Okay, I feel like a real jerk for not reviewing this years ago :/
I used to have such bad, flaky psoriasis on my scalp. So bad. I would get little specks on my shoulders. I would shake off my cardigan and it would look like snow. It was really gross and embarrassing.... If I were shopping and saw a clothing item I liked, I would purposely get a lighter colour and never black because I knew it would show.
I tried a few different things. Clarifying shampoo. Head and Shoulders ( i know, I know), etc. Ages ago I used a tar shampoo but it stained my light hair a bit and it smelt awful. Also, for some reason when I wanted to cave and buy that shampoo I couldn't find it anywhere.
So everyone recommended T-gel. I gave it a shot. I used the extra strength. The first day, I saw improvement. Not perfect, but maybe a good 60% reduction in flaking. Second wash, 80%, and by the third wash I couldn't even tell I had psoriasis. It wasn't itchy. It wasn't flaky. I basically do not shed at all. I have used this for about 4 years now and it has never failed me.
I have curly hair, so I only wash my hair once or twice a week. This product is still just as effective for me. I don't find it too drying or any ill-effects. It also does not smell amazing- very moth ball, but I find it goes away. I shampoo with my regular shampoo, then rub this into my scalp for at least 30 seconds. I let it sit for about 5 minutes or so (I also put a conditioning treatment on my ends during this time). Wash my body, shave etc whatever and then rinse out both this shampoo and the conditioner, then I just add a little bit of regular conditioner to my ends to make sure they don't get dry, rinse, done :) After styling etc there's no moth ball smell, for me at least.
I will say that one time my local drug store was out of the extra strength so I got regular. It worked okay, but I could tell the difference. I would say it felt about 30% less effective. If you have psoriasis, give this a try. It is a godsend to me. I will repurchase this forever.