Are there usage precautions?

항산화 및 보습 효과가 있는 성분으로, 피부 장벽을 강화하고 수분 손실을 방지합니다. 또한, 노화 방지 및 염증 완화에 도움을 줄 수 있습니다.

Ingredient Dictionary

ACETYL CYSTEINE

N-acetyl-L-cysteine is an N-acetyl-L-amino acid that is the N-acetylated derivative of the natural amino acid L-cysteine.

How much products actually contain

No product states its amount yet.

Of the products containing it, 2 list it before the 1% line and 1 after it (usually 1% or less).

Products using this ingredient

3 of 3 confirmed · likeliest to carry enough first

Definition

N-acetyl-L-cysteine is an N-acetyl-L-amino acid that is the N-acetylated derivative of the natural amino acid L-cysteine. It has a role as a ferroptosis inhibitor, a geroprotector, an antioxidant, an antiinfective agent, an antiviral drug, a radical scavenger, a vulnerary, an antidote to paracetamol poisoning, a mucolytic and a human metabolite. It is a N-acetyl-L-amino acid, an acetylcysteine and a L-cysteine derivative. It is a conjugate acid of a N-acetyl-L-cysteinate.

Source: PubChem

US FDA substance register · UNII WYQ7N0BPYC · registered name Acetylcysteine · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Slows spoilage by oxygenANTIOXIDANTKeeps skin in good condition (CosIng catch-all)SKIN CONDITIONING

Safety & regulatory references

Restricted: South Korea · Taiwan

Source: MFDS (Korea) cosmetic regulatory information

Japan

Maximum amount per 100 g (Cosmetics not used for mucosa and to be washed away) : 9.0 g
Maximum amount per 100 g (Cosmetics not used for mucosa and not to be washed away) : 9.0 g
Maximum amount per 100 g (Cosmetics that may be used for mucosa) :

Source: MFDS (Korea) cosmetic regulatory information

Not classified under Korea’s toxic-substance GHS list · existing chemical substance

Source: Korea toxic substances GHS register (NIER)

Other restriction: ban substances that deplete the ozone layer

Source: EU CosIng ingredient list

Reviewed by CIR: Safety Assessment of Amino Acid Alkyl Amides as Used in Cosmetics

Source: US Cosmetic Ingredient Review (CIR)

More data — names, identifiers, properties, test records, literature

Official labels & definitions

JCIA labelling name アセチルシステイン: 本品は、システイン（＊）をアセチル化したものであり、次の化学式で表される。

Source: JCIA labelling names (Japan)

Names & identifiers

ACETYL CYSTEINEINCI아세틸시스테인Korean label name (MFDS standard)アセチルシステインJapanese labelling name

CAS No.chemical registry number: 616-91-1
EC No.EU chemical inventory number: 210-498-3
DTXSIDUS EPA chemical ID: DTXSID5020021
DTXCIDUS EPA compound ID: DTXCID4021

IUPAC: N-Acetyl-L-cysteine
Molecular formula: C5H9NO3S
Molecular weight: 163.19 g/mol

Measured properties

Appearance: Solid · Crystals from water
Odour: SLIGHT ACETIC ODOR
Melting point: 109-110 · 109.5 °C
Solubility: 1 G IN 5 ML WATER, 4 ML ALC, PRACTICALLY INSOL IN CHLOROFORM & ETHER · Soluble in water, alcohol, hot isopropyl alcohol, methyl acetate, and ethyl acetate
Stability: Stable in ordinary light, stable at temp up to 120 °C, nonhygroscopic (oxidizes in moist air)
pH: 2 TO 2.75 (1 IN 100 ML) · 2~2.75 (1 IN 100 ML)
Dissociation constant: 9.52 (at 25 °C) · pKa= 3.24 (carboxylic acid moiety)
Colour: white
Melting/freezing point: 109 ℃
Initial boiling point and range: 371 ℃
Vapour pressure: 0.000011 ㎜Hg (@ 25 ℃, est.)
Water solubility: (200 g/L)
Vapour density: 5.63
Relative density: 1.48
n-Octanol/water partition coefficient (Kow): -0.66 (est.)
Molecular weight: 163.21

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: PubChem · KOSHA safety data sheets (Korea)

What products actually use it for

What the 5 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

Softener and conditioner3
Antioxidant2

Source: US EPA CompTox dashboard