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Today's Chemical:


EWG Risk Score:


What is it?

Methylisothiazolinone  is a synthetic cosmetic preservative.

Why is it a risk?

  • Methylisothiazolinone is a known neurotoxin.  In 2004, the European Scientific Committee on Cosmetic Products and Non-Food Products Intended for Consumers (SCCNFP) suggested that companies limit the maximum concentration to 0.01% (100 ppm).  However, US companies are not required to follow this guideline.
  • It is known to be absorbed through skin.  A study at the Pittsburgh School of Medicine concluded that "Prolonged exposure to low levels of MIT and related compounds may have damaging consequences to the developing nervous system." 
  • Is a developmental toxin.  (Source
  • Is a known contact allergen.  (Source)

Steph's Opinion:

Although concentrations of this ingredient are typically very low in a formulation, I personally suggest avoiding this ingredient. 

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Reader Comments (45)

Donna Robbins, I'm curious about how you are doing after reacting to an allergy to MI in Behr Paint. My daughter seems to be having a similar reaction, we just painted her room about 6 months ago and she has been having horrible facial rashes, ear rashes, excema flare ups. She had patch testing done in June and tested postive to MI. We've painted other rooms in our house but haven't used Behr brand, we've used Bejamin Moore. Thanks.

Thu, October 29, 2015 | Unregistered CommenterJen Smith

Has anyone tried to make any products successfully on their own? I have seen on other sites that people have tried to make their own hand soap and detergent.
Also, wondering if anyone know specific make up brands that are free of MIT?
Everything time I think I have gotten all of the allergy culprits another one pops up.

Sun, November 29, 2015 | Unregistered CommenterFayth C.

Methylisothiazolinone has just received its SCCS EU European Union Final Opinion on Methylisothiazolinone. You may wish to search and find the new Opinion by the SCCS even if it is not directly pertaining to US standards YET, and post link as it becomes open publish. Basically, we lose. Mostly. They will allow MI (Europe abbrev) or MIT (US abbrev) in Rinse -Off cosmetics ( washes/hair shampoos and rinse off conditioners/ bodywashes ) at 15 part per million (ppm), so it will be required to be dramatically reduced from the 100 ppm previously said to be" SAFE". So for those already allergic through sensitization from previous contact and exposure with products, we are all out of luck -even in Europe where the chemical is actually being regulated. (NOTE: once the allergen MIT has made itself known to your immune system through its strong sensitizing capabilities, permanent allergy remains. 15 ppm will not help. The cell mediated type lV immune mediated allergy sufferers may be reacting to levels as low as under 1-3 ppm, aggregate exposure in all public places has not yet been studied for the Isothiazolinones , which are a large a group of related allergen compounds, so its possible that one will be in constant exposure through large scale ventilation systems as its used as a biocidal in air cooling systems etc..
NO SAFE LEVEL has yet been determined for those already sensitized and no safe level or ppm to MIT exposure, that will not elicit reactions exists .
the SCCS has determined that MIT is NOT safe for the consumer at current use levels as a sensitizer, The US is Not currently using SAFE levels. period.
You can make careful cosmetics decisions and you should. But as for cleaning products: Use caution and my reminder: dish soap gets on and sits on skin. multiple times per day. There are almost no MIT free safe dishsoaps in the US currently. I suggest wearing dish washing gloves at all times unless using something utterly free from any skin sensitizers such as a castile liquid soap. Or make your own- which is just crazy time consuming and most will not do.

Heres some options. Dr Bronners castile soap, or a bar soap, or a Soapnut based dishliquid that does not contain MIT (FIT Organics) Planet brand also makes one but it has SLS. although I have been using it when in a pinch. I can not even have MIT in my home on any level, in anything. You should see the photodocumentation pictures of my hands. patch test positive identification of Methylisothiazolinone allergy through contact allergist found the cause , But even then the damage was so extensive that it took nearly a full year of recovery with medical gauze wraps, thousands of dollars and countless medical specialist visits to "fix" my hands... go add that SCCS final Opinion, and watch for what is NOT happening in the US. ( FDA EPA sitting on hands) CIR leading the way for "wait and do nothing " and hope no one noticed. oops.

Fri, January 29, 2016 | Unregistered CommenterRebekah Baharestan

I have become permanently sensitized to methylisothiozolinone which caused severe itchy rash with blisters. It is no longer safe for me to shake hands with anyone or touch anything that has come in contact with it.

Sun, February 21, 2016 | Unregistered CommenterMichelle

I have this chemical sensitivity. This chemical is in most sunscreens. Elta Sport, while expensive, does not have it but it's only available at the dermatologist. I cannot use Pantene hair products and cannot color my hair. I've found that Cetaphil baby body wash and shampoo does not contain it and my scalp no longer itches. I also think my hair shedding has stopped. I have to wash my hair before going for a haircut. All Free and Clear laundry detergent and fabric softener are also good. I didn't know about Dawn dishwashing liquid so I guess I'll be searching for something else to use. Good info on this blog.

Wed, March 2, 2016 | Unregistered CommenterAnn

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