Introduction

W/O (water-in-oil) emulsions are becoming more and more preferred in the personal care space, particularly regarding color cosmetics and sun care.

In color cosmetics, W/O foundations offer better water resistance, long-wear, and high coverage – all the performance qualities a consumer desires – compared to O/W (oil-in-water) formulations. And though W/Si (water-in-silicone) formulations may offer great performance and texture, they do not qualify as natural makeup, making them a less desirable option among younger shoppers.

When it comes to sun care, consumers are moving towards mineral options. For example, sunscreen launches containing zinc oxide increased by 45% from 2014-15 to 2018-19 in North America [1]. Zinc oxide is easier to formulate in a W/O than an O/W system. In fact, most inorganic sunscreens are either anhydrous or W/O formulations.

However, formulating can be easier said than done, as there are many challenges that come with making a stable W/O product. W/O systems are more sensitive to other ingredients and require more energy in their processing to ensure stability. There are two key factors to consider when it comes to W/O formulation: oil polarity and electrolyte addition, which may not have any influence or not even be necessary for O/W formulations.