Propylene Glycol
Dihydric alcohol that functions as a humectant and penetration enhancer. At high concentrations, it can irritate sensitive skin.
Evidence by route
Topical application
Primary function is solvent and penetration enhancer. CIR deemed safe at concentrations up to 50%. Contact dermatitis reported in 1–3% of dermatology clinic patients on patch testing.
- Lessmann H et al. Contact Dermatitis. 2005;53(3):150-156. PMID 16283903
How to read tiers A–F
- DNo data, or very weak or conflicting data
Tolerability and safety
- Irritation potential
- Medium
- Allergen risk
- Moderate
- Pregnancy
- Safe
- Suitable for
- Normal, Oily, Combination
- Use with caution
- Sensitive, Dry
For sensitive skin
Sensitive skin may experience irritation at concentrations above 10%. Causes contact allergy in 1–3% of individuals.
About this ingredient
Propylene Glycol (1,2-Propanediol, PG) is a dihydric alcohol. One of the older and widely used humectants and solvents in cosmetics, pharmaceuticals, and food (E1520). Where applied. Serums, toners, creams, shampoos, gels (1-30%). In topical pharmaceuticals (ointments, scalp lotions, solutions) – up to 50%. Mechanism. Humectant: retains water in the stratum corneum. Penetration booster: helps water-soluble actives (e.g., hydrocortisone in pharmacology) cross the epidermis. Safety – controversy. CIR confirmed safety at cosmetic concentrations. However, propylene glycol is a known contact allergen: contact dermatitis in 1.5-3.8% of the general population and up to 5% of eczema patients (Schnuch 2013). The NACDG (American Contact Dermatitis Society) named propylene glycol "allergen of the year 2018". At concentrations above 5-10% can irritate dry and sensitive skin. Alternative. Since the 2010s, high-quality cosmetics have gradually replaced it with propanediol (1,3-Propanediol) – a structural isomer with better tolerance. Pregnancy and lactation – safe at cosmetic concentrations. Transdermal systemic absorption is low. EU and FDA impose no restrictions.
Frequently asked questions
Is Propylene Glycol safe during pregnancy?
Propylene Glycol is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Propylene Glycol for?
Propylene Glycol suits: normal, oily, combination. Use with caution in: sensitive, dry.
Can Propylene Glycol irritate the skin?
Propylene Glycol has moderate irritation potential. Sensitive skin may show a transient reaction that usually settles with adaptation.
What is Propylene Glycol and what does it do in cosmetics?
Dihydric alcohol that functions as a humectant and penetration enhancer.
What's the INCI name for Propylene Glycol?
The INCI name is Propylene Glycol. It may also appear as: 1,2-Propanediol.
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