The Impact of US Food and Drug Administration's Advisory and Enforcement Actions on US Sales of Esco Bars Products in 2023: Synthetic Control Approach

Abstract

Background: In 2023, Esco Bars was the second most commonly reported e-cigarette brand used among US middle and high school student e-cigarette users. These products have not been authorized for sale in the United States by the US Food and Drug Administration (FDA). On May 12, 2025, and May 25, 2023, the FDA issued an import alert and a warning letter, respectively, to the manufacturer requiring them to immediately remove these unauthorized products from the market. On June 22, 2023, and July 27, 2023, the FDA also issued warning letters to US retailers and distributors, respectively, regarding the illicit sale of these unauthorized products. This study evaluated the impact of these advisory and enforcement actions on retail sales of Esco Bars in the United States.

Objective: We evaluated the impact of these 2023 FDA advisory and enforcement actions on illicit sales of unauthorized Esco Bars to better inform future regulatory decision-making.

Methods: This study used a synthetic control method to evaluate the impact of 2023 FDA advisory and enforcement actions on Esco Bars sales based on weekly sales data from the NielsenIQ Retail Measurement Service between January 1, 2023, and December 30, 2023. Data came from the 48 contiguous states and were not available for internet and vape shop sales. First, we standardized the data by transforming the weekly sales into z scores. Second, we created a synthetic comparison for Esco Bars sales based on sales of other e-cigarettes for which the FDA did not take action during the analytical period. Finally, we calculated the difference in sales between Esco Bars and the comparison group before and after the FDA actions. To assess the robustness of the findings, we used other standardization methods for sensitivity analyses.

Results: By the last week of 2023, actual Esco Bars' weekly sales were 68.5% lower than the estimated sales in the comparison group (P=.02). Over the 5-month period following FDA advisory and enforcement actions, Esco Bars product sales were reduced by approximately 1.7 million equivalized units (P=.06). These findings were robust across sensitivity analyses.

Conclusions: The FDA's advisory and enforcement actions substantially reduced sales of Esco Bars products in the United States, with a sustained impact noted over a 5-month period. These findings underscore the importance and impact of FDA actions against unauthorized tobacco products as part of a comprehensive regulatory approach.

Keywords: DiD; FDA; FDA advisory and enforcement actions; SCM; US Food and Drug Administration; difference-in-differences; illicit sales of e-cigarettes; synthetic control method; unauthorized e-cigarettes.