First of all “Welcome” though you may have been ‘here’ longer than I have 
No we aren’t ‘scientific’ as others have said and are at a great resource for generating conjectures or hypothesis, perhaps some case notes but even that won’t be approximately valid for most of us.
Half the time I can’t even tell you WHICH intervention I did to cause a change. And if all the interventions are cheap & easy and perhaps needed it maybe be a long time (or never) before trying to isolate the cause will even be interesting to me.
In the last year, I’ve done (at least): Keto, Carnivore, Extended Fasting, Mega-Vitamins (with dozens of subtances), dropped statin drug (perhaps most important FOR ME*), and Nootroopics (all legal, some prescriptions by Doc though I would consider others if a source were available), and Hypnosis/NLP.
Notice that last: Hypnosis/NLP. I am trained in this field and do my best to IMPLEMENT THE PLACEBO and other psychological effects.
After all, placebos are 40% as effective a morphine in controlling pain and infinitely cheaper with no discernable or identifiable side-effects.
What’s improving my health? All of the above???
- The statins drug was almost certainly making me stupid and almost incapable of long term focus or even getting through a day without extreme drowsiness. (Can’t prove it 100% though.) My wife too I believe, but almost certainly true for me.
Most of the above is fun or has some other use like weight loss, so I don’t much care. I could drop supplements that aren’t giving me a good ROI but they are cheap enough it’s not worth isolating them to decide which to drop first, and maybe there is some weird interaction where something else only works when the one I would drop is present.
What I do know is this:
My 4 years missing motivation & energy is BACK, or on the way back, and it showing effect on the real world in improving my life and my wife’s life (and maybe others.)
Placebo and all, I want it all – for now.