Propanediol: A Modern Alternative to Propylene Glycol in Cosmetic Formulas

Nicole Regan Feb 19, 2026

Propylene Glycol is a widely used cosmetic ingredient valued for its humectant and solvent performance in everything from cleansers to creams. At the same time, many brands are looking for glycol options that better align with naturally derived positioning or “propylene glycol–free” ingredient philosophies.

One common option is Propanediol (often 1,3-propanediol)—often available from bio-based supply chains (for example, corn sugar–derived via fermentation, depending on the supplier and grade)) and used in personal care as a multi-functional support ingredient. Shape

Why brands consider an alternative

Ingredient decisions aren’t only technical—they’re commercial. Both indie and established brands see more end customers researching INCI lists and forming opinions from a mix of scientific and nonscientific sources. As consumer scrutiny increases, some brands choose to avoid certain ingredient names on labels, even when the ingredient is permitted and broadly used. For sensitive skin positioning specifically, propylene glycol is documented as a potential irritant or sensitizer in a small subset of individuals, even though it is considered safe for use in cosmetics when formulated with correctly.

For a brand owner, this often translates into a simple brief: “Can you build this formula without propylene glycol?”—even when the driver is perception rather than a regulatory requirement. Providing propanediol as an option lets you respond to those requests without changing the core product experience or making negative claims about propylene glycol itself.

Propylene Glycol vs. Propanediol: What’s actually different?

Although Propylene Glycol and Propanediol share the same chemical formula (C₃H₈O₂), they differ in molecular structure and therefore have different identifiers and regulatory listings (e.g., distinct INCI names and CAS numbers).

Propylene Glycol

Commonly produced from petrochemical feedstocks (industry standard supply chain)
Well‑established use history in cosmetics; however, patch test data and case reports show irritation or allergy in a subset of users.
SDS references typically list a closed‑cup flash point a little above 100 °C, depending on grade and method

Propanediol (1,3-Propanediol)

Often available as bio-based, renewable or plant-based feedstocks (commonly corn sugar–derived)
Frequently used as a humectant/solvent in naturally positioned formulations
Some suppliers report favorable sustainability metrics vs. propylene glycol (example: lower fossil-based carbon inputs compared with conventional glycols). Environmental claims should be confirmed against the specific supplier’s documentation you are using

Practical formulation notes when switching

In many formulas, propanediol can be evaluated as a 1:1 replacement for propylene glycol, but performance depends on the overall system (surfactants, polymers, preservatives, electrolyte load, etc.).

If you encounter haze or solubility changes:

Add propanediol into the water phase first
Consider a modest temperature increase during processing (as appropriate for the formula)
Re-check clarity after cool-down and 24–48 hours

Formulation Tip: Typical use range targets 3–5% in emulsions, and a bit higher in toners. Actual optimal level may vary by formula, supplier grade, and desired sensorial profile. Always make sure you test your preservative performance when changing anything in a formula. Challenge or PET/compatibility testing as appropriate.