Solvent

Poly 1,2-Butanediol-6 Propylene Glycol

INCI: POLY 1,2-BUTANEDIOL-6 PROPYLENE GLYCOL

Reviewed by Kate · Last updated 2 Jun 2026

A solvent that helps dissolve and deliver other skincare actives effectively

Best For Skin Types

All

Usage Frequency

As directed by product instructions

What Is Poly 1,2-Butanediol-6 Propylene Glycol?

Poly 1,2-butanediol-6 propylene glycol is a synthetic polymer that functions primarily as a solvent in skincare formulations. It is composed of repeating units of butanediol and propylene glycol, both humectant compounds that have been used safely in cosmetics for decades. This ingredient helps dissolve other actives and ingredients that would otherwise be poorly soluble, enabling formulators to create stable, effective products.

By improving the solubility of active ingredients, this polymer allows formulators to achieve higher concentrations of beneficial compounds in a single product without compromising stability or texture. It is typically used in leave-on formulations where its solvent properties support ingredient efficacy.

How It Works

This ingredient works by dissolving poorly soluble compounds through its chemical structure, which contains both hydrophobic (water-repelling) and hydrophilic (water-attracting) regions. This dual nature allows it to interact with a wide range of active ingredients, breaking them down into smaller, more bioavailable forms that the skin can better utilise.

When incorporated into a formulation, it maintains the dissolved state of these actives, preventing them from separating or crystallising out over the product's shelf life. This ensures that the active ingredients remain stable and effective throughout use.

Clinical Evidence & References

Research exploring propylene glycol and related polymers suggests they play an important role in enhancing the delivery of poorly soluble active ingredients, including pharmaceutical compounds. Studies examining drug delivery systems have shown that polymers in this class can improve permeation and bioavailability of actives across biological membranes.

However, specific clinical evidence for this particular polymer formulation's direct skin benefits is limited in published literature. Its primary value lies in its functional role as a solvent rather than as an active ingredient in its own right. The skincare benefits depend largely on the actives it helps deliver.

How to Use

This ingredient is typically used as a supporting component rather than a standalone active, so its presence alone is not the key consideration. Look at the complete formulation and the active ingredients it is helping to solubilise. Use products containing this ingredient as directed by the brand, typically as part of your regular skincare routine.

Safety & Precautions

Generally well-tolerated in skincare formulations. As with all cosmetic ingredients, discontinue use if irritation occurs.

Frequently Asked Questions

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