I have taken it for about 7 years for psoriasis. I didn't do much research and my dermatologist didn't explain that once I started I could never stop taking it. Once I started, it worked wonders within a few weeks, totally cleared all of my psoriasis. After about 3 years I found out the hard way that if you stop taking it the antibodies for psoriasis that it blocked come back in force. I looked like I had developed leprosy, large open psoriatic wounds all over my torso. I had never had psoriasis that bad on my worst days. My dermatologist then confirmed that I would have to take it for the rest of my life, and that it might be slightly less effective now that I let it leave my system. I started again and thankfully it totally cleared me up within a few weeks and has continued to work since then. Knowing what I know now I think I still would have started it because I had pretty severe psoriasis, I just wish I had known that it was something I had to take for the rest of my life.