I don't remember the doses, but a few years back I had a doc prescribe it for me. I told him I was going on vacation and burned very easy. I told him about this and he had never heard of it. He looked it up in the PDR, called a pharmacist and viola, I had a script.
It worked pretty decent. I take a tablet before tanning and for an irish/scandanavian lad, had a real decent look to my skin. I have since read that you should tan at night and avoid sunlight to the eyes as you may develp cataracts. I don't know if that is valid or not, but you will get tan.
You can burn very easily on Oxsoralen. I would recommend you only use it in a tanning bed where you can easily control your UV exposure. Also, wear some chapstick and goggles. Also, wear UV protection sunglasses when outside (sunny or cloudy) to prevent cataracts.
Oxsoralen will help melanin production producing a skin pigmentation change (tanning). However, you will likely burn more easily so start slowly and work your way up to more tanning time. Oxsoralen can also be hepatotoxic, so don't exceed the recommended dose, and I would not take with oral AAS. It will get your quite brown if used correctly.
These work incredibly well. I take 2 10mg caps about 2 hours before I tan. I use tanning bed and the sun. 2 weeks later I am darker than a brazilian. Made an incredible difference. Never had a problem with my eyes although I did seem more sensitive to bright light. Use them only on the days you tan.