Formaldehyde — Allergy Risk & Safety Profile

Name: Is Formaldehyde Safe? Allergy Risk & Alternatives
Creator: SkinDetekt

INCI: FORMALDEHYDE

Also known as: Formalin, Methanal

🔴 High Risk

Key Facts

CAS Number: 50-00-0
Category: preservative
Risk Level: high
Common Allergen: Yes
EU Status: Restricted
Max Concentration: 0.1% (free formaldehyde)
Found In: nail polish, hair straightening

Is Formaldehyde safe in cosmetics?

Formaldehyde is rated high risk in cosmetic products. It is a known allergen that can cause contact dermatitis in sensitized individuals. Strong sensitizer and classified carcinogen (IARC Group 1). This ingredient is restricted under EU cosmetic regulations. Safer alternatives include Phenoxyethanol, Sodium Benzoate, Potassium Sorbate. Commonly found in nail polish, hair straightening.

What is Formaldehyde?

Known carcinogen and potent allergen. Rarely used directly but released by formaldehyde-releasing preservatives.

Allergy & Safety Information

Formaldehyde 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 Formaldehyde.

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.

Allergen Note: Strong sensitizer and classified carcinogen (IARC Group 1).

About Preservative Ingredients

Preservatives prevent microbial growth in water-containing cosmetic formulas. Without them, products would spoil within days. However, preservatives are among the most common causes of allergic contact dermatitis — they must be present in high enough concentrations to be effective, yet that same efficacy can irritate sensitised skin.

Relevance for Formaldehyde: If you react to one preservative, you may be cross-reactive to others in the same chemical family (e.g., isothiazolinones, formaldehyde releasers, or parabens). Checking the full preservative profile of every product you use is the most reliable way to identify your personal trigger.

How to Identify Formaldehyde 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 Formaldehyde, 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: Nail polish, Hair straightening. These product categories are the most common sources of Formaldehyde exposure based on formulation data.

Not sure if your products contain Formaldehyde? Paste the ingredient list into the free ingredient checker to scan for Formaldehyde and other allergens automatically.