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KBeauty Verified™ — K-beauty checked against official records from Korea, the EU and the U.S.

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4-Hydroxyindole, when used as a substance in hair dye products

Korean: 4-하이드록시인돌 (염모제로 사용될때) · CAS 2380-94-1 ·

KR South Korea (MFDS)

No specific rule on file.

EU European Union (CosIng)

No specific rule on file.

US United States (FDA)

No specific rule on file. The FDA regulates few cosmetic ingredients by name; no rule does not mean approval.

Other markets

How 4-Hydroxyindole, when used as a substance in hair dye products is treated in 2 more markets, from the overseas cosmetic regulation database compiled by Korea's MFDS. Always confirm with the regulator of that country before selling there.

Market	Status	Conditions
BR Brazil	Prohibited only in certain forms or uses	MFDS summary (Korean): when used as a substance in hair dye products^염모제로 사용되는 경우에 한함
AR Argentina	Prohibited only in certain forms or uses	MFDS summary (Korean): when used as a substance in hair dye products^염모제로 사용되는 경우에 한함

Source: MFDS cosmetic ingredient use restrictions — overseas regulations · checked Oct 17, 2026

Also listed as

4-Hydroxyindole, when used as a substance in hair dye products 4-하이드록시인돌 (염모제로 사용될때)

Information only, not medical advice. Rules change — always check the linked official source. If you are pregnant, have a skin condition or allergies, ask a dermatologist or pharmacist.

Frequently asked questions

Is 4-Hydroxyindole, when used as a substance in hair dye products banned in the European Union?

We found no specific rule for it in the EU's CosIng records. That is not an approval or a safety statement.

Is 4-Hydroxyindole, when used as a substance in hair dye products banned in South Korea?

We found no specific rule for it in Korea's MFDS records. That is not an approval or a safety statement.

Is 4-Hydroxyindole, when used as a substance in hair dye products allowed in cosmetics in the U.S.?

We found no specific rule for it in the FDA's records. That is not an approval or a safety statement.

What is 4-Hydroxyindole, when used as a substance in hair dye products called on Korean labels?

Korea's MFDS standard Korean name is 4-하이드록시인돌 (염모제로 사용될때).

What is the CAS number of 4-Hydroxyindole, when used as a substance in hair dye products?

CAS 2380-94-1 (from official records).