I was wondering what your recommendations are for increasing the viscosity of a Lactic Acid Serum.
It does not have to be very viscous, just slightly thicker than water. It will be packaged in a dropper bottle.
I also need it to be completely clear.
It will be 5% Lactic Acid with pH 4.
I prefer to use polymeric thickeners, but most are electrolyte sensitive.
I'm thinking about experimenting with Sepimax Zen and C10-30 Alkyl Acrylates Crosspolymer, as those are the most electrolyte resistant according to my research.
I prefer not to use Xanthan Gum, but will consider it if any of you have had a good experience, particularly with Soft or Clear.
Another possibility is high molecular weight Hyaluronic Acid.
One thing I thought about that might be kind of out there is using viscous humectants, like Methyl Gluceth-10, to increase viscosity. But I get the sense that I would have to use a lot, which might result in a sticky product.