“…Hence, if only because of their sheer abundance, topical therapies that aim to reverse Cer deficiency, a characteristic of atopic dermatitis, typically employ Cer or Cerlike molecules, and often in large quantities [4]. Yet, three issues confront those who wish to use natural or skin-identical Cer in such 'barrier repair therapeutics': (1) nature-identical, synthetic Cer are extremely expensive (typically $2000-10,000/ kg); (2) less-expensive, naturally occurring Cer derive primarily from bovine central nervous system, raising concerns about transmission of bovine spongiform encephalopathy ('mad cow disease') [5]; (3) excess intracellular Cer can be toxic to cells, both inhibiting growth and inducing apoptosis [6,7].…”