The Brij O range are primary O/W emulsifiers, particularly suited to emulsifying unsaturated fatty acids. Suitable for the formulation of microemulsion gels as primary emulsifiers or as co-emulsifiers paired with Crodafos phosphate esters. They are solubilising, dispersing, spreading, wetting and gelling agents. When used as a co-emulsifier, Brij O5 tends to lower the temperature at which a system gels, resulting in a clear gel with a more manageable set point. Recommended topical usage levels of 0.5-10%.