Thioglycolic Acid — Allergy Risk & Safety Profile
INCI: THIOGLYCOLIC ACID
Key Facts
- CAS Number
- 68-11-1
- Category
- active
- Risk Level
- high
- Common Allergen
- Yes
- Found In
- hair removal cream, perm solution
Is Thioglycolic Acid safe in cosmetics?
Thioglycolic Acid is rated high risk in cosmetic products. It is a known allergen that can cause contact dermatitis in sensitized individuals. Commonly found in hair removal cream, perm solution.
What is Thioglycolic Acid?
Chemical hair remover/straightener. Strong irritant and sensitizer.
Allergy & Safety Information
Can cause chemical burns if left on too long. Common cause of contact dermatitis. Always patch test.
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 Active Ingredient Ingredients
Active ingredients are formulated to produce a specific skin benefit — exfoliation, brightening, anti-ageing, or acne treatment. They work by interacting directly with skin biology, which also means they carry higher irritation potential than passive ingredients like emollients or thickeners.
Relevance for Thioglycolic Acid: Actives often require an adjustment period during which temporary redness, dryness, or sensitivity is normal. However, persistent reactions after 4–6 weeks of use, or reactions that worsen rather than improve, suggest true intolerance. Introduce only one active at a time to identify the cause of any reaction.
How to Identify Thioglycolic Acid 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 Thioglycolic Acid, 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 removal cream, Perm solution. These product categories are the most common sources of Thioglycolic Acid exposure based on formulation data.
Not sure if your products contain Thioglycolic Acid? Paste the ingredient list into the free ingredient checker to scan for Thioglycolic Acid and other allergens automatically.
Frequently Asked Questions
Is Thioglycolic Acid safe for sensitive skin?
Thioglycolic Acid is a known allergen and is generally not recommended for sensitive skin. Consider patch testing before use.
What products contain Thioglycolic Acid?
Thioglycolic Acid is commonly found in hair removal cream, perm solution.
What does Thioglycolic Acid do in cosmetics?
Thioglycolic Acid functions as a active in formulations.
Related Guides
Top 10 Cosmetic Allergens
Is Thioglycolic Acid on the list? See the full clinical ranking.
Anti-Aging for Sensitive Skin
The safest actives for sensitive skin and how to use them.
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 Thioglycolic Acid causing YOUR skin reactions?
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