Formaldehyde
molecular structure · PubChem
AKA: Formalin, Methanal, 50-00-0, Formol, Formic aldehyde, Methylene oxide, Oxomethane, Oxymethylene, Methyl aldehyde
Allergen Warning
⚠️ Formaldehyde
Synthetic
Preservative
Not Clean
Formaldehyde is a highly reactive aldehyde gas formed by oxidation or incomplete combustion of hydrocarbons. In solution, it has a wide range of uses: in the manufacture of resins and textiles, as a disinfectant, and as a laboratory fixative or preservative. Formaldehyde solution (formalin) is considered a hazardous compound, and its vapor toxic. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p717) -- Pubchem; The chemical compound formaldehyde (also known as methanal), is a gas with a pungent smell. It is the simplest aldehyde. Its chemical formula is H2CO. Formaldehyde was first synthesized by the Russian chemist Aleksandr Butlerov in 1859 but was conclusively identified by August Wilhelm van Hofmann in 1867. Although formaldehyde is a gas at room temperature, it is readily soluble in water, and it is most commonly sold as a 37% solution in water called by trade names such as formalin or formol. In water, formaldehyde polymerizes, and formalin actually contains very lit
Solubility Miscible (NIOSH, 2024)
Formula
CH2O
Mol. Weight
30.03
CAS #
50-00-0
Form
Liquid
State
Solids containing varying amounts of formaldehyde, probably as paraformaldehyde (polymers of formula HO(CH2O)xH where x averages about 30). A hazard to the environment. Immediate steps should be taken
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.
Denaturant
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
Discovered by German chemist August Wilhelm von Hofmann in 1859 and used as a preservative in cosmetics and embalming fluids from the late 19th century onward. It became a common cosmetic preservative despite later health concerns, particularly in nail products.
EWG
10
CIR
Safe as used
Pregnancy
No
Restricted By
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Concentration Guide
5%
0%7%
Reg. Limit
EU regulatory limit: 5%. 5 % (as formaldehyde). Protect cuticles with grease or oil Contains formaldehyde (3) Source: EU Cosmetics Regulation (EC) 1223/2009, Annex III (Restricted Substances), Entry 13.
Regulatory Agencies
🧂Conflict of interest.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
No
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory0 listings
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026 · 🧪 = conflict
Data: PubChem · CosIng · EWG · CIR