Dipropylene glycol, 1 l

Dipropylene glycol (dipropylene glycol) retains moisture in a formulation and at the same time dissolves components that are otherwise difficult to dissolve in water on their own. In cosmetics it works as a humectant, in fragrance blending as a carrier for perfume compositions and fragrance oils. In a formulation it therefore serves three roles at once: binding water, diluting and carrying active and fragrance components.

It suits manufacturers thanks to its low volatility, nearly neutral odour and miscibility with both water and alcohol. Dosage ranges from 1% to 50%, making it useful as a minor addition to the water phase as well as the main diluent component for fragrance oils in diffusers.

Key properties

• Stable moisture in the product – maintains the water content of the preparation at a consistent level regardless of temperature and humidity fluctuations. Creams, lotions and tonics dry out less and support skin hydration.
• Solvent and carrier – dissolves perfume compositions, fragrance oils and active ingredients that would otherwise be difficult to incorporate into a water base. It serves the same purpose in deodorants, antiperspirants and lip products.
• Low volatility and virtually no odour – does not mask the scent of the finished product and evaporates more slowly than ethylene glycol.
• Lower hygroscopicity – attracts less moisture from the air compared to diethylene glycol and ethylene glycol.
• No CLP classification – the substance is not classified as hazardous, is readily biodegradable (OECD 301) and is suitable for vegan cosmetics.

Use in formulation

It is added to the water phase: in emulsions before emulsification, in cold-process manufacturing directly into the water part of the formula. It tolerates processing at temperatures up to 80 °C, making it suitable for hot-process creams as well as cold-mixed products. The recommended pH range for the formulation is 5.0 – 7.5.

The recommended dosage is 1 – 50%. The lower end of the range corresponds to the role of humectant in creams, tonics and lotions. The upper end is reserved for diluting fragrance compositions for diffusers and fragrance sprays, not for facial emulsions.

In W/O (water-in-oil) emulsions it also acts as a solubiliser. It is compatible with common cosmetic raw materials without restriction and, being colourless itself, does not affect the shade of the product.

Suitable for products such as

• Facial care – tonics, serums, creams and lotions, where it retains moisture and facilitates the incorporation of active ingredients.
• Diffusers and aromatherapy – diluent for fragrance oils in reed diffusers and fragrance sprays.
• Deodorants and antiperspirants – carrier of active ingredients and fragrances in sticks and roll-on products.
• Shower and bath products – water phase supplement in shower gels and foaming bath products.
• Soaps – helps incorporate fragrance components into the mass.
• Lip care and decorative cosmetics – solvent and humectant in balms, glosses and pigmented products.

Good to know

Dipropylene glycol is a synthetic raw material. Chemically, it is produced by condensation of 1,2-propylene glycol and is supplied as a mixture of isomers. It is therefore not suitable for formulations intended to meet natural cosmetics requirements.

The raw material is free of preservatives, parabens, phthalates and palm oil and contains none of the fragrance allergens listed in Annex III of the cosmetics regulation. It holds Kosher and Nordic Swan Approved certifications, opening it up to formulations with eco-labelling requirements.

Frequently asked questions