Great so herbs aren't worth a damn in vivo and pharmaceuticals mess up our mitochondria and make us worse.
I would not say supplements are not worth a damn: two of the medications that had the most useful effects for my ME/CFS and accompanying conditions are supplements: N-acetyl-glucosamine (NAG) for anxiety, and high dose selenium for ME/CFS. However, it's much more of a trial and error situation with supplements; here are no tests that could have told me that NAG would be very effective for my generalized anxiety disorder. But there are a number of supplements that have been shown in studies to have mildly beneficial effects for ME/CFS.
There's little evidence that drugs damage mitochondria, except perhaps for a few drugs like metformin, tetracycline and minocycline. And even in these cases, you are only likely to experience adverse mitochondrial effects from this if you have a mitochondrial disease. I started a thread on this subject
here. Mitochondria give birth to new mitochondria every few days to a few weeks, so all your mitochondria get replaced by new ones after a few weeks.
Thus unless there is damage to the mitochondrial DNA (which would then be passed down to new mitochondria), your mitochondria will always regenerate themselves in pristine from. Note that fluoroquinolone antibiotics can cause a "selective loss of mitochondrial DNA", see
this paper; so that's one to watch out for.
Also the supplement berberine, found in the herb barberry, has
been shown to have toxic effects on mitochondria.