An animal study involving psoriasis in mice found that black seed oil could effectively reduce the skin thickening effect of psoriasis in the mouse’s tail [8].
The oil produced a well-defined granular layer in the epidermis (the surface layer of skin). The granular layer is often absent in psoriasis lesions, so this may be the mechanism through which black seed oil improves psoriasis symptoms.
While animal study results can’t always be extrapolated to humans, the researchers concluded that black seed oil has “antipsoriatic activity”. They agree that topical application could be useful for managing psoriasis.