stylist to notice, especially in my front hair line. We chalked it up to stress and poor eating habits. In the past few months I’ve noticed that my scalp is consistently itchy. I started thinking maybe my issue was more neurological since I have other nervous system issues. I am so grateful for this article, because I feel that you have given me the real answer I have been searching for. I will definitely be doing some research on the Shampoo to replace it because I am never putting that product in my hair again!

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