I make a sulfate free shampoo for limited sale. Till now Guar hydroxypropyltrimonium chloride had sufficed as a thickener, but recently there is a demand to incorporate Salicylic Acid in the shampoo
To accommodate the very low pH of 4, I've tried both CMC and HPMC in the following formula:
Panthenol B5 0.1
PEG-7 GC 0.7
ARS Oil 0.3
Vit E 0.1
Coco Glucoside 5.88049
Decyl Glucoside 4.22576
Salicylic Acid 2
Potassium Sorbate 0.3
HPMC in distilled water heated to 60°C and sprinkled into a vortex separates over the course of an hour. When filled in a transparent bottle, the top third is thickened and the solution below is thin as water.
Does anyone have experience using HPMC at such pH levels?