Safety and Sourcing of Topical Cannabinoids: Many Questions,Few Answers

BackgroundTopical cannabinoid products are increasingly being recommended and used for a variety of dermatologic conditions. Despite this, safety and efficacy data of topical preparations are lacking, and the differences between topical and oral formulations are not well characterized.ObjectiveWe reviewed the literature to gather published data on topical cannabinoid products and the differences between topical and oral formulations.MethodsThe PubMed/MEDLINE literature database was searched using the terms “cannabinoids,” “cannabidiol,” “CBD,” “topical cannabidiol,” “transdermal cannabidiol,” “hemp” and “skin.” Results were manually screened to identify published data on topical formulations of cannabinoids or cannabidiol use, adverse effects, sourcing, and solubility.ResultsTopical formulations of cannabinoids might be more nuanced than oral formulations, due not only to dosing differences, but also to potential differences in transcutaneous absorption. Safety and efficacy might need to be evaluated on a product-by-product basis until universal standards for topical preparations are better established. CONCLUSION: Topical cannabinoid products might be an important addition to the dermatologic armamentarium, with the potential to dose cannabinoids directly to the skin while minimizing systemic exposure. However, before this can be done reliably, important formulation parameters must be established and verified.