Using pre-blended emulsifiers in cosmetic formulas
Pre-blended emulsifiers can be a great and easy addition when creating cream and lotion formulas, but what exactly are they, when should they be used, and how much is typically added to a cosmetic formula?
How emulsions are usually formed
All creams and lotions are emulsions: a mixture of two normally immiscible substances (such as oil and water) to create a milky looking end product. The most common type of cosmetic emulsion is the oil in water emulsion (often written more simply as o/w). An o/w emulsion has an internal oil phase dispersed as droplets within a greater external water phase.
To create an o/w emulsion, a combination of emulsifiers is typically used to get the best long term stability or shelf life. This is usually a mixture of:
- an anionic emulsifier (negatively charged emulsifier, the most common one you would be likely to see on a label is stearic acid); and
- non-ionic emulsifiers, typically a blend of two individual non-ionic waxy materials, to bring extra stability and viscosity to the finished product (non-ionic means no charge; perhaps the most commonly used blend you would see is cetearyl alcohol and ceteareth-20);
- an additional non-ionic emulsifier may be used to build viscosity and reduce white rub in time in extremely viscous products like night creams or body butters – this type of material would have a preference for the oil phase (chemically described as having a low HLB) and would also be non-ionic (a common example you may be familiar with is glyceryl stearate).
Choosing an individual anionic emulsifier and pre-blended non-ionic emulsifier blend as separate ingredients has, for many years, been the preferred option of Cosmetic Chemists because it allows them to pick and choose materials to suit the needs of a formula: the required natural content, final viscosity, skin feel, rub in time, and stabilizing needs based on oil content.
You’ll find guidance on how to choose different emulsifiers, and how much to use, in the different types of emulsion formulas provided in all three of the create cosmetic formulas programs (organic, general hair and skin, and make-up).
What are pre-blended emulsifiers?
In recent years, we have seen an influx of fully pre-blended emulsifiers enter the market: these are materials where the product comes as a pre-blend of the anionic emulsifier, along with at least two, if not three, non-ionic materials. One example is Phytocream 2000, which is a pre-blended emulsifier containing Potassium Palmitoyl Hydrolyzed Wheat Protein (anionic), Glyceryl Stearate (non-ionic) and Cetearyl Alcohol (non-ionic). This pre-blended emulsifier is supplied as one material, already mixed together, rather than as individual ingredients. The input of a pre-blended material is commonly similar to the total amount of emulsifiers you would use when using individual materials, added together.
You’ll find guidance on how to use pre-blended emulsifiers, and how much to use, in the organic and general skin & hair care versions of the program, under ‘o/w cream – pre-blended emulsifiers’.
What are the pros and cons of using pre-blended emulsifiers?
When a pre-blended emulsifier is used, additional individual emulsifiers are not commonly added, nor needed, which can make the formulation of creams and lotions significantly easier. It can also help reduce logistical issues with ordering individual materials, as well as economy of scale savings where full packs of ingredients can be used instead of several individual ingredients being only partially used. You still need to have the other required elements of your cream or lotion for best results: water, humectant, gum (or gelling agent), oils, preservative, antioxidant, aromatic substance and actives – but the use of the pre-blended emulsifier means you can work with just one ingredient as the emulsifying agent, instead of the previous two, three or even four materials.
One of the downsides to using pre-blended emulsifiers can be the extra cost – because they have had significant research into their development, including testing in various types of emulsifiers, they typically cost more than individual emulsifying ingredients. The supplier must also heat, mix, cool and pack the blended material, which adds to processing time and energy, reflected in the additional price per pack. But, they can save you time, and possible cost savings from sourcing from several suppliers, and you may have less wasted part-packs than if you were using several different ingredients in their place.
Another downside to pre-blended emulsifiers is because they are pre-blended, you can’t adjust the anionic or non-ionic content if you want to. For example, when creating serums, you may want a very small input of anionic emulsifier compared to non-ionic materials, in which case, you would better off choosing individual emulsifiers to create your formulas. Another example is a crème cleanser, where you may want a higher input of anionic emulsifier compared to non-ionic emulsifiers, for more effective make-up removal – again, you would better to choose individual materials and create your crème cleanser formula using more traditional cosmetic formulation approaches. Finally, an anionic pre-blended material is not at all suitable in hair conditioning products, where a cationic emulsifier and non-ionic emulsifiers are required instead.
Which is best to use: pre-blended emulsifiers or blends of individual emulsifiers?
So – which emulsifiers should you use for your creams and lotions? The pre-blended type, which we’ve just discussed, or the more traditional way of putting an emulsion together, using a combination of single and blended emulsifiers as presented earlier in this blog?
The choice of cosmetic emulsifiers really depends on what your target market is looking for in the finished product (in terms of sensory and performance) and price – but this is the fun part of cosmetic formulation!
You are best to try out pre-blended emulsifiers as well as the more traditional way of putting creams and lotions together by preparing formulation samples, and test your finished products to evaluate how they feel on application, while being rubbed in, and lasting hydration and sensory impact. Once you have samples made and compared these aspects, also consider long term stability of the cosmetic formula and cost to manufacture. Then, ask yourself: which product, given all these parameters, will my target market find more appealing?
If you are making product for yourself, choose whichever one you prefer! If you are making cosmetic formulas to suit a specific target market, then consider what best addresses their preferences. Afterall, consumers don’t usually understand the chemistry of a cosmetic product, but they do know what they like the feel of, and what they consider good value for money.
And there, my dear formulating friend, you will find your answer.
Above all, have fun playing with different cosmetic formulas and ingredient samples in the meantime…
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- Find out more and get creating Makeup formulas
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