|What is it?||Glyceryl Stearate (and) PEG-100 Stearate is a very versatile non-ionic oil-in-water emulsifier that creates silky smooth, ultra-light emulsions. Most datasheets I’ve seen state the content of each Glyceryl Stearate and PEG-100 Stearate as 48–52%, which averages out to a 50/50 blend, though check the datasheet from your supplier for the particular one you have.
This emulsifier is manufactured by a lot of different companies, so it ends up having a lot of different names, including (but not limited to):
Because there are so many different manufacturers of this blend of ingredients it’s important you get specific information for the ingredient you’re using from your supplier as there may be variations between products.
|INCI||Glyceryl Stearate (and) PEG-100 Stearate|
|Appearance||I’ve only seen it as brittle white flakes, but some manufacturers sell it as a powder or in pellets.|
|Usage rate||1–25%, depending on the use. SEPPIC lists 5% for a fluid lotion, 10% for lotion, 15% for a thick lotion, 20% for a fluid cream, and 25% for a thick cream.|
|Texture||Brittle, hard; weightless in emulsions.|
|Absorbency Speed||Very light|
|Approximate Melting Point||50–60°C (122–140°F)|
|pH||5.5–7 (3 % solution); tolerates a final pH range of approximately 4–9.|
|Why do we use it in formulations?||Glyceryl Stearate (and) PEG-100 Stearate is a very effective and crazy versatile emulsifier. It can be used to create everything from sprayable milks to ultra-thick emulsified body butters, and everything in between!
Unlike emulsifying waxes like Polawax, Emulsifying Wax NF, Olivem 1000, and Ritamulse SCG, Glyceryl Stearate (and) PEG-100 Stearate does not substantially thicken emulsions, even in emulsions with very large oil phases. It is also substantially more stable in very thin emulsions.
For example, let’s imagine we have four different emulsions; 2 emulsified with Polawax, and 2 emulsified with Glyceryl Stearate (and) PEG-100 Stearate. One of each emulsifier has a 15% oil phase, and the other two have a 30% oil phase—the only ingredients in the oil phase are a liquid oil and the emulsifier. There are no added thickeners, like gums or fatty alcohols (cetyl alcohol, cetearyl alcohol, etc.)
The Polawax emulsions will have drastically different viscosities. The 15% one will be fairly thin, but still lotion-y. It would work well in a pump-top bottle, or possibly even a bottle with a treatment pump cap. The 30% one will be more like a cream; thick and rich, and much better suited to a jar or tub.
The Glyceryl Stearate (and) PEG-100 Stearate emulsions will have very similar viscosities. The 15% one will be about the consistency of partly skimmed milk, while the 30% one will be more like cream. The 30% one is more viscous because the inner phase (the oil phase) is larger, but that viscosity difference is pretty small—especially when compared to differing phase sizes in an emulsion made with Polawax. Both Glyceryl Stearate (and) PEG-100 Stearate emulsions could be packaged in a spray bottle, and are far too thin for any sort of pump bottle or jar.
Because Glyceryl Stearate (and) PEG-100 Stearate does not thicken emulsions, it gives us the ability to control the viscosity and oil phase size independently. For instance, you can create an emulsion with a 50% oil phase and decide if you want it to be a thinner, pumpable lotion or a thick, solid cream. You can also choose what you want to thicken it with, allowing you significantly more control over the skin feel of the finished product. With an emulsifying wax like Polawax, that product could only be solid, and the skin feel will be harder to adjust given the unavoidable presence of the thickeners in Polawax.
Additionally, because Glyceryl Stearate (and) PEG-100 Stearate doesn’t add viscosity to our emulsions, it has the ability to create far lighter feeling emulsions—in that way, it’s almost ‘invisible’ in your formulations. If you want to add the fluffy creaminess and weight of cetearyl alcohol, you’ll have to add it yourself—if you used Emulsifying Wax NF instead, that already contains 65–80% cetearyl alcohol, so you can’t avoid it.
Glyceryl Stearate (and) PEG-100 Stearate also works at lower rates than more common emulsifying waxes. Compared to Emulsifying Wax NF, Glyceryl Stearate (and) PEG-100 Stearate contains a higher percentage of the emulsifying ingredient. Emulsifying Wax NF contains 20–35% Polysorbate 60, while Glyceryl Stearate (and) PEG-100 Stearate contains approximately 50% PEG-100 Stearate. I’ve seen (and successfully used) Glyceryl Stearate (and) PEG-100 Stearate at 9–17% of the oil phase, compared to 20–25% for emulsifying waxes like Polawax, Emulsifying Wax NF, Olivem 1000, and Ritamulse SCG.
|Do you need it?||I highly recommend it if you love making lotions—it gives you far more control over your emulsions than emulsifying waxes like Polawax and Ritamulse SCG.|
|Refined or unrefined?||Glyceryl Stearate (and) PEG-100 Stearate only exists as a refined product.|
|Strengths||It’s extremely versatile, allowing you to independently adjust the viscosity and oil phase size of your formulations. It easily creates stable emulsions at low usage rates and works brilliantly over a wide variety of oil phase sizes. It’s lightweight, inexpensive, and very effective.|
|Weaknesses||It isn’t considered natural; that doesn’t bother me as it is a perfectly safe ingredient, but I can’t offer a suitable naturally-accepted alternative at this time.|
|Alternatives & Substitutions||Glyceryl Stearate (and) PEG-100 Stearate is a tricky ingredient to substitute out. Generally speaking, you’ll need another complete emulsifying wax (something like Emulsifying Wax NF or Olivem 1000), but those complete emulsifying waxes contribute significantly more thickening to finished products, meaning formulations designed to work with Glyceryl Stearate (and) PEG-100 Stearate will likely be significantly more viscous if you use a thickening emulsifying wax in its place. Depending on the formulation you may be able to adequately compensate by removing any additional fatty thickeners, but this will take some experimenting to get right.
If the formulation is for an ultra-light body milk or a very thick emulsified body butter type project, it will be difficult to substitute the emulsifier. You will likely be in re-formulation territory, or you will need to accept a more viscous and/or waxier/heavier end product.
|How to Work with It||Include Glyceryl Stearate (and) PEG-100 Stearate in your heated oil phase.|
|Storage & Shelf Life||Stored somewhere cool, dark, and dry, Glyceryl Stearate (and) PEG-100 Stearate should last at least two years.|
|Tips, Tricks, and Quirks||Glyceryl Stearate (and) PEG-100 Stearate is different from Glyceryl Stearate SE, though both are emulsifiers.
The Body Shop uses Glyceryl Stearate (and) PEG-100 Stearate to emulsify their signature body butters!
|Recommended starter amount||100g (3.5oz)|
|Where to Buy it||Buy it from an online DIY ingredient supplier. In the USA you can purchase it from Making Cosmetics and Lotion Crafter. In Canada, you can purchase it from Windy Point Soap Making Supplies. In the UK and EU, you can purchase it from Mystic Moments. In Australia, N Essentials has it.|