Water Phase: Definition and Role in Cosmetic Formulation

What Is the Water Phase?

The water phase is the part of a cosmetic formulation in which water is the main continuous or dissolving medium. It typically contains ingredients that are soluble or dispersible in water.

Depending on the formulation, the water phase may contain:

• Water
• Humectants such as glycerin
• Water-soluble active ingredients
• Preservatives
• Chelating agents
• Water-soluble polymers
• Other water-soluble ingredients

Water Phase in Emulsions

In an emulsion, the water phase can form either the continuous phase or the dispersed phase.

In an oil-in-water (O/W) emulsion, water is the continuous phase and oil droplets are dispersed throughout it.

In a water-in-oil (W/O) emulsion, water is dispersed as droplets within a continuous oil phase.

The composition of the water phase therefore has an important influence on the texture, stability and performance of the finished product.

Water Phase in Cosmetic Manufacturing

During formulation development and manufacturing, water-phase ingredients are often combined and processed separately before being incorporated with the oil phase or other components.

The temperature, order of addition, mixing conditions and solubility of the ingredients need to be considered to obtain a stable and uniform formulation.