Methenamine
AKA “Hexamethylenetetramine, 100-97-0, Hexamine, Urotropine, Urotropin, 1, 3, 5, 7-Tetraazaadamantane, Uritone, HMTA, Hexamethylenamine
Preservative
Ingredient Facts
Methenamine
AKA: Hexamethylenetetramine, 100-97-0, Hexamine, Urotropine, Urotropin, 1, 3, 5, 7-Tetraazaadamantane, Uritone, HMTA, Hexamethylenamine
Preservative · Antimicrobial · EWG: 4
Synthetic
Preservative
Not Clean
1,3,5,7-Tetraazatricyclo[3.3.1.1(3,7)]decane
Solubility greater than or equal to 100 mg/mL at 68 °F (NTP, 1992)
Formula
C6H12N4
Mol. Weight
140.19
CAS #
100-97-0
Form
Liquid
State
Hexamethylenetetramine appears as odorless white crystalline powder or colorless lustrous crystals. Sublimes in a vacuum at about 505 °F with some decomposition. Solutions are strong bases (pH of 0.2
See origin →
Functions
Antimicrobial
Keeps your product from growing bacteria, mold, or yeast. Without these, that jar of cream becomes a petri dish in about a week.
Preservative
Keeps your product from growing bacteria, mold, or yeast. Without these, that jar of cream becomes a petri dish in about a week.
Fights Bacteria
Traditional Use
Synthetic compound developed in the late 19th century originally for medical use as an antimicrobial agent; adopted in cosmetics as a preservative alternative in select formulations.
Skin Types
all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
EWG
4
CIR
Safe as used
Pregnancy
Caution
CIR Safety Findings
medical-approval
all-shades-safe
Concentration Guide
0.15%
0%0%
Reg. Limit
EU regulatory limit: 0.15%. Source: EU Cosmetics Regulation (EC) 1223/2009, Annex V (Preservatives), Entry 30.
Regulatory Status
USApermitted
EUpermitted
JAPANpermitted
CANADApermitted
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR