p-Phenylenediamine — Allergy Risk & Safety Profile
INCI: P-PHENYLENEDIAMINE
Also known as: PPD, 1,4-Diaminobenzene
Key Facts
- CAS Number
- 106-50-3
- Category
- colorant
- Risk Level
- high
- Common Allergen
- Yes
- EU Status
- Restricted
- Max Concentration
- 2% (hair dye only)
- Found In
- hair dye, henna
Is p-Phenylenediamine safe in cosmetics?
p-Phenylenediamine is rated high risk in cosmetic products. It is a known allergen that can cause contact dermatitis in sensitized individuals. Can cause severe allergic reactions including facial swelling. Cross-reacts with many chemicals. This ingredient is restricted under EU cosmetic regulations. Safer alternatives include Iron Oxides, Mica, Titanium Dioxide. Commonly found in hair dye, henna.
What is p-Phenylenediamine?
Primary allergen in permanent hair dyes. One of the most potent contact allergens known.
Allergy & Safety Information
p-Phenylenediamine is classified as a high-risk ingredient. It is a known cause of allergic contact dermatitis. It is restricted or regulated in the EU. Individuals with sensitive skin or a history of contact allergies should avoid products containing this ingredient. A patch test is recommended before first use of any product containing p-Phenylenediamine.
This ingredient is classified as high risk from an allergenicity perspective. It is a recognised cause of allergic contact dermatitis with a relatively high sensitisation rate in patch-tested populations. People with a history of skin reactions to cosmetics, or with conditions such as eczema or sensitive skin, should exercise particular caution.
About Colorant / Pigment Ingredients
Colorants are used in makeup and some skincare products to provide colour. Inorganic colorants (iron oxides, ultramarines, chromium oxides) and organic dyes (CI numbers) are regulated by cosmetic authorities for purity and safety. Iron oxides naturally contain trace metal impurities including nickel, which can cause reactions in nickel-sensitised individuals.
Relevance for p-Phenylenediamine: Coal tar dyes (FD&C and D&C numbers) are more likely to cause reactions than inorganic mineral pigments. Azo dyes can release aromatic amines upon degradation. Metallic and shimmer pigments (mica, bismuth oxychloride) may contain trace nickel contamination.
How to Identify p-Phenylenediamine in Products
Cosmetic ingredients are listed by their INCI (International Nomenclature of Cosmetic Ingredients) name in descending order of concentration. To check whether a product contains p-Phenylenediamine, scan the ingredient list for its INCI name exactly as it appears above. Ingredients present at 1% or less may appear in any order after the 1% threshold.
Product types to prioritise checking: Hair dye, Henna. These product categories are the most common sources of p-Phenylenediamine exposure based on formulation data.
Not sure if your products contain p-Phenylenediamine? Paste the ingredient list into the free ingredient checker to scan for p-Phenylenediamine and other allergens automatically.
Cross-Reactions
If you react to p-Phenylenediamine, you may also react to:
Safer Alternatives
These ingredients serve a similar function with lower allergy risk:
Frequently Asked Questions
Is p-Phenylenediamine safe for sensitive skin?
p-Phenylenediamine is a known allergen and is generally not recommended for sensitive skin. Consider patch testing before use.
What products contain p-Phenylenediamine?
p-Phenylenediamine is commonly found in hair dye, henna.
What does p-Phenylenediamine do in cosmetics?
p-Phenylenediamine functions as a colorant in formulations. Can cause severe allergic reactions including facial swelling. Cross-reacts with many chemicals.
Related Guides
Top 10 Cosmetic Allergens
Is p-Phenylenediamine on the list? See the full clinical ranking.
How to Read Ingredient Labels
Decode INCI names and find hidden allergens in your products.
Find Your Skin Allergy Trigger
Step-by-step elimination method to identify your trigger.
Contact Dermatitis Guide
Symptoms, causes, patch testing, and treatment options.
Is p-Phenylenediamine causing YOUR skin reactions?
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