Body & Beauty / Compounds / Propylene glycol

Propylene glycol on your skin: a safety profile

Low risk

(People-specific data is limited; this page draws from human adult context.) Propylene glycol is one of the most widely evaluated and generally recognized as safe food and pharmaceutical additives for humans. The Acceptable Daily Intake established by JECFA is 25 mg/kg body weight — for a 70-kg adult, this represents 1,750 mg/day, far exceeding typical dietary exposure from food uses as a humectant, carrier, and solvent. PG is extensively used in food products, pharmaceuticals (oral, injectable, and topical), cosmetics, electronic cigarette liquids, and personal care products. In humans, PG is rapidly metabolized by alcohol dehydrogenase to lactate and pyruvate — normal physiological metabolites — without production of the toxic metabolites that make ethylene glycol dangerous. High-dose intravenous PG (used as a pharmaceutical vehicle at concentrations not achieved through food or cosmetic use) can cause lactic acidosis in infants and patients with renal/hepatic impairment. Rare allergic contact sensitization to PG occurs, but systemic toxicity from food and cosmetic exposures in healthy adults is not documented at real-world doses.

What is propylene glycol?

The IUPAC name is propane-1,2-diol.

Also known as: propane-1,2-diol, 1,2-propanediol, 1,2-Propylene glycol, 1,2-dihydroxypropane.

IUPAC name
propane-1,2-diol
CAS number
57-55-6
Molecular formula
C3H8O2
Molecular weight
76.09 g/mol
SMILES
CC(CO)O
PubChem CID
1030

Risk for people

Low risk

Propylene glycol is one of the most widely evaluated and generally recognized as safe food and pharmaceutical additives for humans. The Acceptable Daily Intake established by JECFA is 25 mg/kg body weight — for a 70-kg adult, this represents 1,750 mg/day, far exceeding typical dietary exposure from food uses as a humectant, carrier, and solvent. PG is extensively used in food products, pharmaceuticals (oral, injectable, and topical), cosmetics, electronic cigarette liquids, and personal care products. In humans, PG is rapidly metabolized by alcohol dehydrogenase to lactate and pyruvate — normal physiological metabolites — without production of the toxic metabolites that make ethylene glycol dangerous. High-dose intravenous PG (used as a pharmaceutical vehicle at concentrations not achieved through food or cosmetic use) can cause lactic acidosis in infants and patients with renal/hepatic impairment. Rare allergic contact sensitization to PG occurs, but systemic toxicity from food and cosmetic exposures in healthy adults is not documented at real-world doses.

Regulatory consensus

3 regulatory and scientific bodies have classified Propylene glycol. The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 9 positive / 4 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 9 positive / 4 negative reports)
EPA CTX / Skin-Eye—skin irritation: in vivo: Studies Indicate No Significant Irritation (score: low)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter propylene glycol

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Fragrance — perfume, cologne, scented personal care products, household fragrance products, candles
    Identified in Fragrance Ingredient Safety Priority Research database (2,325 ingredients)

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Propylene glycol:

  • Physical/mechanical pest control (IPM)
    Trade-offs: More labor-intensive. May not be sufficient for severe infestations.
    Relative cost: 1.2-2×

Frequently asked questions

What products contain propylene glycol?

Propylene glycol appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); perfume (Fragrance).

Why do regulators disagree about propylene glycol?

Propylene glycol has been classified by 3 agencies including EPA CTX / Genetox, EPA CTX / Genetox, EPA CTX / Skin-Eye, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Propylene glycol in the body app

Look up products containing propylene glycol, compare to alternatives, and explore the full data record.

Open in body View raw API data

Sources (2)
  1. US FDA: Propylene Glycol in Animal Food — Final Rule Prohibiting Use in Cat Food (21 CFR 582.4666) and GRAS Status for Dog Food (1996) — regulatory
  2. ASPCA Animal Poison Control Center: Propylene Glycol — Heinz Body Anemia Risk in Cats and Species Differences in Erythrocyte Sensitivity (2022) — veterinary

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →