What do the Clean, Low, Watch and Swap levels mean?

They are cut from a continuous concern level the app computes from the sourced claims that the chosen evidence lens shows: each claim counts its concern class, tier weight, confidence and dose relevance, combined worst-first with a decay so one serious finding outweighs many small ones, then scaled by how much of the substance reaches you in this use. Clean is below 0.35, Low below 1.1, Watch below 2.0 and Swap above that, on a 0 to 3 scale.

Is Methylchloroisothiazolinone safe on skin (rinsed off)?

Q: Is methylchloroisothiazolinone safe on skin (rinsed off)?

Under the app's default Cautious lens, methylchloroisothiazolinone on skin (rinsed off) rates Watch: worth watching; the app would list a cleaner alternative type. 4 sourced concerns count (irritant · allergen, consensus tier; environmental, consensus tier; suspected carcinogen, emerging tier). This is research with sources, not medical advice.

Personal care1 use researched4 sourced claims

Where it turns up: preservative in rinse-off products. Detox My Life researched methylchloroisothiazolinone under one use, because the same substance means something different in each use. Every claim below carries its evidence tier, how sure the research is that it applies here, and the sources it cites. The level is computed by the app's own deterministic engine, so the page says exactly what the app would.

Level by use and lens

Use	Mainstream	Cautious (default)	Based	Concerns · favour · fringe
On skin, rinsed off	Watch	Watch	Watch	4 · 0

Mainstream shows consensus claims only; Cautious adds emerging research; Based adds fringe claims, labelled as such. The last column counts, under Cautious, the sourced concerns, the findings in its favour and the fringe claims Based would add.

Safer swaps: the app's swap catalog has no entry tied to this ingredient yet. When you scan a product that contains it, the app suggests cleaner alternative types for that product; the swap categories list what the catalog covers today.

On skin, rinsed off Watch

Under the default Cautious lens methylchloroisothiazolinone on skin (rinsed off) rates Watch: worth watching; the app would list a cleaner alternative type. Mainstream (consensus only) rates it Watch; Based (adds the fringe) rates it Watch. Researched 2026-09-03.

Sourced concerns (4)

ConsensusIrritant · allergenconfidence 100%

Methylchloroisothiazolinone (MCI), often combined with methylisothiazolinone (MI), is a potent skin sensitizer that can cause allergic contact dermatitis in individuals, even at concentrations permitted in rinse-off products.

Why here: Repeated daily application of rinse-off products containing MCI/MI, especially those with detergents, can enhance skin penetration and accumulation, leading to sensitization and elicitation of allergic reactions.
What would have to be true: Allergic reactions have been observed in sensitized individuals exposed to rinse-off products containing 50 ppm or more of MI (often combined with MCI). Regulatory limits in the EU for MCI/MI in rinse-off products are 0.0015% (15 ppm).

Sources the engine cites:

Methylisothiazolinone in rinse-off products causes allergic contact dermatitis: a repeated open-application study — nih.gov (2015) · regulator or public body
Methylisothiazolinone contact allergy - are rinse-off cosmetics and household products relevant sources of exposure? — nih.gov (2016) · regulator or public body
4 web articles (healthline.com, betterscalpcompany.com, carinawoodruff.com, …), linked in the app.
2 community or commercial pages, not counted here.

ConsensusEnvironmentalconfidence 100%

Methylchloroisothiazolinone (MCI) is classified as very toxic to aquatic life with long-lasting effects.

Why here: Rinse-off products containing MCI are washed down drains, leading to their release into wastewater systems and potential exposure to aquatic environments.
What would have to be true: The environmental hazard is primarily associated with the concentrated raw material, but the presence in finished rinse-off products contributes to its release into the environment.

Sources the engine cites (no regulator, review or study among them):

1 community or commercial page, not counted here.

EmergingSuspected carcinogenconfidence 80%

Isothiazolinone preservatives, including methylchloroisothiazolinone (MCI), have been suggested to be potentially linked to carcinogenicity.

Why here: While direct dermal rinse-off exposure leading to carcinogenicity is not definitively established, the presence of the substance in products used on the skin means some level of systemic absorption could theoretically occur.
What would have to be true: These claims are based on broader assessments of isothiazolinones and require more research to establish direct links to dermal rinse-off exposure.
The other side: The International Agency for Research on Cancer (IARC) does not list methylchloroisothiazolinone as a known, probable, or possible human carcinogen. More research is necessary to support claims of carcinogenicity.

Sources the engine cites (no regulator, review or study among them):

1 web article (healthline.com), linked in the app.
1 community or commercial page, not counted here.

EmergingEndocrineconfidence 80%

Methylisothiazolinone (MI), often found with methylchloroisothiazolinone (MCI), was placed on the TEDX List of Potential Endocrine Disruptors, and isothiazolinone preservatives are associated with endocrine disruption in humans and aquatic animals.

Why here: While direct dermal rinse-off exposure leading to endocrine disruption is not definitively established, the presence of the substance in products used on the skin means some level of systemic absorption could theoretically occur.
What would have to be true: These claims are based on broader assessments of isothiazolinones and require more research to establish direct links to dermal rinse-off exposure.
The other side: More research is necessary to support claims of endocrine disruption from dermal rinse-off exposure.

Sources the engine cites (no regulator, review or study among them):

1 community or commercial page, not counted here.

Not researched here

The engine has no dossier for methylchloroisothiazolinone when cooked with heat, in cold food, as a finishing ingredient, in heated food packaging or other uses. The app researches an ingredient for the use it infers from your product, so a scan fills these in; this page only shows what has already been researched and source-verified.

This is research, not medical advice. Detox My Life shows sourced claims sorted by evidence tier. It does not diagnose, treat, or tell you to start or stop anything. Talk to a qualified professional about your health.

Scan your own. The app reads any product label with your camera, works out how you are about to use it, and researches every ingredient for that use with live sources. Every scan adds to a Detox Score for your home, where 50 is a typical home in your region, and a plan of next swaps.

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