Skin is a complex biological model that is nonetheless highly approachable. Several methods exist to study it, including animal skin and human skin, both in vitro and in vivo models; regional variation models; and stem cell and hair follicle biological models. Through such models, pharmaceutical preparations in dermatology have been found to affect cell regulation. However, the US Food and Drug Administration (FDA) usually exempts dose justifications for dermatologic preparations. With oral and parenteral dosing, dose justification is generally done during phase II. With topicals, a relatively arbitrary percentage is often dosed—without the benefit of dose justifications. As a result, the presence of any hormetic effects could be missed.