Quaternium-15

kwah-TER-nee-um FIF-teen

Preservative 2/10 Safety Not CGAvoid Synthetic Vegan

What Is Quaternium-15?

A formaldehyde-releasing preservative that slowly releases formaldehyde to prevent bacterial growth in hair and cosmetic products. One of the strongest formaldehyde releasers used.

Source: Synthetic quaternary ammonium compound

Origin: Synthetic

Also known as: Dowicil 200, N-(3-Chloroallyl)hexaminium Chloride

What Does Quaternium-15 Do to Your Hair?

Releases formaldehyde continuously to provide broad-spectrum antibacterial and antifungal preservation. Effective at very low concentrations. However, it releases more formaldehyde than most other formaldehyde-releasing preservatives.

Best For

None recommended

Not Recommended For

All hair types, especially sensitive scalp, eczema-prone

Concentration Matters

0.02-0.2% in products

Hair Type Compatibility

1A Straight Fine
1B Straight Medium
1C Straight Coarse
2A Wavy Fine
2B Wavy Medium
2C Wavy Coarse
3A Curly Loose
3B Curly Tight
3C Curly Corkscrew
4A Coily S-Shaped
4B Coily Z-Shaped
4C Coily Tight

Method Compatibility

Curly Girl (CG) Method: Avoid
CG Avoid

Safety & Regulation

2/10
AvoidCautionSafe

One of the strongest formaldehyde-releasing preservatives. Formaldehyde is classified as a known human carcinogen. The American Contact Dermatitis Society named it Allergen of the Year in 2015. A leading cause of preservative-related contact dermatitis.

FDA Status: Generally Recognized As Safe

FDA permits use but formaldehyde is classified as a known carcinogen by IARC and NTP.

EWG Score: 8/10

HairAide Verdict

Strongly avoid. Releases more formaldehyde than most other preservatives in this category. Named Allergen of the Year by dermatologists. Safe preservative alternatives are readily available.

Products That Contain Quaternium-15

Some shampoos and conditioners (being phased out)

Alternatives to Quaternium-15

If you want to avoid Quaternium-15, look for products with these ingredients instead:

Phenoxyethanol, Benzyl Alcohol, Sodium Benzoate

Frequently Asked Questions

Is Quaternium-15 safe for hair?

Quaternium-15 has a safety rating of 2/10 and may be problematic for many hair types. One of the strongest formaldehyde-releasing preservatives. Formaldehyde is classified as a known human carcinogen. The American Contact Dermatitis Society named it Allergen of the Year in 2015. A leading cause of preservative-related contact dermatitis.

Is Quaternium-15 bad for curly hair?

Quaternium-15 is not CG-method approved. Curly hair types may want to avoid this ingredient or use products containing it sparingly.

Is Quaternium-15 CG-method approved?

No, Quaternium-15 is not approved for the Curly Girl method.

What can I use instead of Quaternium-15?

Some alternatives to Quaternium-15 include: Phenoxyethanol, Benzyl Alcohol, Sodium Benzoate

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