It's hard to know exactly which emulsification system you want to use in a lotion until you try it. There are so many considerations when choosing an emulsifier...cost, availability, ease of use, how to incorporate it, what ingredients you want to avoid, what ingredients you want to emulsify, and so on.
My first consideration is always ease of use. I want something I know is going to work - when I follow good manufacturing procedures - and will be consistent every time. I think it's safe to assume that if you follow the instructions for use, it will work.
My next consideration is skin feel. And each of us has our own definition of what we want in a lotion. I'm a big fan of a glidy, non-whitening, slightly greasy lotion. But you might prefer something thicker, less greasy, more powdery and so on. So please keep this in mind when choosing an emulsifier. Assuming it emulsifies well, I think this is going to be one of your top priorities.
My next consideration is availability. I don't have a lot of choices living in Canada and it's not a good option to order from the States. The shipping charges, minimum order amounts, and costs incurred at the border can raise the price 75%.
Remember, these are only my opinions. Please share your ideas on various emulsifiers in the comments section! And tell us why you like them!
EMULSIFYING WAX NF (various manufacturers)
INCI: Cetearyl alcohol and Polysorbate 60
Comes in pellet or flake form and must be heated and held to use.
As you can see, this is a high HLB emulsifier (polysorbate 60, HLB 14.9) and a low HLB emulsifier (cetearyl alcohol, HLB 4.5 to 4.7) combined to create an emulsifying system. The cetearyl alcohol is a fatty alcohol that offers some low level conditioning, emolliency, and thickening (much like cetyl alcohol).
Emulsifying wax offers emulsification with the addition of emolliency (the cetearyl alcohol is like cetyl alcohol). So your lotions will have more slip and glide and more greasiness than some other emulsifiers. Some of us (including me) like this feeling and others find it annoying. You can add IPM to the mix to reduce the greasiness, choose other esters, or use dryer oils like macadamia nut or hazelnut oil.
There seems to be some debate about the HLB of cetearyl alcohol with some saying it is as high as 15.5 and as low as 4.5. Since it makes no sense to me that you would combine two high HLB emulsifiers and have them work, I'm going with the lower number. Having said this, I find emulsifying wax NF is not as reliable as I would like, and I tend to use it only in anhydrous scrubs or bars in which I want emulsification on the spot without worrying about stability.
Note: If you find an emulsifying wax that isn't cetearyl alcohol and polysorbate 60, it is NOT emulsifying wax NF (the NF stands for National Formulary and is a standard). It may not work as well as regular e-wax, so check the INCI posted by your supplier.
POLAWAX (only made by Croda)
INCI: Emulsifying wax NF
Comes in a pellet form and must be heated and held to use.
Use at 2 to 10% of your lotion.
Croda won't tell us what is in Polawax, but I love the stuff. It works really well and the only fails I've had using it are definitely my fault! I use it 25% of my oil phase (so if I have 10% oils, I'd use 2.5%) and it does make your lotions slightly more greasy than using something like BTMS. (But only slightly...)
Polawax is more expensive than regular e-wax. I find it worth the difference - you might not. It does all the things emulsifying wax NF might do - adds a little emolliency, emulsifies oil and water lotions - but I find it more stable and less likely to separate. I have no idea why this is because I don't know the ingredients in Polawax.
For a technical data sheet, please click here.
INCI: Behentrimonium methosulfate (and) cetyl alcohol (and) butylene glycol
BTMS is a great emulsifier, but it imparts a dryer, less greasy feel to your lotions. As it is cationic, you are going to be making a cationic lotion. The e-wax and most other emulsifiers are non-ionic, meaning they carry no electrical charge. (Cationic lotions are positively charged). As a result, some preservatives may not work well with BTMS as the emulsifier - Tinosan, for one - so always check out how the other ingredients in your lotion will be affected by changing to a cationic emulsifier.
BTMS-50 will offer skin conditioning benefits to your lotions, which is always a good thing. And if you're using a lot of silicones, BTMS is the best emulsifier for the job. You can make lotions with up to 50% silicones with BTMS.
For more information on using BTMS-50 as a hair conditioner, please click here.
For the most part, if you have a recipe calling for one of these emulsifiers, you can substitute it for another one without a lot of difficulty. You are going to get a different skin feel - especially with the BTMS - and I'd keep notes as to what you like.
As a secondary note, I always use a co-emulsifier or thickener like a fatty acid (like stearic acid) or fatty alcohol (like cetyl alcohol) in my lotions. Generally I use stearic for creams, cetyl for lotions. (What's the difference between a cream and a lotion? Join me on October 5th for a discussion on this topic!)
For some great information on emulsifiers from the Herbarie please check out these links...