Ask KBeauty Verified™

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

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ChatGPT: 2 Claude: 0 Google · Gemini: 0 Perplexity: 0 Meta AI: 0 Amazon: 0 Others: 0

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ChatGPT2

Claude0

Google · Gemini0

Perplexity0

Meta AI0

Amazon0

Others0

Named by what the crawler says it is; look-alikes we detect are counted under Others. Google · Gemini includes Googlebot, Google’s search crawler, whose index Google also uses for its AI features; other search engines and bots are in Others. AI visibility →

Cysteine HCl

Korean: 시스테인에이치씨엘 · Functions: antioxidant, hair conditioning, hair waving or straightening, reducing

KR South Korea (MFDS)

Restricted MFDS restricted ingredients

Conditions (official MFDS text, Korean):
* 배합한도 : 퍼머넌트웨이브용 제품에 시스테인으로서 3.0~7.5% (다만, 가온2욕식 퍼머넌트웨이브용 제품의 경우에는 시스테인으로서 1.5～5.5%, 안정제로서 치오글라이콜릭애씨드 1.0%를 배합할 수 있으며, 첨가하는 치오글라이콜릭애씨드의 양을 최대한 1.0%로 했을 때 주성분인 시스테인의 양은 6.5%를 초과할 수 없다)

Source: MFDS — cosmetic ingredient use restrictions · checked Oct 16, 2026

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.

Also listed as

Cysteine HCl 시스테인에이치씨엘

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.