Cosmetic surfactants are the most versatile and important ingredients in cosmetic formulations. Unfortunately, there are not many surfactants that naturally occur so trying to make natural formulas with surfactants is a real challenge. In this post we’ll look at your options for natural surfactants in cosmetic products.
Levels of natural
Before we can review the surfactants it is helpful to first discuss what is meant by the term “natural.” Since there is no Shampoo bush or Skin Lotion tree by some measures there are NO natural cosmetics. But as we saw you can define natural cosmetics following specific standards. In this discussion we’ll use a three level classification system of natural cosmetics. These include
- True natural - Ingredient is isolated from a plant, chemically purified, but otherwise unchanged
- Acceptable natural - Ingredient conforms to some acceptable natural standard which allows some chemical modification
- Greenwashing natural - Ingredient is naturally derived but requires significant chemical synthesis to produce. Also, it is not normally used so looks more natural on the label.
Types of surfactants
As we saw in a previous post on what surfactants do, they have many applications and different surfactants are used for different formulating purposes. This includes cleansing, emulsifying, foaming, conditioning and more. The natural surfactants available are not nearly as versatile as synthetic surfactants so you need different kinds for different applications.
Natural cleansing surfactants
True natural - There aren’t many natural surfactants that are adequate for use as a cleansing surfactant. The only one that comes close are Saponins. These are glycoside compounds which have the ability to form foam when put in a water solution. They are found in plants like Yucca (Yucca schidigera), Soapwort (Saponaria officinalis), Soapbark (Quillaia saponaria) and Soapnut (Sapindus spp). The majority of commercial saponins are derived from Quillaja bark or soapnut and obtained through water and alcohol extraction. Unfortunately, formulators who have reported using saponins for cleansing products have been disappointed.
Acceptable natural - If you are formulating to the USDA natural organic standards there are no natural surfactants you can use. Some companies like Nourish Organic use a chemical trick where they create a surfactant in-situ by including natural ingredients that chemically react to make a soap. In the formula linked the Coconut Oil will saponify with the Potassium Hydroxide. But liquid soaps like these are harsh on skin and most consumers don’t like how they feel.
If you are following the COSMOS standard there are a number of surfactants that are acceptable. The ones that are typically used for cleansing products are
- Lauryl Glucoside
- Decyl Glucoside
- Caprylyl/Decyl Glucoside
- Coco Glucoside
- Cocamidopropyl Betaine
Interestingly, the COSMOS standard even allows for the use of Sodium Lauryl Sulfate since it can be derived from natural sources.
Greenwashing natural - Since many natural consumers are tuned in to chemical scaremongers the use of cleansing surfactants like SLS is probably not a good idea. Sulfates have a bad reputation on the Internet and even though they are considered natural by the COSMOS standard, consumers wouldn’t accept that. However, some companies simply replace scary sounding ingredients like Sulfates with other synthetic anionic surfactants. These include ingredients like Taurates, Sarcosinates, and Glutamates. As long as you avoid sulfates, you can pretty much use any type of naturally derived synthetic surfactant and call yourself natural.
Finding good performing emulsifiers for natural cosmetics is also a challenge. There aren’t many and your choice is mostly dependent on the composition of your oil phase.
True natural - There are some natural ingredients that have been used to create emulsions. These include things like Lecithin, Beeswax, and Candelilla wax. Of these, only Lecithin would be considered a true emulsifier. You can make emulsions using waxes but the chemistry is a bit more complicated. Other emulsifiers that are natural are ingredients derived from biotechnology and fermentation reactions. These would be acylpolyols, acylpeptides, and glycolipids. The challenge of using these is that they are expensive.
Acceptable Natural - It’s rather surprising how many synthetic emulsifiers are acceptable by the COSMOS standard. Useful traditional standbys like Glyceryl Stearate and Steric Acid are both acceptable. Also, materials like Cetyl Alcohol, Stearyl Alcohol, and Polyglycerols can also be used. For thickening and stabilization you can use Xanthan Gum. If you’re following the COSMOS standard you can make something that looks and behaves very much like a standard emulsion.
Greenwashing Natural - As far as emulsions go, it would be hard to show a difference between a greenwashed formula and one that uses acceptable natural standards. The main difference would be the use of ethoxylated surfactants and silicones like Dimethicone copolyol.
Natural surfactants in the future
Finding natural surfactants to use in natural cosmetic formulations continues to be a challenge. The choices are limited and the resulting product aesthetics are not nearly as good as what synthetic formulations have to offer. But research continues particularly in the area of the production of bio-fermentation of surfactants. If researchers could develop ingredients from microbes that demonstrate effectiveness at a higher yield there may yet be a truly natural surfactant that replaces most of the pseudo-natural surfactants being offered today.