3,3-Bis(4-hydroxyphenyl)phthalide (Phenolphthalein (INN))
Other
Avoid
CAS Number: 77-09-8
About 3,3-Bis(4-hydroxyphenyl)phthalide (Phenolphthalein (INN))
Phenolphthalein — the classic pH indicator that turned out to be a carcinogen and mutagen. Once used in laxatives, now banned in cosmetics.
Detailed Analysis
Phenolphthalein is the iconic acid-base indicator (colorless in acid, pink in base) that was historically used as an over-the-counter laxative before being withdrawn due to carcinogenicity concerns. GHS classifications include H350 (may cause cancer), H341 (suspected mutagen), H361f (suspected of damaging fertility), H317 (skin sensitizer), and H372 (organ damage from repeated exposure). It is classified as IARC Group 2B (possibly carcinogenic). The NTP found clear evidence of carcinogenicity in rodents. EU Annex II bans it from cosmetics.
Known Concerns
- ⚠ EU banned (Annex II)
- ⚠ H350 — may cause cancer
- ⚠ H341 — suspected mutagen
- ⚠ suspected reproductive toxicity (H361f)
- ⚠ skin sensitizer (H317)
- ⚠ organ damage from repeated exposure (H372)
- ⚠ IARC Group 2B
Safety Score
Avoid
Based on EU regulatory data, published safety research, and ingredient function analysis.
References
EU CosIng Database
European Commission cosmetic ingredient registry
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