I am in the medical field and I would beg to differ on the "well tested" part of prescription drugs. Many of them were tested on male populations, some are fast tracked, and many of them seem to have side effects including death!?
Have you listened to the adds on some of these newer drugs. Your psoriasis will get better, maybe 70%, but your kidneys might fail and your immune system will be compromised, etc etc etc! There are studies done on many vitamins/minerals/natural supplements. Often these are done in other countries or Learning institutions because there is no money to be gained for big Pharma. They can't patent natural. No money means less studies and more synthetics.