Emulsifiers in Cosmetics - What You Should Know About Combining Water and Oils

Have you ever wondered why a cream has such a smooth, uniform texture even though it contains both water and oils? The answer lies in emulsifiers - the ingredients that make it possible to combine two phases that normally don't mix. Without them, any cream would separate into layers within a few minutes.

What are emulsifiers and why are they essential?

Emulsifiers are surface-active substances that have a hydrophilic (water-loving) part and a lipophilic (fat-loving) part. Thanks to this dual nature, they can position themselves at the boundary between phases and keep tiny droplets of one phase dispersed within the other. This is exactly what creates the stable emulsion we know as a cream, lotion or body milk.

It's worth understanding that emulsifiers aren't an optional extra - they're a fundamental component of any multi-phase product. If you want to get better at understanding the ingredients in your cosmetics, start with our guide to reading the INCI list.

O/W vs W/O emulsions - what's the difference?

Emulsions fall into two basic types depending on which phase forms the surrounding medium:

O/W emulsions (oil in water)

In O/W emulsions, tiny droplets of oil are dispersed throughout the water phase. This is the most common type of emulsion in everyday skincare. O/W creams are lightweight, absorb quickly and don't leave a greasy film on the skin. They work perfectly as a makeup base and for combination or oily skin.

W/O emulsions (water in oil)

In W/O emulsions, it's the water droplets that are dispersed throughout the oil phase. These products are considerably richer, more occlusive and better at protecting the skin from water loss. They're a great fit for winter creams, products for very dry skin and sun care cosmetics, since they're more resistant to being washed off by water.

The type of emulsion has a direct impact on how a product feels. That's why two creams with seemingly similar ingredient lists can apply completely differently - it all comes down to the type of emulsion and the choice of emulsifier.

The controversy around PEGs

PEGs (polyethylene glycols) are among the most widely used emulsifiers in cosmetics. You'll find them on INCI lists as PEG-20, PEG-40 Hydrogenated Castor Oil, PEG-100 Stearate and many others. The number in the name indicates the degree of polymerisation - the higher it is, the larger the molecule.

The main criticism levelled at PEGs concerns potential contamination with 1,4-dioxane and ethylene oxide - substances that can form as by-products during the ethoxylation process. However, modern purification methods effectively eliminate these contaminants to levels well below safety thresholds.

The Scientific Committee on Consumer Safety (SCCS) at the European Commission has repeatedly assessed PEGs as safe for cosmetic use. It pays to approach this topic rationally - take a look at our comparison of natural and synthetic ingredients to better understand these debates.

Fatty alcohols - emulsifiers that aren't what you think

One of the most common misconceptions in the world of cosmetics is confusing fatty alcohols with ethyl alcohol. Cetyl Alcohol, Cetearyl Alcohol and Stearyl Alcohol are long-chain fatty alcohols that act as emulsifiers and co-emulsifiers. They don't dry out the skin - quite the opposite, they have an emollient, smoothing effect.

Fatty alcohols stabilise emulsions, improve a product's texture and help create a pleasant, creamy consistency. They're widely used in both conventional and natural cosmetics. If you'd like to learn more about the different types of ingredients, visit our ingredient database.

Modern alternatives - next-generation emulsifiers

The cosmetics industry is constantly developing new types of emulsifiers. Among the popular alternatives to classic PEGs, you'll find:

• Olivem 1000 (Cetearyl Olivate + Sorbitan Olivate) - an emulsifier derived from olive oil that creates emulsions with a structure similar to the skin's own lipids
• Montanov 68 (Cetearyl Alcohol + Cetearyl Glucoside) - a sugar-based emulsifier that forms stable lamellar emulsions
• Sucragel - sucrose-based emulsifiers that are gentle and well tolerated

These modern emulsifiers often create emulsions with a lamellar structure that mimics the natural makeup of the skin's lipid barrier. As a result, the products can do a better job of supporting the skin's protective function.

What to look out for when choosing products?

The choice of emulsifier in a cosmetic is above all a matter of formulation - a good cosmetic chemist will select an emulsifier suited to the particular type of product and target audience. As a consumer, it's worth knowing that:

• The presence of PEGs doesn't automatically mean a poor product
• Fatty alcohols on the INCI list are ingredients that benefit the skin
• The type of emulsion (O/W vs W/O) affects how the product feels on application
• Natural emulsifiers aren't by definition better than synthetic ones

Want to find out which emulsifiers are in your favourite cream? Search for the product in our database and discover the full ingredient list with a rating for every component.