Science
Mechanism of Action
Upon contact with water, Phthalic Anhydride undergoes hydrolysis, forming phthalic acid. This resulting acid is a significant skin irritant, capable of inducing contact dermatitis characterized by redness, a burning sensation, and potentially leading to dryness, chapping, or urticaria with continued exposure. The ingredient also carries a demonstrable risk of inducing skin sensitization.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
Phthalic Anhydride is consistently classified as a hazardous substance by regulatory bodies and safety organizations. There is no scientific basis or industry practice to suggest this ingredient is commonly misrepresented as beneficial in skincare; instead, its adverse effects are widely acknowledged.
The Formula
Formulation
Stability
This ingredient is hydrolytically unstable, reacting slowly with water to form phthalic acid. Its half-life in water is approximately 30.5 seconds at pH 7.24 and 61 seconds at pH 6.8, demonstrating rapid degradation in aqueous environments, particularly at common formulation pH levels (4, 7, and 9).
Conflicts
- Water
- Alkalis
- Alcohols
- Oxygen
- Oxidizing agents
- Strong acids
- Strong bases
- Reducing agents
- Copper oxide (on heating)
- Sodium nitrite (on heating)
Safety
Safety Profile
The European Union (EU GHS) classifies Phthalic Anhydride as harmful if swallowed, causing serious eye damage, skin irritation, and potentially allergic skin reactions. It can also lead to allergy or asthma symptoms if inhaled. While the EPA has not classified it for carcinogenicity, and the FDA monitors phthalates (derivatives) in cosmetics, stating no evidence of risk from phthalates currently used, Phthalic Anhydride itself is explicitly recognized as a hazardous substance. EWG rates it as 'Unacceptable' for product use, and occupational exposure limits are extremely low (e.g., TLV of 0.002 mg/m³).
Your Skin
Skin Compatibility
Our Assessment
Verdict
Phthalic Anhydride is a highly irritating and sensitizing hazardous substance with no demonstrable benefits for skin, rendering it entirely unsuitable for precision skincare formulations.
Related
Similar Ingredients
Finding similar ingredients…