Tamanu oil & Butter as a cure for Psoriasis?

Has anyone used this and if so which one did you buy and has it helped? I read recently that this may help psoriasis? My psoriasis was getting better after using dead sea salt in the bath, Exorex and moogoo soothing cream and diprosalic but I has a course of steroids and my skin started flaring up badly and I am stuck with it again! nothing that usually works is helping. Often adding Turmeric to food and sea salt baths calms it down if not quite able to clear it - but this time it is awful! I read that Tamanu oil is good - but as it is expensive I dont want to chase something in the hope again. Also need to make sure it is pure. I look forward to hear form anyone who has tried it..