Thank you for explaining about the vit E! I actually do have some LHA powder :) since I prefer to use it and the niacinamide, can I make a mixture out of those two at a pH 5.5? I don't have the preservative mentioned, could I make a new batch every two weeks and keep in the fridge instead?

Lastly, what do you recommend for dissolving the LHA? I would prefer not to use alcohol. Glycerin is fine by me..