http://www.paulaschoice.com/cosmetic-ingredient-dictionary/definition/propanediol
"A glycol that can enhance the absorption of ingredients (such as salicylic acid) into the skin. Propanediol can be derived naturally (from corn) or synthetically. It has hydrating properties that may leave a smooth, dewy finish. Propanediol is a well-tolerated ingredient, not likely to cause sensitivity."
【Propanediol】
Rating: GOOD
Benefits: Hydration
Categories: Solvent, Texture Enhancer
Propanediol (also known as 1,3-propanediol) is a glycol that can increase the absorption of ingredients (such as salicylic acid) to improve their effectiveness. Additionally, it offers moisturizing properties that can result in a smooth, dewy finish as the formula sets. Propanediol is a considered a safe, well-tolerated ingredient, not likely to cause sensitivity.
Propanediol is a versatile ingredient with additional properties that make it a favorable choice in skin care products, including its ability to boost the effectiveness of a preservative system within a formula. It can also serve as a solvent in a blend of ingredients.
Propanediol can be derived naturally from corn or created synthetically. It is a colorless to pale yellow, viscous (somewhat sticky) liquid and is chemically similar to 1,2-propanediol (propylene glycol).
In June 2018 the Cosmetic Ingredient Review Board reevaluated propanediol’s use in personal care products and concluded that it is safe. For leave-on products it was recorded in up to a 39.9% concentration (for a deodorant) - skin care products generally contain lower amounts than that.
https://www.paulaschoice.com/ingredient-dictionary/ingredient-propanediol.html