I've used it many times and never had any problems from it. And I have full blood panels every four months.
There is a huge misconception about using it. I have tried several different methods and the absolute BEST that I have found the last couple of times is :
Monday and Thursday .5mg taken at bed
Friday - 8 minutes tanning bed
Do that for three weeks and I get a very golden base tan.
If you use it more frequently, you WILL get darker moles and freckles. (I don't have any so nothing gets darks)
This stays active in you for a long time, you need to stop when you are two shades from the color you want to be or else you will just wind up too dark.