Measuring commercial cannabis availability: findings from a multi-state surveillance study in the US.

Introduction: Cannabis legalization enables greater access to commercial cannabis among adults. Little is known about the extent to which demand for cannabis is met by licit or illicit markets among states with medical-only or recreational cannabis laws, or no legalization. Methods: Annual sales values of medical and recreational tetrahydrocannabinol (THC), illicit THC, hemp-derived cannabidiol (CBD) and hemp-derived THC were estimated for 2024 in 12 US states by combining and triangulating data from national- and state-level public sources, Euromonitor's Passport database, in-store audits (n = 142), retailer interviews (n = 78), and expert interviews (n = 10) of cannabis industry stakeholders. States were classified into three types of cannabis legalization status. Results: State-level THC market size was substantial, accounting for ≥90% of the combined cannabis market value of THC and CBD, regardless of legalization status. However, the composition of THC markets-across legal recreational, medical, illicit, and hemp-derived segments-varied considerably, even among states with the same legalization status. Conclusions: The emergence of hemp-derived THC in both legal and non-legal markets alongside the persistence of illicit THC sales in legal markets highlight regulatory gaps and challenges in market oversight. These findings underscore the need for integrated policy approaches that align enforcement strategies with public health objectives and consumer education.