Its value as a topical treatment in inhibiting scarring has, however, been demonstrated [550,573], and Aryl hydrocarbon receptor agonists (of which KYNA is one, and including the FDA-approved tapinarof [729,730]) have been shown to have benefits in both psoriasis and atopic dermatitis [731,732,733,734,735]. This evidence concerns the gene AHR and atopic eczema.