Niacinamide (Vitamin B3) has some scientific basis for its use in supporting or treating psoriasis, though the evidence is limited and not robust. Niacinamide is known for its anti-inflammatory properties and its ability to modulate immune responses, which are relevant given that psoriasis is an immune-mediated inflammatory skin disorder. In vitro studies and small clinical trials have demonstrated that niacinamide can help reduce inflammation and improve skin barrier function, both of which are compromised in psoriasis.

A handful of small-scale studies have explored the use of topical niacinamide for psoriasis, particularly in combination with other treatments, such as topical steroids. Some of these studies reported improvements in scaling, erythema, and skin hydration. However, these trials generally included small sample sizes, short durations, and often combined niacinamide with other active agents, making it difficult to isolate its specific effects. There is a lack of large, high-quality randomized controlled trials evaluating oral or topical niacinamide as a monotherapy for psoriasis.

Overall, while the theoretical rationale and some preliminary data suggest potential benefit, the current level of scientific evidence supporting niacinamide’s use in psoriasis is weak to modest. Thus, it may be considered as an adjunctive therapy based on its safety profile, but it is not a first-line or well-validated treatment for this condition.