• Welcome to Phoenix Rising!

    Created in 2008, Phoenix Rising is the largest and oldest forum dedicated to furthering the understanding of and finding treatments for complex chronic illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia (FM), long COVID, postural orthostatic tachycardia syndrome (POTS), mast cell activation syndrome (MCAS), and allied diseases.

    To register, simply click the Register button at the top right.

Do you take Magnesium even if your serum levels are normal?


There is no kinship like the one we share!
If so, how often do you check your blood levels of magnesium, thanks!


Hoarder of biscuits
I have taken/am still taking Mg even though my serum levels have been/are normal or even above normal. My highest serum Mg was 2.5mEq/L, with a ref range of 1.3 - 2.1 mEq/L. That was nearly ten years years ago. I also had several other Mg levels at or above the upper limit of normal around that time.

When I began treatment for erythromelalgia, using higher than usual amounts of magnesium, my rheumatologist checked my serum level once/month for a total of three times. (His instructions were to not take more than 1200mg/day). Then his successor checked serum magnesium about every 6 months.

The other posters are correct in stating that deficiencies can't be determined by serum, and you would need to depend on a RBC magnesium to detect a deficiency. However, if you're trying to determine if you have too much magnesium, a serum magnesium is most expedient.

I've been able to detect large amounts other ways - my muscles took on the abnormal sensation of feeling like a rag doll, and of course, going to the toilet. If you hit the rag doll sensation, you know you've overdone it, but if your kidney function is good, the rag doll sensation should go away in a few hours.

As a doctor, you probably know more about electrolyte metabolism than 99% of us, but I hope my experience will be helpful to you.
Last edited: