Iodopropynyl Butylcarbamate
Also known as IPBC, 3-Iodo-2-propynyl n-butylcarbamate, 3-Iodo-2-propynylbutylcarbamate, Iodopropynyl butylcarbamate
“EU CosIng says: restricted.”
IPBC is a biocide-class preservative active against fungi and bacteria, used in cosmetics since the 1990s. The CIR Expert Panel (1996, published IJT 17(S5):1-37, 1998) concluded it is safe as a cosmetic ingredient at concentrations up to 0.1% with a qualified finding (SQ), prohibiting use in aerosolized products due to inhalation toxicity concerns. A 2013 CIR re-review confirmed the 1998 conclusion was not reopened. Allergic contact sensitization is the primary safety concern: IPBC is identified as an emerging allergen with increasing prevalence in patch-test series. The EU imposes tiered product-type caps (0.02% rinse-off, 0.01% leave-on, 0.0075% deodorants) far below the CIR 0.1% ceiling, reflecting the EU's more precautionary approach based on SCCS assessment of iodine load and sensitization potential.
Broad-spectrum preservative effective against fungi, bacteria, and yeast at low concentrations
Effective at very low use concentrations (typically 0.01–0.05%), well below CIR ceiling
Widely used in rinse-off and leave-on cosmetic formulations as an alternative to formaldehyde-releasing preservatives
- · Allergic contact dermatitis: identified as an emerging allergen with increasing prevalence in patch-test populations (Deza & Giménez-Arnau, 2017)
- · Inhalation toxicity: CIR and EU both prohibit use in aerosol/spray products due to inhalation risk data
- · Iodine load: EU restrictions include children-under-3 prohibition in leave-on and deodorant categories citing iodine absorption concerns
- · Prohibited in lip and oral hygiene products under EU Annex V
- · Not permitted in leave-on products for children under 3 years of age
- · 0.02% Annex V Entry 56: max 0.02% in rinse-off products. Not to be used in rinse-off products for children under 3 years of age except bath products, shower gels and shampoo.
- · 0.01% Annex V Entry 56: max 0.01% in leave-on products (except deodorants/antiperspirants which are restricted to 0.0075%). Not to be used in leave-on products or deodorant/antiperspirant products for children under 3 years of age.
- · 0% Annex V Entry 56: not permitted in oral hygiene products, lip products, or any product for children under 3 years of age (leave-on and deodorant/antiperspirant categories). Rinse-off prohibition for children under 3 applies except for bath products, shower gels, and shampoo.
- · 0% Annex V Entry 56: not to be used in aerosol/spray products (prohibition consistent with CIR finding; inhalation toxicity risk).
CIR Quick Reference Table (12/2017, revised 07/2018) — Iodopropynyl Butylcarbamate row: Finding=SQ, Citation=IJT 17(S5):1-37, 1998
“Iodopropynyl Butylcarbamate | SQ | safe for use at 0.1%; should not be used in products intended to be aerosolized | IJT 17(S5):1-37, 1998”— QRT-122017revised072018.pdf, Iodopropynyl Butylcarbamate row (I section)
EU Cosmetics Regulation 1223/2009 Annex V — Entry 56: Iodopropynyl Butylcarbamate (3-Iodo-2-propynylbutylcarbamate), CAS 55406-53-6, EC 2…
“Entry 56, 3-Iodo-2-propynylbutylcarbamate (Iodopropynyl butylcarbamate), CAS 55406-53-6, EC 259-627-5; rinse-off products 0.02%”— EU Reg 1223/2009 Annex V, Entry 56