If you are eating all organic produce and grass fed meats, you might not need to supplement magnesium. If you don't want to take pills, you can actually get magnesium through daily epsom salt baths (your body can only soak up what you need) or by using a magnesium oil spray (same about only what you need), but honestly, this is not enough for most people.

I personally take 800 mg Doctor's Best Brand Chelated Magnesium Glycinate. 400 mg in am, 400 mg in pm...

You will know it is too much when you get loose stool. Then you take one step back. The sodium is a HUGE part of not dumping potassium and magnesium. Personally, I get enough potassium from chicken and such, so if I supplement with potassium AT ALL (other than heavy exertion/huge heat/sweat days), I will dump magnesium like crazy. I supplement with pink salt crystals, mainly. I salt my food or pop the crystals like a pill...

The average need for magnesium varies from person to person, and changes with weight changes of 10% of body weight, as well as with treating years old deficiencies. Once you get level, you likely need less to stay level... But since magnesium is used in over 300 enzymatic processes in the body, I err on the side of pills... In my experience, I've seen people who need 200 mg of a more potent form of magnesium up on to 2000 mg of magnesium. You'll really just have to experiment.

Here is a link that might help you decide if your form of magnesium is the best one for you to use. https://forum.bulletproof.com/discussion/2078/bulletproof-magnesium-thread

EDITED TO ADD:

P.S. @Jinsenj - I think we're all crazy in our own ways... As for the rest, if you live and cope well, who cares?

Hi Tammy. I use a sports supplement to get my electrolytes and am feeling all the better for it. . It is an effervescent tablet that you just dissolve in water, sugar and carb free. . It is called High5 Zero Electrolyte Drink Tablets and I am sure you could source something similar in the US. I don't think you are nuts. All drugs have side effects and are best avoided.

I've been eating keto for a year.

Every few days I feel/perceive a bit of a need for a little more sodium in my system than I get from my food choices so will drink a cup of plain old McCormick's boullion/broth that has about 1100mg of sodium and maybe even add some salt to it for another ~300-500 grams.

I also take 100 mg of magnesium every night as a supplement.

I've never taken a potassium supplement.

That's it. I'm not downplaying the need for them because I have found both sodium supplementation and magnesium supplementation necessary. I just don't see a need for myself with any more than mentioned.

I eat regular food. Grassfed stuff is not something I budget for and I use plain old table salt. Do a google search for "foods high in potassium" or "foods high in magnesium" and eat those that are keto friendly. Avocados, spinach, salmon, mushrooms, nuts and seeds are a few.

Oh, I also take 1/2 dose of a multi-vitamin.