How do I dissolve hydroquinone powder to make a 20% and 10% concentration?
I would like to add retinol and kojic acid to it as well.
I'd like the consistency to be thin like a gel so that it absorbs quicker.
Lastly, I'd like to add benzoic acid for preservation purposes.
I understand the concentrations are high but I have used them before, its just too expensive to keep buying from a compounding pharmacy. I'm using it for spot treatment of some hyper pigmentation (less than 1% of my body)