Fragrance avoidance
No fragrance-linked caution surfaced in the current profile.
This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.
- beauty
2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol
CAS 1444596-49-9 · 70/100 · High conf.
Concern score
70/100High concern based on regulatory listings.
High confidence
2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol in plain language
On cosmetic ingredient lists it appears as “Hc red no. 18”.
Also known as Hc red no. 18 · HC Red No 18
Used in cosmetics as a hair dye.
- Hair dyeing
- High concern: no hazard classifications on record. It is restricted in EU cosmetics.
Why it's flagged
2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol is restricted in cosmetic products under Annex III of the EU Cosmetics Regulation (EC) 1223/2009.
RestrictedEU EC — restricted
The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.
Regulation
Restrictions first, then routine listings from published regulatory sources.
- EU Annex III — restricted
- EU restricted in cosmetics
- View source →restricted
EUEC
Annex III of EU Cosmetics Regulation (EC) 1223/2009: substances which cosmetic products must not contain except subject to the restrictions laid down. Product types: (a) Hair dye substance in oxidative hair dye products (b) Hair dye substance in non-oxidative hair dye products Maximum concentration: (b) 0,5 % Other conditions: For (a): After mixing under oxidative conditions the maximum concentration applied to hair must not exceed 1,5 %. Conditions of use and warnings: For (a): To be printed on the label: The mixing ratio. “Hair colourants can cause severe allergic reactions. Read and follow instructions. This product is not intended for use on persons under the age of 16. Temporary ‘black henna’ tattoos may increase your risk of allergy. Do not colour your hair if: — you have a rash on your face or sensitive, irritated and damaged scalp, — you have…
Expert safety opinions
No expert opinion on file for 2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol. These are the independent scientific bodies that assess ingredients like this one; we show an opinion only when a record we hold cites it.
SCCS
EU Scientific Committee on Consumer Safety
No SCCS opinion on file.
CIR
Cosmetic Ingredient Review (US expert panel)
No CIR safety assessment on file.
Evidence & sources
No graded research studies for 2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.
Suitability
Context-specific fit derived from published classifications and the current ingredient evidence profile.
Good fit