Glossary
A synthetic humectant and solvent widely used in skincare, cosmetics, food, and pharmaceutical products. Propylene glycol attracts water, enhances ingredient penetration, and serves as a vehicle for other active ingredients. It is FDA-approved as GRAS but is a common contact allergen.
Propylene glycol (PG) is one of the most ubiquitous ingredients in consumer products. It appears in moisturizers, serums, shampoos, deodorants, medications, food products, fog machines, and antifreeze (this last association unfairly damages its reputation, since the PG used in food and cosmetics is a different grade from the industrial product). Its versatility comes from its dual function as a humectant (attracting water to the skin) and a solvent (dissolving and carrying other ingredients into the skin).
As a humectant, propylene glycol draws water from the environment and from deeper skin layers to the surface, providing hydration. As a penetration enhancer, it disrupts the lipid structure of the stratum corneum slightly, allowing other active ingredients to absorb more effectively. This dual function makes it attractive for formulators who want both hydration and enhanced delivery of active ingredients.
Propylene glycol is FDA-classified as Generally Recognized as Safe (GRAS) and is approved for use in food, pharmaceuticals, and cosmetics at concentrations up to 50%. However, it is also one of the more common contact allergens in skincare, affecting approximately 2 to 5% of dermatitis patients in patch testing studies. People with eczema or compromised skin barriers are more susceptible to PG sensitivity.
For consumers who prefer to avoid propylene glycol, natural humectant alternatives include glycerin (plant-derived), honey (natural humectant with additional antimicrobial benefits), hyaluronic acid, and aloe vera. Our products use natural humectant properties inherent in our ingredients rather than synthetic humectants like propylene glycol.
No. Propylene glycol and ethylene glycol are different chemicals. Ethylene glycol is the toxic antifreeze ingredient. Propylene glycol is FDA-approved, non-toxic, and used safely in food, medicine, and cosmetics. The confusion arises because PG is sometimes used as a safer, non-toxic alternative in antifreeze formulations.
PG allergy is confirmed through dermatological patch testing. Symptoms of PG contact dermatitis include redness, itching, and eczema-like reactions in areas where PG-containing products are applied. If you suspect PG sensitivity, try eliminating PG-containing products and observe whether symptoms resolve.
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