Do as much research as you can on it and if you can’t find any where you live then let me know because I think it’s available online. I could point you in the right direction. There’s another brand called lugols. That ones only a couple of dollars per bottle but I don’t know how good it is and don’t want to risk changing brand just in case. I’ve been told however that it works well by someone who used to prescribe it in their last job. But if you do start taking it, whatever you do, do not suddenly stop taking it. You have to wean yourself off it.