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INSIGHTS BLOG > Arguments For and Against Caps on THC Potency

Arguments For and Against Caps on THC Potency

Written on 15 March 2022

Ruth Fisher, PhD. by Ruth Fisher, PhD



Selective breeding has led to significant increases in the potency of cannabis flower over time. The NIH reports that the potency of cannabis seized by the DEA increased from less than 4% in 1995 to over 14% in 2019 (see Figure 1).


Figure 1

Percentage THC CBD cannabis samples seized by DEA



Especially in less mature markets, recreational users tend to focus on THC content when choosing which products to buy, where “flower that tests at 25% THC or higher flies off the shelves.”[1] Cannabis concentrates are also widely available at 70% - 90% THC.[2]

The increasing availability of high potency cannabis products has created no small amount of alarm. In response, many states have considered proposals to cap THC potency in cannabis products (CA, CO, FL, IL, MA, MS, MT, NY, VA, VT, WA). This analysis seeks to summarize the arguments for and against imposing caps on THC potency. 

Arguments in Favor of Caps on THC

Advocates of capping THC content on cannabis products generally present some combination of two arguments:

  1. The potency in cannabis flower and cannabis products has been increasing over time. Higher potency products are associated with:[3]
  • Greater risks of causing adverse effects, including psychotic symptoms in users,
  • Greater risks of addiction,
  • Greater risks of psychosis in users with such predispositions, and
  • Increasing numbers of cannabis-related ER visits and hospitalizations.
  1. There’s great concern that kids and young adults will have access to ever more potent products.[4]

A third point has also been raised:

  1. There's no credible research showing that there’s medicinal value of THC in concentrations over 10%, and caps on THC would protect unwitting consumers from ingesting highly potent products without significantly infringing on the rights of marijuana enthusiasts.[5]


Arguments Against Caps on THC

The opponents of capping THC content on cannabis products present arguments against caps that generally fall into one of five categories: arguments in favor of caps on THC are flawed, arguments in favor of caps on THC are misplaced, caps on THC are bad, caps on THC won’t work, and high content THC products are beneficial.


Arguments for Caps on THC Are Flawed

Opponents of capping THC content on cannabis products indicate that the arguments offered in support of THC caps are flawed.

Studies Indicating Risks of High THC Products Are Flawed: Proponents of caps on THC potency cite studies showing that people who consume large amounts of THC are more likely to experience adverse health effects. Opponents of caps on THC content argue that the cited studies are flawed because the studies’ conclusions confuse causation with correlation. That is, studies have shown that “young people who misuse cannabis” also have elevated risk for self-harm or psychosis. Yet, the studies don’t establish that THC caused users to engage in self-harm or suffer from psychosis. It could just as easily be the case that young people who engage in self-harm or suffer from psychosis use cannabis as a means of self-medication.[6] Also, antagonists of THC caps further argue that the FDA/NIH has not conducted studies on the long-term effects of high THC potency products.[7] One could further argue that people who want to consume large amounts of THC don’t need high potency products to do so; they can just as easily consume larger quantities of lower potency products.


Arguments for Caps on THC Are Misplaced

Opponents of capping THC content on cannabis products indicate that the arguments offered in support of THC caps are misplaced.

High THC Products Are Not New: Proponents of caps on THC potency indicate that high THC products are a new phenomenon causing new and unexpected problems.[8] Yet, high THC products are not, in fact, new. Rather, high potency medical tinctures were available from the mid-1800s until they were banned under the 1937 Marijuana Tax Act, and potent hash and hash oil products have also been around for hundreds of years or more.[9]

Consistency and Transparency Are More Important Than Potency: “One of the great hindrances to the wider use of this drug is the great variability in the potency of different samples of cannabis which renders it impossible to approximate the proper dose of any individual sample except by clinical trial.”[10] What’s needed is not a cap on potency, but rather consistency and transparency (labeling) in potency from one batch to the next so consumers can accurately and appropriately titrate their doses.

Demand for High THC Products Decreases as Markets Mature: Newer cannabis markets tend to experience greater demand for high THC products. As markets mature, however, consumers tend to transition away from focusing solely on THC to appreciating the experiences that a diversity of cannabis compounds have to offer. Demand for high content THC products should thus decrease over time on their own as markets mature.[11]


Caps on THC Are Bad

Opponents of capping THC content on cannabis products provide several arguments as to why caps are a bad thing.

THC Caps Are a Slippery Slope: Caps on THC content are arbitrary in nature and they serve as a slippery slope: “It’s prohibitionism 2.0. Once they start putting caps on that, what don’t they put caps on?”[12]

THC Caps Increase Costs for Medical Patients: Imposing caps on THC content will result in medical users paying higher prices to achieve the THC levels they need.[13]

THC Caps Push Consumers to Black Markets and Bankrupt Legal Businesses: If legal markets don’t supply high content THC products, many consumers will switch to Black Market suppliers who do supply these products. If too many consumers transition out of legal markets and into Black Markets, legal market businesses will close. Since Black Markets suppliers do not adhere to safety protocols (e.g., product testing and safety of additives), consumers face greater health and safety risks from using Black Market products.[14]


Caps on THC Won’t Work

Opponents of capping THC content on cannabis products provide several arguments as to why caps won’t reduce the amount of THC users consume.

THC Caps Won’t Restrict Access by Children: One of the most common arguments in favor of caps is that they will decrease children’s access to THC. Opponents of caps insist that children have easy access to cannabis whether or not THC content is capped.[15]  In fact, cannabis usage patterns by children have remain virtually unchanged over the past 25 years, independent of legality or potency (see Figure 2).[16]


Figure 2

hs use

Source:, p.18


Personally, I find the argument that banning high potency products will reduce access by children baffling. Children are not legally able to purchase cannabis products – high THC content or otherwise – on their own. To the extent that they use these products, they either get them illegally (i.e., on the Black Market or from friends) or from adults (i.e., parents). If kids already get these products illegally, then banning currently legal products won’t decrease kids’ access, but will only deprive legal adults from being able to access them. If, on the other hand, kids are using cannabis products from adults, then any associated harm is an issue of parental negligence, not a matter of lack of appropriate regulation.

With Lower THC Content, People Simply Use More: Consumers titrate their doses to consume the amount of THC they want. If products contain more THC, users will consume less product. Conversely, if products contain less THC, then users will simply consume more product.[17]

Cap on %THC ≠ Low THC mg: Most proposals for caps on THC limit the percentage of THC in flower and/or other cannabis products. Yet, products with low concentrations can still yield  high THC content if users consume enough of the product. [18] For example, a gram (1,000 mg) pre-roll with flower with low THC potency of 10% still contains 100 mg of THC, which is a substantial amount.

Caps Are Difficult to Enact and Usually Not Enforced: Once cannabis markets have been established, it’s difficult to enact THC caps, because there’s a lot of resistance to such policies. Also, “Policies governing THC potency caps, while usually lacking in bipartisan support, also have a history of not being enforced when the bills are passed.” And finally, such laws pull law enforcement agencies back into the role of having to enforce cannabis laws.[19]


High THC Content Is Good

Opponents of capping THC content on cannabis products note that there are advantages of high THC products that will be lost if THC caps are implemented.

With High THC Products, Consume Less: By using higher potency products, consumers — and especially medical consumers who need high doses of THC to address their conditions —  use less product. Smoking less flower is healthier for users’ lungs, while consuming less concentrate means users ingest less filler. To the extent that fillers may contain unhealthy additives (e.g., vitamin E acetate, sugar, carrier oils), consuming less fillers is healthier and/or less risky.[20]

High THC Products Enable Easy and More Reliable Dosing: Higher potency products provide a greater ease of reaching one’s preferred dose and greater reliability in dosing.[21]