beauty

2-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), when used as a substance in hair dye products

100/100 · High conf.

Concern score

100/100Critical concern based on regulatory listings.

High confidence

2-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), when used as a substance in hair dye products in plain language

What it is: On cosmetic ingredient lists it appears as “Acid yellow 73”.
Also known as Acid yellow 73 · Acid yellow 73 sodium salt · CI 45350
What it does: We don't have a plain-language description for 2-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), when used as a substance in hair dye products yet.
Is it a concern?: Critical concern: no hazard classifications on record. It is banned in EU cosmetics.

Why it's flagged

2-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), 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

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

EUCosIngActiveCosmetics Regulation annex II / ref 1332.
- Cosmetics Regulation annex II / ref 1332.Source →

Expert safety opinions

No expert opinion on file for 2-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), when used as a substance in hair dye products. 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-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), when used as a substance in hair dye products yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

2 data sources

Where this comes from

CosIng
regulatory · updated 2026-09-23
Open →
EU CosIng Cosmetics Regulation Annexes
regulatory · updated 2013-05-07
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.

Catalog

Found in these products

Their ingredient lists include 2-(6-Hydroxy-3-oxo-(3H)xanthen-9-yl)benzoic acid; Fluorescein and its disodium salt (Acid Yellow 73 sodium salt; CI 45350), when used as a substance in hair dye products; each product's own rating depends on its whole formula, so it is shown on the product page, not here.

See all 10 →Find products without it →