It’s not dangerous but you need to be careful when using it. I just ordered some from reliablerxpharmacy.
It’s my second time using that site and I have no intention to seek different source.
You can’t get it in USA without prescription. You can try curology, they match you with a derm and prescribe custom formula just for your issues. But they will start you at very low dose of retin a. That’s why I stopped them, I wanted higher strength.