Common Name(s): Propylene glycol,1,2-propanediol humectant,co-solvent penetration enhancer
CAS Number: N/a
DESCRIPTION
What It Does: Provides skin hydration through hydroxyl group water-binding, dissolves both hydrophilic and moderately lipophilic actives for incorporation into formulations, and mildly enhances penetration of co-applied actives by sc lipid disruption.
Why It's Used: Pg's dual polarity (two oh groups + short c3 chain) provides the broadest active solubility range of any common humectant-solvent โ dissolving ingredients that neither water nor conventional oils can dissolve individually.
How It Works: Two oh groups (pka >>14) form h-bonds with water (humectancy) and sc intercellular lipids (penetration enhancement). pg's logp 0.14 allows sc lipid intercalation that transiently disrupts ordered lamellar packing, increasing diffusion coefficient of co-applied actives by 2โ5ร. at high concentrations (>50%), direct antimicrobial activity from membrane disruption.
Typically Found In: All cosmetics,active delivery systems
TECHNICAL DETAILS
Primary Category: Functional ingredient โ humectant
Secondary Functions: Tewl reduction,skin plumping
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 1%โ30%
SOURCING & ETHICS
Vegan Status: Yes
Halal Status: Yes
Source Notes: Synthetic or naturally derived. excellent aqueous solubility.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Non-irritating; suitable for all skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Excellent safety profile. ewg score: 1.
Works Well With: Ceramides,emollients,occlusives,glycerin,hyaluronic acid
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Pg sensitisation risk at high concentrations: contact sensitisation is documented at >20% concentration in patch test studies โ modern formulations typically limit pg to <10% and use butylene glycol or propanediol as alternatives where sensitisation is a concern.
Last Verified: Cosing database,propylene glycol humectant penetration review
Primary Sources: 2026-03-12
