If you're low on salt with a high heart rate, salt will fix the problem. But if you're low on magnesium, salt won't fix high heart rate, but a beta blocker might. However, a beta blocker can't fix other low-magnesium issues.
Likewise with progesterone, a hormone that is such a blessing for so many reasons. Progesterone, magnesium, salt, iodine, and potassium -- not the only important issues, but well worth sorting out.