You mention having thyroid testing done but there is no Free T4 and Free T3 on there, from my reading T3 is the most important one though mainstream docs might not test you for it. You might have to seek out an alternative medicine doctor like a functional medicine doc, I've been seeing a functional medicine doc myself but if I had to start again I might go see a
Chronic-Fatigue-Syndrome specialist, looking on google I see there are lots in my area that I could call up, though, my current doc has been doing a decent job helping me find new meds and running tests. Did your doc look for thyroid antibodies? signs of autoimmune thyroid problems are usually tested for if thyroid problems are suspected or so I thought.
About the magnesium malate, malic acid is tested for on organic acid tests (an example here:
https://www.gdx.net/product/metabolic-analysis-test-organic-acids-urine look under analytes for malic aci, also check out a sample report in the lower right of the page to see what the levels mean and what kind of interventions are recommended, I haven't taken the test yet but have been considering testing out the meds and interventions the test recommends to see if they do anything for me since the test seems pricey, there are also other labs that will test for organic acids) here is a pic of malic acid as part of the
citric acid cycle
https://www.google.com/search?q=malic+acid&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjmh56Kh53UAhUHiVQKHb2tAt8Q_AUICygC#tbm=isch&q=malic+acid+cycle&imgrc=JzSC-JK2Ns4AtM: it is used to produce energy/atp and whatnot. I've been dealing with a lot of atp problems myself, I know cause many of the supplements that are recommended for atp work nicely for me or did.
Coenzyme Q10 and carnitine worked very nicely for me for a bit then sort of petered out though they do work occasionally, stopped taking them for a month or so then had a test done for each though quest which I'm hoping my insurance covers, my coq10 is borderline low so I'm planning on starting it up again at a higher dose, fortunately carnitine levels are fine. D-ribose, the sugar, still works well for me, I dissolve 2.5 grams of the stuff in water and drink a third of that every 30 min and repeat once it has all been consumed. Most advise 5g's of ribose 3x/day but that never worked nearly as well for me. I have heard that ribose has a very short half life so in that light the benefits I'm getting from the constant redosing would make sense, I think it was doctor Myhill who recommended that ribose be taken every 30 min in small doses, she works in the UK so you might be familiar with her work though she isn't accepting new patients or so I've heard.
On a side not I need to find a way to get insurance to pay for these alternative medicine lab tests since it's expensive to pay out of pocket.
I have found that this website doesn't focus very much on
Chronic-Fatigue-Syndrome which is unfortunate, check out phoenixrising.me and maybe get an account on there to post, they deal with nothing but
Chronic-Fatigue-Syndrome so I find the suggestions to be more relevant, at least in my case
Good luck dude