I apply mine on the inner arms and wrists....for systemic absorption.

But you can pick a target that bothers you... like charleyhorse type cramps and apply there daily to see if this lotion prevents further. I find that one application lasts days this way, then wears off, then you return and do it again.

I don't think applying large amounts is wise...so small areas once every few days and rotating to a new area each day...is best. I am finding this magnesium lotion lowers my high blood pressure. So you don't want those side effects or too much daily. Apply at night and you might feel better and sleep better.