What does 4-NITROGUAIACOL do?

Used in cosmetics as a hair dye.

Is 4-NITROGUAIACOL safe?

Critical concern: no hazard classifications on record. It is banned in EU cosmetics.

beauty
industrial

4-NITROGUAIACOL

CAS 3251-56-7 · 100/100 · High conf.

Concern score

100/100Critical concern based on regulatory listings.

High confidence

4-NITROGUAIACOL in plain language

What it is: Also known as 2-Methoxy-4-nitrophenol · Phenol, 2-methoxy-4-nitro- · 3-METHOXY-4-HYDROXYNITROBENZENE · 3-Nitro-6-hydroxyanisole · 4-06-00-05627 (Beilstein Handbook Reference) · 4-Hydroxy-3-methoxynitrobenzene
Show all 14 names
4-NITRO-2-METHOXYPHENOL · Guaiacol, 4-nitro- · Izlvflobtpurlp-uhfffaoysa-n · InChI=1/C7H7NO4/c1-12-7-4-5(8(10)11)2-3-6(7)9/h2-4,9H,1H · Mononitro guaiacol · Phenol, o-methoxy-p-nitro- · UNII-41ITO2N6UT · o-Methoxy-p-nitrophenol
What it does: Used in cosmetics as a hair dye.
Hair dyeing
Colourant
Is it a concern?: Critical concern: no hazard classifications on record. It is banned in EU cosmetics.

Why it's flagged

2-Methoxy-4-nitrophenol (4-Nitroguaiacol) and its salts, when used as a substance in hair dye products is prohibited in cosmetic products under Annex II of the EU Cosmetics Regulation (EC) 1223/2009.

RestrictedEU EC — banned

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 II — prohibited
EU prohibited in cosmetics

Recorded in these product areas

Found in consumer products
Industrial

EUEC
Annex II of EU Cosmetics Regulation (EC) 1223/2009: substances prohibited in cosmetic products.
banned
View source →

EUCosIngActive2 entries
- Cosmetics Regulation annex II / ref 1251.Source →
- Restriction: II/1251Source →
USEPAcommercial use observedEPA CPDat observed this chemical in 0 composition records across product categories including unclassified products. EPA CPDat classifies this chemical for functional uses including Dye.
- EPA CPDat observed this chemical in 0 composition records across product categories including unclassified products. EPA CPDat classifies this chemical for functional uses including Dye.Source →
USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
- openFDA substance registry classifies this ingredient as chemical.Source →

Expert safety opinions

No expert opinion on file for 4-NITROGUAIACOL. 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 4-NITROGUAIACOL yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

7 data sources

Where this comes from

CosIng
regulatory · updated 2026-09-23
Open →
EU CosIng Cosmetics Regulation Annexes
regulatory · updated 2010-10-21
Open →
EPA Chemical and Products Database
exposure · updated 2020-02-13
Open →
EPA DSSTox Identifiers
chemistry · updated 2025-12-29
Open →
FDA GSRS UNII
registry · updated 2026-02-26
Open →
openFDA Substance
registry · updated 2026-05-24
Open →
PubChem Live Enrichment
chemistry · updated 2026-05-17
Open →

Suitability

Context-specific fit derived from published classifications and the current ingredient evidence profile.

Fragrance avoidance

No fragrance-linked caution surfaced in the current profile.

Good fit

This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.

Where it has been recorded

How often EPA CPDat has listed 4-NITROGUAIACOL in a product composition. These are source records, not Greenveil catalog products.

Named organisations

Typical roles

Hair dyeingColourant

See products using 4-NITROGUAIACOL →