There has been a lot of discussion of hydroxychloroquine (see the megathread on Effective Altruism Coronavirus Discussion, note you need to answer two questions to gain access). Doctors treating COVID-19 have rated hydroxychloroquine the most effective drug based on their experience. But on the other hand, results have been mixed with a recent RCT showing no effect.
At this stage how strong is the evidence for hydroxychloroquine and if it works, how effective does it appear to be as a treatment?
Disclaimer: Please seek medical advice before taking any substance, particularly those like hydroxychloroquine that have known side effects.