I wonder whether 'Those' should be replaced by 'It' because 'Those' refers to acupuncture. I think if 'Those' refers to 'some studies', "Those have actually been shown to be" should be rewritten as "Those have actually shown it is". This comes up in a YouTube video https://youtu.be/JrzumXTQQ2M?t=510
and there are some studies that have compared acupuncture with some of the standard oral medications that we have like topiramate and the beta blockers. Those have actually been shown to be helpful for migraine prevention and can cause less side effects than oral medications.