IGS Position Statement on Methylisothiazolinone and Methylchloroisothiazolinone (MIT/MCIT)

International Grooming Society — IGS

Global Groomer Health Initiative — GGHI

Note

The full Comprehensive Report on Methylisothiazolinone and Methylchloroisothiazolinone (MIT/MCIT): Health, Occupational, Manufacturing and Environmental Effects, developed by the International Grooming Society, is available exclusively to IGS members.

This in-depth report provides a detailed analysis of MIT/MCIT in relation to skin health, occupational exposure, animal grooming products, environmental impact, manufacturing impact and the IGS Ingredient Classification Framework.

IGS members can access the full report here: https://www.internationalgroomingsociety.org/post/comprehensive-report-on-methylisothiazolinone-and-methylchloroisothiazolinone-mit-mcit-health-oc

Not an IGS member yet?Join IGS to access the full report and other professional resources developed through the Global Groomer Health Initiative (GGHI).

1. Introduction

The International Grooming Society (IGS) promotes an evidence-based, welfare-oriented and globally responsible approach to animal grooming.

Through the Global Groomer Health Initiative (GGHI), IGS works to improve professional awareness around the real conditions of grooming work, including repeated exposure to water, surfactants, preservatives, disinfectants, cleaning products, aerosols and other substances used in daily practice.

As part of this mission, IGS evaluates commonly used ingredients not only from the perspective of product performance, but also through the lenses of:

• skin health and barrier respect

• occupational exposure

• animal exposure

• environmental impact

• manufacturing impact

• long-term sustainability

• professional prevention

Methylisothiazolinone and methylchloroisothiazolinone, commonly referred to as MIT/MCIT, MI/MCI, MCI/MI, CMIT/MIT or historically Kathon CG, are synthetic preservatives belonging to the isothiazolinone family.

They are used for their antimicrobial activity in water-based products, including cosmetics, shampoos, conditioners, cleaning products, detergents and some animal grooming products.

2. Why MIT/MCIT Matters in Grooming

MIT/MCIT is not simply a technical preservative system. It is a biologically active preservative combination designed to prevent microbial growth.

In grooming, this matters because professionals may be exposed to preserved products repeatedly throughout the working day. A product may be considered acceptable under occasional consumer-use conditions, but professional grooming involves a different exposure reality:

• repeated hand contact

• wet work

• cumulative skin barrier stress

• contact with shampoos, conditioners and sprays

• exposure to cleaning products and detergents

• possible exposure through multiple products containing related preservatives

For this reason, IGS believes that MIT/MCIT must be evaluated through a professional and preventive lens, not only through general cosmetic-use assumptions.

3. IGS Scientific Position on Skin Health

IGS recognizes that MIT/MCIT is strongly associated in dermatological literature with:

• skin sensitisation

• allergic contact dermatitis

• irritation concerns

• reactions in already sensitised individuals

The MIT/MCIT combination is of particular concern because it combines two sensitising isothiazolinones. Methylchloroisothiazolinone is generally considered the more potent sensitiser, while methylisothiazolinone is also well documented as a contact allergen.

From a skin health perspective, IGS considers MIT/MCIT to be incompatible with advanced skin-respecting grooming practices, especially when used in products intended for frequent professional use.

4. Occupational Health Perspective

Groomers represent a specific exposure group. They are not exposed like ordinary consumers.

Professional grooming often involves:

• repeated product handling

• frequent washing

• long periods of wet work

• contact with surfactants and preservatives

• cumulative irritation

• increased risk of occupational dermatitis

Even when a product is rinsed off the animal, the groomer may still handle similar preserved products many times during the day.

IGS Position — Occupational Health:MIT/MCIT-containing products may contribute to occupational skin risk, especially in repeated-use professional contexts. Their use should be avoided whenever possible in grooming products intended for frequent salon use.

5. Animal Grooming Product Relevance

IGS is particularly concerned that animal grooming products may not always be regulated, labelled or evaluated in the same way as human cosmetics, depending on the jurisdiction.

This creates a potential gap in professional awareness and consumer protection.

Products of particular concern include:

• shampoos

• conditioners

• coat sprays

• detangling sprays

• deodorising sprays

• leave-on products

• products used on sensitive or compromised animals

MIT/MCIT may expose not only the animal, but also the professional groomer and the owner who later comes into contact with the groomed animal.

6. Environmental Position

MIT/MCIT also raises environmental concerns because it is a synthetic biocidal preservative system.

Its function is to inhibit microbial growth. This biological activity may be useful inside a product, but it must also be considered when evaluating environmental release.

IGS recognizes that the environmental risk depends on concentration, use pattern, wastewater treatment and discharge conditions. However, MIT/MCIT has a concerning aquatic toxicity profile and is not aligned with a low-impact or regenerative approach to grooming.

IGS Position — Environment:MIT/MCIT cannot be considered environmentally neutral. Its aquatic toxicity profile and synthetic biocidal function make it poorly aligned with environmentally responsible grooming practices.

7. Manufacturing Impact

The IGS Ingredient Classification Framework includes manufacturing impact as a key evaluation axis.

MIT/MCIT is not a natural or minimally processed ingredient. It is a synthetic industrial biocidal preservative system used not only in cosmetics, but also in broader industrial sectors.

From an IGS perspective, this matters because ingredient evaluation must include not only the finished product, but also:

• chemical transformation

• industrial function

• production context

• biological reactivity

• environmental release

• long-term sustainability

IGS Position — Manufacturing Impact:MIT/MCIT has a high manufacturing-impact concern because it belongs to a synthetic industrial biocide category and is designed for antimicrobial activity.

8. IGS Ingredient Classification

Framework

Within the IGS Ingredient Classification Framework, MIT/MCIT is classified as:

Category D — Non-Compatible / High Concern Preservative

Classification rationale

MIT/MCIT is classified as Category D because:

• it combines two sensitising isothiazolinones

• it is strongly associated with allergic contact dermatitis

• it has occupational relevance for wet-work professions

• it may be present in grooming products

• it raises concerns for animals, groomers and owners

• it has a concerning aquatic toxicity profile

• it is a synthetic industrial biocidal system

• it is not aligned with advanced skin-respecting and environmentally responsible grooming practices

9. IGS Final Position

The International Grooming Society considers MIT/MCIT to be a high-concern preservative system in grooming products.

Although preservation is necessary in many water-based formulations, not all preservation systems are equally aligned with skin health, occupational safety and environmental responsibility.

IGS does not present this position as a rejection of preservation itself. Instead, this position supports a more responsible transition toward safer and lower-impact formulation choices.

IGS Position Summary

MIT/MCIT should be avoided in grooming products whenever possible and replaced by lower-risk preservation strategies aligned with skin health, occupational safety, animal welfare and environmental responsibility.

10. Closing Statement

The purpose of this position statement is not to create fear, but to support professional prevention.

Through the Global Groomer Health Initiative, IGS aims to help groomers better understand what they work with every day and how ingredient choices may affect:

• their own health

• the animals in their care

• their working environment

• the wider ecosystem

Professional grooming deserves more than marketing claims. It deserves transparent information, evidence-based education and practical tools for safer decision-making.

Access the Full Report

The complete IGS report on MIT/MCIT is available exclusively to IGS members.

Access the report here:

https://www.internationalgroomingsociety.org/post/comprehensive-report-on-methylisothiazolinone-and-methylchloroisothiazolinone-mit-mcit-health-oc

Not a member yet?

Join the International Grooming Society to access this full report and other GGHI resources designed to support safer, healthier and more responsible grooming practices.