Millions of Americans use cannabis in moderation each month without any problems. However, evidence is mounting of harmful physical and mental health effects associated with heavy or long-term regular cannabis use. At the same time, existing legal markets in the United States are making high-potency cannabis products available to adult consumers. Recent international recommendations suggest that governments adopt market regulations that promote responsible use. Federal policymakers in the U.S. are debating liberalizing cannabis policy and looking to states and nations with existing recreational cannabis laws as examples. Amid this debate, it is important to examine the extent to which regulations within various jurisdictions promote responsible use and protect public health. We review elements of cannabis legalization policies across U.S. states, Canada and Uruguay that research suggests could be important for promoting responsible use. Specific policy areas considered include: capping the amount of delta-9-tetrahydrocannabinol (THC) in all products, instituting sales limits, taxing cannabis based on potency of THC and implementing seed-to-sale tracking systems. We find that current regulations of legal cannabis markets are weaker in the U.S. compared to Canada and Uruguay in terms of preventing harmful use across these dimensions. Federal policymakers should understand the strengths and limitations of existing U.S. state policies and consider public health regulations being adopted abroad when developing federal cannabis regulations.

Key takeaways:

• Long-term or heavy use of cannabis—in particular, high-potency manufactured cannabis products—is associated with negative health outcomes, including psychosis, cannabis hyperemesis and addiction.
• Vermont and Connecticut are the only states that cap potency of THC on most types of cannabis products sold, despite this being a useful tool to prevent harmful consumption.
• Assuming a standardized dose of 10 milligrams of THC for average-potency cannabis products, all states allow purchases exceeding 500 doses. Current sales restrictions do not promote moderation in use.
• Taxes based on potency, rather than price or weight, do a better job of incentivizing moderate THC consumption.
• A single, federal, seed-to-sale tracking system will assist with enforcement of all policies and aid in public health research, particularly given the restrictions in place on scientific inquiry of these products.