OriginSynthesized from o-phenylenediamine through nitration using nitric acid and sulfuric acid catalysts. Produced via electrophilic aromatic substitution to introduce the nitro group into the benzene ring structure.
4-nitro-o-phenylenediamine (CI 76020)
Solubility less than 1 mg/mL at 68.9 °F (NTP, 1992)
Formula
C6H7N3O2
Mol. Weight
153.14
CAS #
99-56-9
Form
Liquid
State
4-nitro-o-phenylenediamine appears as dark red needles or red solid. (NTP, 1992)
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
No
Allergen Warning
⚠️ PPD (Hair Dye)
Functions
Hair Dyeing
Reduces Inflammation
Antioxidant Protection
Fights Bacteria
Colors Hair
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
4
CIR
Safe as used
Pregnancy
No
CIR Safety Findings
Not Phototoxic
Lab (in vitro) test found no phototoxicity in the CIR safety assessment (CIR 925)
Mixed Eye Irritation Results
2 studies / 1 irritating / 1 mixed / reactions slight to mild (CIR 198 and 925)
Mixed Skin Irritation Results
5 studies / 1 mixed / 4 not irritating / reactions slight (CIR 198 and 925)
Mixed Sensitization Results
8 studies / 3 sensitizing / 5 not sensitizing (CIR 198 and 925)
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