The strongest evidence for ivermectin effectiveness is how much it has been demonized by the media, the CDC, and by the medical establishment. As far as having ironclad scientific evidence, it's not there. Ivermectin is an off-patent drug that costs pennies to manufacture. There is no money in studying its effectiness. Funding for studies comes from the pharma industry and they're all pushing vaccines. But if you want a study, here is the latest and largest one: https://www.nejm.org/doi/full/10.1056/NEJMoa2115869 You'll see articles in the media say that this study proves that ivermectin is doesn't work against covid. They are lies. There is a clear signal and according to the study authors the study is simply underpowered: it needed way more participants to show the effect. IMO the study was designed to fail so it could be touted as a failure for ivermectin. It all comes down to what you consider to be sufficient evidence. One could say that there is insufficient evidence that ivermectin helps with covid, and just looking at the studies, if your standard for evidence is high enough, that's definitely true.