Magnesium supplementation seems to used by several doctors treating ME. Recently, I started Freddd's b12 protocol but had to come off it because of what seemed to be symptoms of induced magnesium and potassium deficiency. I couldn't seem to supplement them enough to stop the symptoms. I was using Mg oil for transdermal application and an occasional Epsom salts bath. I'm going to restart Freddd's protocol at lower b12 doses to try to keep this under control but am thinking I should address any underlying magnesium deficiency. I haven't had a blood test but apparently serum levels aren't anyway helpful for detecting a deficiency. Some questions: 1. IV vs transdermal: Dr Myhill and Dr Nathan (who did the study with richvank on his methylation/b12 protocol), for example, both give patients Mg supplementation in the form of injections or IV drips. I'm wondering why they would do this, given that Mg can be taken transdermally in the form of an oil (actually a highly saturated solution of Mg chloride) which of course doesn't hurt and doesn't require you to get a doctor to cooperate (a major obstacle for many of us). A lot of people (me included) have stomach problems if we take oral supplementation and I understand that absorption of Mg in the gut is anyway highly variable so I can see why oral supplementation might not be the best method. But IV vs transdermal? 2. Overdosage: Dr Myhill writes in her e-book that oral Mg is extremely safe because too much causes diarrhoea. However, presumably this is not the case for IV/transdermal. How can we tell if we've taken too much via the transdermal oil and/or Epsom salts bath route? Is there a likely safe dose? I was thinking of 360mg via Mg oil transdermally plus a 500g Epsom salts bath every other night. 3. Test dose for deficiency: Freddd's b12 protocol can induce potassium deficiency. He recommends a test dose of 500mg of potassium if, on his b12 protocol, you start to experience symptoms of possible potassium deficiency. If you feel better within 30 minutes, it indicates that potassium deficiency was indeed your problem and that you should increase your daily dose. Is there a similar test for Mg deficiency (either an acute one induced by Freddd's protocol or a chronic one)? If so, what's the test dose and how long does it take to see a response to that dose?