Good Active Ingredient NOAEL Data GHS Classified Dermal Penetration

Sulfur

INCI: SULFUR

CAS Number
7704-34-9
Function
Keratolytic; antimicrobial; antifungal; sebum regulator; acne-control active; structurally critical for keratin disulfide bonds in hair and nail; traditional balneotherapy active for psoriasis and atopic dermatitis
Safety Rating
GOOD

Regulatory Status

🇪🇺 EU Status permitted
🇺🇸 US Status permitted
US Notes FDA GRAS OTC drug: acne treatment 3-10% standalone (21 CFR 333.310(e)) or 3-8% with resorcinol 2%; dandruff/seborrheic dermatitis 2-5% (OTC Monograph M032). Permitted combinations: resorcinol 2%, resorcinol monoacetate 3%, salicylic acid 1.8-3%. CIR Expert Panel deferred evaluation to FDA OTC drug assessment.

For full compliance data across 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
not established
Dermal Absorption
low
Sensitization
none

Calculate MoS for your specific formulation with the MoS Calculator.

Toxicological Studies

9 study endpoints found for Sulfur. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.

Endpoint Value Route Species Study Type Source
NOAEL 400 mg/kg bw/day dermal rat dermal REACH
NOAEL 1000 other oral rat oral REACH
NOAEL 1000 other oral rat oral REACH
LOEL 9.3 mg/kg bw/day oral rat oral REACH
LOEL 80 other oral guinea pig oral REACH
NOAEL 200 mg/kg bw/day oral guinea pig oral REACH
NOAEL 120 mg/kg bw/day dermal cat dermal REACH
LOAEL 120 other oral guinea pig oral REACH
NOAEL 40 other oral guinea pig oral REACH

GHS Hazard Classification

Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.

Short-term Exposure Effects
The substance is irritating to the eyes, skin and respiratory tract. Inhalation of the powder may cause inflammation of the nose and respiratory tract.
Long-term Exposure Effects
Repeated or prolonged contact with skin may cause dermatitis. The substance may have effects on the respiratory tract. This may result in chronic bronchitis.
Routes of Exposure
The substance can be absorbed into the body by inhalation and by ingestion.

Dermal Penetration Profile

Skin absorption and penetration characteristics of Sulfur, relevant to systemic exposure and MoS calculations.

Absorption %
0.5-2%
Penetration Level
surface
Penetration Depth
stratum corneum
Molecular Weight
32.1 Da
Log P
n/a
Systemic Absorption
minimal
Topical Bioavailability
0.2-1%
Safety Margin Factor
minimal
Vehicle Dependent
Yes — absorption varies by formulation

Source: CIR

Expert Verdict

Elemental sulfur is permitted in the EU under Regulation 1223/2009 with no specific concentration limits and approved as FDA GRAS for OTC acne (3-10%) and dandruff treatment (2-5%). Primary hazard is skin irritation (Category 2); dermal absorption is low (1.8-10%) with no systemic absorption through intact skin, and no sensitization potential.

⚠️
Concern Level: Low

Regulatory Flags

skin-irritant keratolytic otc-drug-us fda-grase odor-concern anti-acne anti-dandruff fda-deferred-cir

Frequently Asked Questions

Is Sulfur safe in cosmetics?

Elemental sulfur is permitted in the EU under Regulation 1223/2009 with no specific concentration limits and approved as FDA GRAS for OTC acne (3-10%) and dandruff treatment (2-5%). Primary hazard is skin irritation (Category 2); dermal absorption is low (1.8-10%) with no systemic absorption through intact skin, and no sensitization potential. The EU classifies Sulfur as "permitted". Safety rating: GOOD. 9 toxicological study endpoint(s) are available in our database.

Is Sulfur allowed in the EU?

Sulfur EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.

What does Sulfur do in cosmetics?

Sulfur functions as: Keratolytic; antimicrobial; antifungal; sebum regulator; acne-control active; structurally critical for keratin disulfide bonds in hair and nail; traditional balneotherapy active for psoriasis and atopic dermatitis. It is classified as a Active Ingredient in our database. CAS number: 7704-34-9.

What is the Margin of Safety for Sulfur?

not established The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

What is the NOAEL for Sulfur?

The NOAEL (No Observed Adverse Effect Level) for Sulfur is 400 mg/kg bw/day based on a dermal study via dermal route in rat. A total of 9 study endpoints are available. Source: REACH.

Compliance Tools

Check Sulfur compliance across multiple jurisdictions:

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Ingredient Decoder
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82 Allergen Checker
Check for EU declarable fragrance allergens
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Substance Compliance
Check compliance across 55 jurisdictions
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
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Heavy Metal Limits
Compare limits across jurisdictions

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