What are your sources for the kinds of magnesium you take?

I rely a great deal on Dr. Google myself, but there are sources and sources!

I try to only rely on ones with doctors involved (even nutritionists are suspect, IMO. For one thing, anyone can claim to be one and for another I'm not a believer in anything that sounds "woo-woo" to me. That even includes online doctors, as some have gone over the line in marketing products - and books - they benefit from.

The internet is completely unpoliced and there's just too much completely contradictory "information" out there - that is, information that SOUNDS authoritative.

(Just try to research the KETO diet, for example!!)

Even taking something based on a dictum from an online someone with mysterious letters after their name, is questionable. Not unless you've tried it for a good while. And also, made some kind of effort to compare different agents that claim to do the same thing.

I say that as someone who takes a bucketful of supplements, and am gradually finding out ones that shouldn't be taken together, and ones that have effects that can be dangerous (if indeed they contain what they claim! See below).

Besides which the great drug, PLACEBO can have the most powerful effect of all!

There was a well researched article in the NY Times a few years ago, for which chemists analyzed ingredients. Finding - that over half contain something other than claimed (including inert substances like sawdust). FYI Only the state of California has rules as to what is allowed to be sold according to tested contents - safety and that it contains what is claimed.

I wish I could get all my supplements with labels showing they've passed test in California! Instead, I'm spending a good deal on supplements that for the most part are not from knowable reliable brands. (I confess I often end up choosing the one with the most professional looking labels! But then I do almost the same thing with wine, on the rare occasion I purchase it - labels and price! I'd use a blush emoticon if they were an option here.)