I'm trying to figure out the correct amount of polysorbate 80 to use in my c serum. The only oil I use is 1% Vitamin E and I combine that with 1% polysorbate 80. It seems to stay emulsified for about a week or so but then starts to slowly start coming apart. Should I increase the amount of polysorbate 80 or do I need a secondary emulsifier? I would like to have it so it doesn't separate at all.
Thanks for any suggestions or tips