Ingredient Dictionary

THIOGLYCERIN

Monothioglycerol is a thiol that is glycerol in which one of the primary hydroxy groups is replaced by a thiol group.

Definition

Monothioglycerol is a thiol that is glycerol in which one of the primary hydroxy groups is replaced by a thiol group. It has a role as a reducing agent and a vulnerary. It is a member of propane-1,2-diols and a thiol.

Source: PubChem

US FDA substance register · UNII AAO1P0WSXJ · registered name MONOTHIOGLYCEROL · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Softens and loosens the outer layerKERATOLYTICReduces other ingredientsREDUCINGCurls or straightens hairHAIR WAVING OR STRAIGHTENINGDissolves hair to remove itDEPILATORY

Safety & regulatory references

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

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

Official labels & definitions

JCIA labelling name チオグリセリン: 本品は、次の化学式で表される含硫多価アルコールである。

Source: JCIA labelling names (Japan)

Names & identifiers

THIOGLYCERININCI티오글리세린Korean label name (MFDS standard)1,2-Propanediol, 3-mercapto-SynonymチオグリセリンJapanese labelling name

CAS No.chemical registry number: 38098-46-3
CAS No.chemical registry number: 96-27-5
EC No.EU chemical inventory number: 202-495-0
EC No.EU chemical inventory number: 253-777-5
DTXSIDUS EPA chemical ID: DTXSID5046512
DTXCIDUS EPA compound ID: DTXCID3026512

IUPAC: 3-Sulfanylpropane-1,2-diol
Molecular formula: C3H8O2S
Molecular weight: 108.16 g/mol

Measured properties

Appearance: Liquid · Water-white liquid, Soluble in water, [Hawley] Yellowish hygroscopic liquid, Slightly soluble in water, [Merck Index] Colorless viscous liquid with a stench, [MSDSonline]
Odour: SLIGHT SULFIDIC
Boiling point: 118 °C @ 5 MM HG
Solubility: SLIGHTLY SOL IN WATER, MISCIBLE WITH ALCOHOL, INSOL IN ETHER · VERY SOL IN ACETONE, SLIGHTLY SOL IN BENZENE
Density: 1.295
Initial boiling point and range: 248 ℃
Flash point: 149 ℃
Relative density: 1.2409
Molecular weight: 108.16

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 15 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.

Depilatory (EPA)3
Hair waving or straightening (EPA)3
Reducing agent3
Preservative2
Pharmaceutical (EPA)2
Heat stabilizer1
Antioxidant1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

2 skin studies and 1 eye studies are on record.

Classed as moderate1

The study conclusions largely agree (100%). These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 3 studies

Category 6.3A (Category 2)
Skin Irritation · Read Across
SkinSens1
Skin Sensitization · QSAR Predicted
Category 6.4A (Category 2A)
Eye Irritation · Read Across