Propylene glycol (PG) – Humectant Humectant

What is Propylene glycol?

Propylene glycol is a clear, odorless and tasteless liquid that belongs to the glycol family. It is soluble in both water and alcohol. It is versatile and widely used in cosmetics, pharmaceuticals and foods.

Use in DIY Cosmetics

In homemade cosmetics, propylene glycol is widely used as a humectant, solvent, texture enhancer and as a carrier for active ingredients such as fragrances or extracts. It helps keep skin hydrated by attracting and retaining water, and ensures that products such as serums, creams and gels remain smooth and stable. It is also used in sprays and toners to distribute active ingredients evenly.

Recommended amounts in cosmetics

Propylene glycol is usually used in cocentrations of 1% to 10%, depending on the type of product. In serums or gels, it is often around 2-5%, while lower doses are common in toners and sprays. At higher concentrations, it can irritate the skin, especially in sensitive skin types.

Use in Soap

In soap formulations, particularly transparent glycerin soap (Melt & Pour), propylene glycol is used to retain moisture, improve transparency and soften texture. It also helps dissolve fragrances and dyes and contributes to a smooth texture.

Quantity in soap

In transparent soap formulations, 5% to 15% propylene glycol is often added, depending on the recipe. Too much can result in a sticky or too soft soap, especially in humid environments.

Safety and origin

Propylene glycol is considered safe for use in cosmetics if used in low concentrations. It is non-comedogenic and generally non-irritating, although some people may react sensitively with prolonged or frequent use.

Propylene glycol is a useful ingredient in DIY cosmetics and soaps thanks to its moisturizing, stabilizing and soluble properties. Use it in concentrations from 1% to 10% in cosmetics and up to 15% in soap.

Technical data

INCI: Methylethylglycol, 1,2-propanediol
Empirical formula: C₃H₈O₂
Molar mass (M): 76.10 g/mol
Density (D): 1.04 g/cm³
Boiling point (bp): 188 °C
Flash point (flp): 99 °C
Melting point (mp): -59 °C
WGK 1
CAS number: 57-55-6
EC number: 200-338-0