My mom had the same issue; this permanently resolved it. She thought it was old age.
I'll save you some time. Here's what I use after years of evaluating different products.
Mag glycinate:
https://www.amazon.com/dp/B0058HWV9S
Mag chloride spray:
https://www.amazon.com/Ancient-Minerals-Magnesium-Ultra-OptiMSM/dp/B008JSJ9HU/
Ioic minerals (for your water):