murphyPropylene Glycol
AKA: 1, 2-propanediol, Propane-1, 2-diol, 57-55-6, 2-Propylene glycol, 2-dihydroxypropane, 2-Hydroxypropanol, Isopropylene glycol, Dowfrost, Sirlene
Synthetic
Humectant
Solvent
Skin Conditioner
Not Clean
OriginDerived from propylene, a byproduct of petroleum refining or natural gas processing.
Synthesized through hydration of propylene oxide via catalytic reaction with water.
Propylene glycol (1,2-propanediol) is an organic compound (a diol alcohol), usually a tasteless, odorless, and colorless clear oily liquid that is hygroscopic and miscible with water, acetone, and chloroform. It is manufactured by the hydration of propylene oxide. Propylene glycol is used as a solvent for intravenous, oral, and topical pharmaceutical preparations It is generally considered safe. However in large doses it can be toxic, especially if given over a short period of time. Intravenous lorazepam contains the largest amount of propylene glycol of commonly used drugs. In adults with normal liver and kidney function, the terminal half-life of propylene glycol ranges from 1.4 to 3.3 hours. Propylene glycol is metabolized by the liver to form lactate, acetate, and pyruvate. The nonmetabolized drug is excreted in the urine mainly as the glucuronide conjugate, approximately 12 to 45 percent is excreted unchanged in urine. Renal clearance decreases as the dose administered increases (
Solubility greater than or equal to 100 mg/mL at 70 °F (NTP, 1992)
Formula
C3H8O2
Mol. Weight
76.09
CAS #
57-55-6
Form
Powder
State
Thick odorless colorless liquid. Mixes with water. (USCG, 1999)
Skin Types
●all-skin-types
Best For
Dryness
Pregnancy & Breastfeeding Safe
Yes
Functions
Humectant
A moisture magnet. Pulls water from the air and deeper skin layers up to the surface to keep skin plump and hydrated.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Solvent
Dissolves other ingredients so they distribute evenly in the formula. Often the invisible "base" everything else is mixed into.
Viscosity Controlling
Locks In Moisture
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
3
CIR
Safe as used
Pregnancy
Yes
Restricted By
CIR Safety Findings
Not Phototoxic
Human test found no phototoxicity in the CIR safety assessment (CIR 560)
Mixed Eye Irritation Results
3 studies / 1 irritating / 1 mixed / 1 not irritating / reactions slight to moderate (CIR 77 and 560)
Mixed Skin Irritation Results
28 studies / 11 irritating / 7 mixed / 10 not irritating / reactions minimal to moderate / plus 5 case reports (CIR 77 and 560)
Mixed Sensitization Results
18 studies / 2 mixed / 16 not sensitizing / plus 14 case reports (CIR 77 and 560)
Dermal Absorption 57.1%
excised female hairless mouse skin / in vitro / [14C]PG in ternary cosolvent containing 10 mol% oleic acid and 6 mol% dimethyl isosorbide in 84% PG / 24 hours (CIR 560)
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR