Korean: 시스테인 · Functions: antioxidant, antistatic, fragrance, hair conditioning, hair waving or straightening, reducing
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 17, 2026
No specific rule on file.
No specific rule on file. The FDA regulates few cosmetic ingredients by name; no rule does not mean approval.
How Cysteine is treated in 1 more market, 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 |
|---|---|---|
| TW Taiwan | Restricted | MFDS summary (Korean): ※ 染髮、脫色、脫染及燙髮產品之應刊載之注意事項，應依衛生福利部公告刊載之。 ※ 染髮產品之限量標準：係指該成分依產品使用說明書混合後之最高允許使用量。 ※ 化粧品之外包裝或容器，應明顯標示本表所列成分之注意事項。因外包裝或容器表面積過小或其他特殊情形致不能標示者，應於標籤、仿單或以其他方式刊載之。 ※ 本表所稱之口腔製劑，包含非藥用牙膏、漱口水類及美白牙齒類等化粧品。 ※ 化粧品宣稱效能者，須符合化粧品標示宣傳廣告涉及虛偽誇大或醫療效能認定準則規定。 * 단서조항 : ※ 染髮、脫色、脫染及燙髮產品之應刊載之注意事項，應依衛生福利部公告刊載之。 ※... |
Source: MFDS cosmetic ingredient use restrictions — overseas regulations · checked Oct 17, 2026
Cysteine 시스테인
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.
An amino acid used as a skin conditioner.
We found no specific rule for it in the EU's CosIng records. That is not an approval or a safety statement.
In Korea's MFDS records it is listed as “Restricted” (MFDS — cosmetic ingredient use restrictions). A restricted ingredient is allowed within the stated conditions.
We found no specific rule for it in the FDA's records. That is not an approval or a safety statement.
The EU's CosIng inventory lists its functions as: antioxidant, antistatic, fragrance, hair conditioning, hair waving or straightening, reducing.
Korea's MFDS standard Korean name is 시스테인.
24+ products we checked list it, for example Peach & Lily Advanced Rebound Bioglow Zombie Cream™, Missha Atelo Collagen 500 Power Plumping Cream, Aestura ATOBARRIER 365 HYDRO ESSENCE.