Ingredient Dictionary

THIMEROSAL

Thimerosal is an alkylmercury compound (approximately 49% mercury by weight) used as an antiseptic and antifungal agent.

Definition

Thimerosal is an alkylmercury compound (approximately 49% mercury by weight) used as an antiseptic and antifungal agent. It has a role as an antiseptic drug, a disinfectant, an antifungal drug and a drug allergen. It contains an ethylmercurithiosalicylate.

Source: PubChem

US FDA substance register · UNII 2225PI3MOV · registered name THIMEROSAL · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Thimerosal is the metallo-organic compound that conforms to the formula:

Cosmetic roles

Stops microbes growing in the productPRESERVATIVE

Safety & regulatory references

Banned: Canada
Restricted or banned: Canada · China · Taiwan
Allowed preservative: Taiwan · United Kingdom

Source: Health Canada Cosmetic Ingredient Hotlist · MFDS (Korea) cosmetic regulatory information · EU Cosmetics Regulation · Taiwan FDA cosmetic ingredients · UK cosmetics regulations (OPSS)

United States

Specific Limitations and Comments : Mercury compounds are readily absorbed through the skin on topical application and tend to accumulate in the body. They may cause allergic reactions, skin irritation, or neurotoxic problems. The use of mercury compounds in cosmetics is limited to eye area products at no more than 65 parts per million (0.0065 percent) of mercury calculated as the metal and is permitted only if no other effective and safe preservative is available. All other cosmetics containing mercury are adulterated and subject to regulatory action unless it occurs in a trace amount of less than 1 part per million (0.0001 percent) calculated as the metal and its presence is unavoidable under conditions of good manufacturing practice

European Union

Product Type, body parts : Eye products
Maximum concentration in ready for use preparation : 0.007% (of Hg) If mixed with other mercurial compounds authorized by this Regulation, the maximum concentration of Hg remains fixed at 0.007%
Wording of conditions of use and warnings : Contains Thiomersal

Source: MFDS (Korea) cosmetic regulatory information

Korea’s toxic-substance GHS classification: Danger · H410 (category 1) · H400 (category 1) · H373 (category 2) · +3 more

Source: Korea toxic substances GHS register (NIER)

EU Cosmetics Regulation, Annex V (allowed preservatives), entry 16 · maximum concentration 0.007% (of Hg) If mixed with other mercurial compounds authorized by this Regulation, the maximum concentration of Hg remains fixed at 0.007% · applies to Eye products

Source: EU allowed preservatives (Annex V)

Health Canada Cosmetic Ingredient Hotlist · prohibited in cosmetics

Source: Health Canada Cosmetic Ingredient Hotlist

Restriction V/16 · Other restriction: ban substances that deplete the ozone layer

Source: EU CosIng ingredient list

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

Names & identifiers

THIMEROSALINCI티메로살Korean label name (MFDS standard)Mercurate(1-), ethyl[2-(mercapto-.kappa.S)benzoato(2-)-.kappa.O]-, sodium (1:1)Synonym

CAS No.chemical registry number: 54-64-8
EC No.EU chemical inventory number: 200-210-4
DTXSIDUS EPA chemical ID: DTXSID3025540
DTXCIDUS EPA compound ID: DTXCID705540

IUPAC: Sodium ethyl[2-(sulfido-kappaS)benzoato]mercurate(1-)
Molecular formula: C9H9HgNaO2S
Molecular weight: 404.81 g/mol

Measured properties

Appearance: Mercury((o-carboxyphenyl)thio)ethyl, sodium salt is a light cream-colored crystalline powder with a slight odor: pH (1% aqueous solution) 6.7. Slight odor. (NTP, 1992) · Light cream-colored crystalline powder with a slight odor, [CAMEO]
Odour: Characteristic odor
Boiling point: 357.3
Melting point: 450 to 451 °F (decomposes) (NTP, 1992) · -38.87
Solubility: greater than or equal to 100 mg/mL at 66 °F (NTP, 1992) · 1 g/mL
Stability: Stable in air, but not in sunlight.
pH: pH (1% solution): 6.7 · 6.7
Melting/freezing point: 450~451 ℉
Water solubility: 1 g/㎖
Vapour density: 0.5 g/㎤
n-Octanol/water partition coefficient (Kow): -1.88

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 3 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.

Preservative3

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

5 skin studies and 2 eye studies are on record.

Classed as highly irritating1

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 7 studies

Classification not possible
Skin Irritation · Screening
Sh
Skin Sensitization · Authoritative
Category 8.2C (Category 1C)
Skin Irritation · Read Across
Category 6.5B (Category 1)
Skin Sensitization · Read Across
Category 1
Skin Sensitization · Screening
Category 8.3A (Category 1)
Eye Irritation · Read Across
Category 2B
Eye Irritation · Screening