Common Name(s): Potassium butylparaben,potassium butylparaben,paraben ester preservative,antimicrobial preservation active

CAS Number: N/a

DESCRIPTION

What It Does: Protects cosmetic formulations from bacterial, fungal, and yeast contamination through paraben ester mechanism — maintaining product safety and shelf life throughout the product's use period.

Why It's Used: Preservation is a non-negotiable safety requirement for water-containing cosmetics — microbial contamination causes product degradation, active decomposition, and risk of pathogenic growth that could cause skin infection in users.

How It Works: Parabens inhibit microbial growth by entering cells as unionised acids (pka ~8.5) through the lipid membrane, then ionising intracellularly disrupting atp synthesis and inhibiting key enzymes. the ester chain length determines membrane partitioning: longer chain (propyl, butyl) → higher antimicrobial potency and lipophilicity.

Typically Found In: Preserved cosmetics

TECHNICAL DETAILS

Primary Category: Active ingredient – cosmetic active

Secondary Functions: Skin conditioning

Application Areas:

Typical Concentration Range: Per eu annex v limits

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Good safety profile at recommended concentrations. ewg score: 1–2.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Long-chain parabens (butyl, propyl, isobutyl, isopropyl) are restricted in eu cosmetics — propylparaben limited to 0.14% alone or 0.19% with methylparaben; butylparaben prohibited in infant/toddler products. the shorter chains (methyl, ethyl) are generally permitted at up to 0.4% alone. endocrine disruption concern relates to weak estrogenic activity at high exposures.

Last Verified: Eu regulation 1223/2009 annex v,potassium butylparaben preservative regulatory review

Primary Sources: 2026-03-22