Vitamin B₁₂ contributes to acne by affecting the skin microbiota

Vitamin B₁₂ supplements have been shown to lead to acne development, but the mechanism behind this effect has remained unexplored. Now, Kang et al. show that transcriptional changes in the skin microbiota contribute to vitamin B₁₂–induced acne. Supplementing patients with vitamin B₁₂ reduced the expression of vitamin B₁₂ synthesis genes in Propionibacterium acnes and altered the transcriptome of the skin microbiota, resulting in the production of inflammation-inducing porphyrins. These studies demonstrate a clear link between changes in the skin microbiome and disease pathology.