Moderate Cosmetic Ingredient GHS Classified Sensitization Data

Potassium Metabisulfite

INCI: POTASSIUM METABISULFITE

CAS Number
16731-55-8
Function
Reducing agent; Antioxidant; Preservative (hair waving/straightening systems)
Safety Rating
MODERATE

Regulatory Status

🇪🇺 EU Status restricted
🇺🇸 US Status permitted
US Notes Recognized in 21 CFR; CIR concluded safe as used in cosmetics. Also FDA-listed for food use

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

Safety Data

Margin of Safety (MoS)
adequate
Dermal Absorption
low
Sensitization
high

Calculate MoS for your specific formulation with the MoS Calculator.

GHS Hazard Classification

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

Signal Word
DANGER
Pictograms
corr
Hazard Statements
Causes serious eye damage
Short-term Exposure Effects
The substance is corrosive to the eyes. The substance is irritating to the skin, respiratory tract and gastrointestinal tract. Exposure could cause asthma-like reactions or urticaria in sensitive persons.
Long-term Exposure Effects
Repeated or prolonged inhalation may cause asthma-like symptoms. The substance may have effects on the skin.
Routes of Exposure
The substance can be absorbed into the body by inhalation and by ingestion.

Sensitization Profile

Contact sensitization data for Potassium Metabisulfite based on clinical patch test studies and IFRA standards.

Sensitization Rate
low
Allergen Class
preservative
EU Allergen Listed
no
Patch Test Positive Rate
0.2%
Cross-reactivity Group
none
Reaction Type
contact-dermatitis

Source: IVDK; SCCS

Expert Verdict

Known sulfite allergen with mandatory labeling in many jurisdictions; in vitro genotoxicity concerns attributed to bisulfite form, but CIR concluded the sulfite form predominates in cosmetic formulations with low in vivo relevance. Annex III restrictions must be strictly followed.

⚠️
Concern Level: High

Regulatory Flags

potential-allergen preservative ifra_fragrance fda_food_additive

Frequently Asked Questions

Is Potassium Metabisulfite safe in cosmetics?

Known sulfite allergen with mandatory labeling in many jurisdictions; in vitro genotoxicity concerns attributed to bisulfite form, but CIR concluded the sulfite form predominates in cosmetic formulations with low in vivo relevance. Annex III restrictions must be strictly followed. The EU classifies Potassium Metabisulfite as "restricted". Safety rating: MODERATE.

Is Potassium Metabisulfite allowed in the EU?

Potassium Metabisulfite EU regulatory status: restricted. This is based on EU Regulation 1223/2009 and its amendments.

What does Potassium Metabisulfite do in cosmetics?

Potassium Metabisulfite functions as: Reducing agent; Antioxidant; Preservative (hair waving/straightening systems). It is classified as a cosmetic ingredient in our database. CAS number: 16731-55-8.

What is the Margin of Safety for Potassium Metabisulfite?

adequate 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.

Is Potassium Metabisulfite classified as hazardous under GHS?

Potassium Metabisulfite carries a GHS signal word of "DANGER". Hazard statements: Causes serious eye damage. This classification is based on the ILO/WHO International Chemical Safety Card and ECHA C&L inventory data. Note: GHS classification applies to the pure substance — at cosmetic use concentrations, hazard thresholds may not be met.

Compliance Tools

Check Potassium Metabisulfite 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
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
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Heavy Metal Limits
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