Role of vitamin B-12 in treatment of psoriasis Vitamin B-12 is a water-soluble vitamin belonging to the B-complex family of vitamins. Many important biological processes in your body, including red blood cell formation and nervous system function, require vitamin B-12. Psoriasis is a chronic skin condition in which areas of skin become inflamed and develop into rough, dry patches. Treating psoriasis can be challenging, causing people to search for many different remedies. One possible remedy is treatment with vitamin B-12; however, the available research concerning this treatment has produced conflicting results.