USA: Free Shipping On Skin Care & Custom Orders
Cart 0

Harmful Chemicals To Avoid: MCI/ MI or Methyliosthiazolinone & Methylchloroisothiazolinone

Rolande Sumner Harmful Chemicals





One of the most common ingredients often found in cosmetics and household goods are Methylisothiazolinone and Methylchloroisothiazolinone (MCI/MI). According to Maria Antonieta Rios Scherrer and Vanessa Barreto Rocha, contributors to An Bras Dermatol, MCI/MI is a


“preservative mixture at a fixed combination (ratio 3/1), which is commonly used in cosmetic and industrial applications and can be found in cosmetics, especially shampoos, dermatological products, mainly sunscreens, household cleaning products, paints, moist toilet paper, metalworking fluids”

In their study they found that 60% of patients who came into contact with MCI/MI developed dermatitis and 82.5% developed lesions.

Will everyone develop lesions and dermatitis from contact with MCI/MI? No. Some users who come into contact with MCI/MI may never experience sensitivity. However, there are growing numbers of those in contact with MCI/MI who are experiencing sensitivity and allergic reactions. As a result, the FDA started conversations about Methylisothiazolinone and Methylchloroisothiazolinone in its public meeting November 30, 2011. (Food and Drug Administration, 2011) According to Dr. Phil Geis of Geis Microbiological Quality, MCI/MI is the most used and powerful preservative in the US and European Union. To make it easier for scientists to combine the preserve in products, it is mixed into a “cocktail” with other chemicals and preservative. Though Dr. Geis clearly states that MCI/MI is safe, he does admit

“When we apply too high a level or very high levels we can cause sensitization or reaction to the human skin. A lot of the industrial preservatives are not used in cosmetics because of this reason. The preservatives that are used in cosmetics are tested constantly for sensitization and most of the time when we have reports of sensitization they usually occur because people have higher levels than what are needed.” (Food and Drug Administration, 2011, page 90-91)

Dr. Geis then defends the use of preservatives, going as far to indicate that adding percentages of preservatives and alcohol on labels only stands to “demonize” the use of preservatives. He then states

“government is paid off by industry. The pharmaceutical industry spends a fortune in fees to the FDA to approve new drugs. They're called user fees. Congress mandates them. The law is up for review. Should we eliminate user fees for drugs? We approved -- the FDA approved more new drugs in 2011 than they did for the past two or three years combined. Why? Because they have user fees and have resources without having to raise taxes to pay for it.” (Food and Drug Administration, 2011, page 96)

In 2015 the FDA published their scientific studies which involved MCI/MI. (Food and Drug Administration, 2015), which speaks volumes.

As you transition from chemical based cosmetics and food, start to consider what is in your household goods. By no means do I suggest you do a clean sweep of every nook and cranny in your home right now. However, over time start to choose healthier cosmetics, food and household goods. You may find an improvement in your family, pets and your health.



Before I leave, I want to leave you with this thought. Not all preservatives are bad. Preservatives are used to keep cosmetics and the user safe. Imagine opening a bottle of your favorite cream just to discover that it’s green, fuzzy and smelly. Worse, imagine breaking out in a rash half way into using your body butter because it went bad. There are natural broad spectrum preservatives, antimicrobials and antioxidants which are safe for cosmetics use and far less harmful. Please don’t stop using skin care products because they contain a preservative. Instead ask your manufacturer about the products additives. For questions about Butter Angels skin care products, please review the Ingredients page on the main site or email us at

Below is a video post on YouTube by J. Kraken addressing MCI/MI. 



Food and Drug Administration. (2011). Public Meeting: Cosmetic Microbiological Safety Issues. Public Meeting: Cosmetic Microbiological Safety Issues. Retrieved from

Food and Drug Administration. (2015, June 25). Determination of methylisothiazolinone and methylchloroisothiazolinone in cosmetic products by ultra high performance liquid chromatography with tandem mass spectrometry. Retrieved from

Kraken, J. (Director). (April 28, 2015). Isothiazolinone, Methylisothiazolinone and Chloroisothiazolinone Allergy [Motion Picture]. Retrieved from

 Scherrer, M. A. R., & Rocha, V. B. (2014). Increasing trend of sensitization to Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) . Anais Brasileiros de Dermatologia, 89(3), 527.




Older Post Newer Post

Leave a comment