Vitamin B3 (Niacin) has been investigated as a potential adjunctive treatment for psoriasis, primarily because of its anti-inflammatory properties and its role in skin health. Scientific interest focuses on the use of nicotinamide (a form of vitamin B3) rather than nicotinic acid, as nicotinamide is better tolerated and lacks the flushing side effect. Several small studies and case reports suggest that topical or oral nicotinamide may help reduce inflammation and improve skin barrier function in psoriatic lesions. Niacin and its derivatives can modulate immune responses, inhibit neutrophil chemotaxis, and reduce the production of inflammatory cytokines, all of which are relevant in the pathogenesis of psoriasis.

However, the overall quality and quantity of evidence is limited. The majority of clinical data come from small-scale studies, pilot trials, and anecdotal reports rather than large, randomized controlled trials. Some topical niacinamide formulations have shown modest benefits in plaque reduction and symptom relief, whereas robust evidence for oral niacin is lacking. Current clinical guidelines do not recommend niacin as a standard therapy for psoriasis, but it may be used off-label in certain cases.

In summary, while there is some scientific rationale and preliminary evidence for the use of niacin (particularly nicotinamide) in psoriasis, the supporting data are not strong enough to justify widespread clinical use at this time.