Classic keratinocyte work by Yamaoka et al. showed that 10 μM Zn2+ silenced IFN-γ/TNF-α-driven iNOS transcription, cutting nitric-oxide flux by 70% [27]; our review’s observation of lowered erythema indices therefore dovetails with a cytokinic mechanism first described a quarter of a century ago. Here, IFNG is linked to Erythema.