I just started taking magnesium chloride 18 %, which is more tolerated by the gut. It's supposed to help with PMS, migraines, and acne. I'll let you know if I get any results with my acne. It isn't severe, but I always have blackheads, sometimes the occasional zit and I am 37 years old. I have taken the RBC magnesium test, but haven't got my results to see if I am deficient. In Canada it costs $12.00 for the test.