The structural factors that may contribute to substance use among MSM remain largely unexplored and under-researched. This is concerning because addressing these factors to improve MSM health overall may have a larger population-level impact than individual interventions [
83]. Certainly, legalizing syringe exchange and making clean supplies available to injectors can be expected to benefit the SUMSM who inject [
84]. However, it is unclear what other policies, laws, or social forces contribute to the high prevalence of non-injection substance use and related harms, including sexual risk, among MSM. Substance use is a largely criminalized and stigmatized practice. Evidence shows limited success from prohibitive approaches to drug control. For example, precursor regulation for methamphetamine production had mixed and mostly short-term effects on the supply and purity of the drug [
5,
85]. Decriminalization may reduce substance use-related harms [
86‐
88]. “Wars on drugs” are expensive, have little or no apparent effect, and in some cases have led to catastrophic casualties and egregious human rights violations [
5,
86,
89]. In recognition of these failures, The Vienna Declaration, released at the XVIII International AIDS Conference, calls for reorienting drug policies toward those that are evidence-based [
86].