Veterinarian Reviewed on June 20, 2012 by Paulina Nelega, RH
Posted in Uncategorized



Methylchloroisothiazolinone is considered to be a preservative that has amazing antibacterial and antifungal properties. It has been proven to be effective in destroying gram positive and gram negative bacteria types. It is also able to kill yeast and fungi.
Methylchloroisothiazolinone is found in many water based skin care products. This chemical is also used in the cosmetic industry as well. It may also be used in combination with other preservatives such as ethylparaben and benzalkonium chloride.
Although this chemical is used as a preservative, there have been many accounts of skin allergic reactions due to the use of methylchloroisothiazolinone.

History and Origin

Methylchloroisothiazolinone was first used in the cosmetics industry during the 1970’s and afterwards it was used further as a preservative in a variety of products like glue, paints, fuels, soaps, chemical cleaners and detergents. The Cosmetic Ingredient Review (CIR) has determined that methylchloroisothiazolinone is safe to use as an ingredient for cosmetics provided it adheres to certain concentrations and limitations. It is generally considered to be safe to use although it does contain certain types of qualifications.

Ancient Uses

The use of methylchloroisothiazolinone during ancient times was unheard of. Cosmetics were first used by tribes when hunting and in important tribal festivities. Skin care on the other hand, just involved using extracts of herbs and fruits; these were also used in treating minor skin care conditions as well.

Modern Uses

During modern times, methylchloroisothiazolinone was used mainly as a preservative in skin care products and hair care products. It is found in personal care products that were used as a rinse-off product. This chemical was later stabilized after other forms of preservatives were added.

Methylchloroisothiazolinone is also an active ingredient in shampoos, conditioners, hand soaps, hand wipes and industrial strength cleaners. The use of this chemical in cosmetics was reviewed by the Cosmetic Ingredient Review (CIR) saying that methylchloroisothiazolinone must be regulated and must be used under some qualifications. It was however found to be safe when used under special regulations.

Side Effects

Methylchloroisothiazolinone in high concentrations can cause chemical burns and can irritate the skin and nearby membranes. Because of this property, it was removed from many cosmetic and personal skin care products; only rinse off types of methylchloroisothiazolinone were allowed to be used.

It is highly suggested that products with methylchloroisothiazolinone must not be used by people with sensitive skin. Babies and very young children are contraindicated to use products with this chemical. Although is found to be safe under some qualifications by the Cosmetic Ingredient Review (CIR, women must still be keen in using cosmetics and skin care products that contain methylchloroisothiazolinone. If you must wear makeup which contains this chemical as a preservative, remove makeup as soon as you can. After removal, wash face thoroughly with a mild soap and warm water to remove every trace of makeup on your face. Never allow the day pass without removing all traces of makeup.
If you experience any skin irritation and burning sensation on your skin after using products with methylchloroisothiazolinone, discontinue product, rinse all traces of the product on your face and consult a medical professional immediately.

Read also: Saw Palmetto

Our Expert

Paulina Nelega, RH
Paulina Nelega, RH, has been in private practice as a Clinical Herbalist for over 15 years. She has developed and taught courses in herbal medicine, and her articles on health have appeared in numerous publications. She is very passionate about the healing power of nature. Ask Dr. Jan

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