The Science Behind THC Caps Is Inadequate, Says Epidemiologist Dr. M-J Milloy
As the popularity of cannabis grows, so too does the call for limiting tetrahydrocannabinol (THC). THC is the only cannabinoid with any intoxicating punch, and it’s long been demonized as risky, if not outright dangerous. Because of these long-standing assumptions, some are calling for THC caps as a means to reduce this risk.
There are already specific limits on THC in Canada: 10 milligrams per edible package and 1000 milligrams per extract package. States like California and Colorado have similar per-package limits (although typically much higher). But, in Vermont’s soon-to-open adult-use market, there will be a potency cap on the THC in flower. Florida, New York, and even federal regulations may follow suit.
Is THC truly dangerous, though? And if so, will any of the current or proposed restrictions work for their intended purpose?
Dr. M-J Milloy, PhD, Research Scientist at the British Columbia Centre on Substance Use (BCCSU) and an assistant professor in the Department of Medicine at the University of British Columbia (UBC), has a few opinions on both the current and proposed THC caps.
In a recent interview with Cannabis Health, he talked about the inadequate and insufficient science behind these policies and the real risk of these regulations backfiring.
The Argument For THC Caps
In most debates about limits on THC, there are two main arguments. The first is that cannabis has gotten stronger over the last few decades. The second is that higher levels of THC put the public at greater risk.
It is now well-established that the potency of cannabis has dramatically increased in the last 50 years. A paper titled, “New trends in cannabis potency in USA and Europe during the last decade (2008–2017),” published in 2019, measured a rise of 8.2 percent in just this 10-year period. The authors also noted a shift in the THC:CBD ratio, which is increasingly favouring more THC.
What’s more, the market is chock full of new extracts, isolates, and distillations that can reach upwards of 95 percent purity. As a result, consumers now have access to incredibly potent and intoxicating products, which didn’t exist 20 years ago.
This is much the same trend that has happened among other substances over the last few decades. From Milloy’s perspective, “Capitalism seems to always convert very safe plant-based products into much more concentrated and much more dangerous products. So you go from opium which is relatively benign, to heroin.”
With more THC packed into each puff, dab, or nibble, some regulators argue there is a greater risk to the public. As the 2019 report explained, “Increases in cannabis potency could, therefore, have important implications for the health effects of cannabis use, especially among adolescents who may be more vulnerable to cannabis harms.”
THC Caps Are Arbitrary, Not Backed by Science
Milloy confirms there have been rising rates of THC over the years. As he explained, “In terms of acute effects of cannabis, the more THC you have, the less cannabis you have to use to get those effects.”
In practical terms, this impacts consumers. There is a big difference in effects between a low and high THC product. Milloy spelled out one of the most telling examples: “Look at something with 25 percent THC. It’s qualitatively different than doing a dab of something which is approaching 100 percent crystalline THC.”
If cannabis and its various extractions now contain more THC, does this make it more dangerous? It’s here that Milloy’s opinion starts to deviate from that of regulators seeking to set strict THC caps.
As an epidemiologist, he finds there is very limited research about the dangers of THC. In his examination of the often-cited studies touted by policymakers, “the reality is, very little of it has been properly and systematically investigated through epidemiological research.”
There are a handful of studies about the risks of THC, including those covering adolescent exposure, but he calls these “very poor and very superficial.” He is resolute that “in terms of the link between THC and more long term effects? There is no good evidence out there.”
Any limits on THC per serving/package or THC percentage in flower are therefore completely arbitrary. There is not enough robust, well-controlled research to support the 10 percent cap on flower proposed in Florida, the 30 percent rule in Vermont, or even the 10 milligram per edible rule in Canada.
This doesn’t disagree with the fact that the effects of cannabinoids, and especially THC, are highly variable. From one person to the next, THC can trigger vastly different experiences. But, in Milloy’s opinion, this is why much more study is required before the debate is settled on THC’s risk profile.
More than ever, there is an impetus to investigate cannabis, to figure out real numbers and scientifically proven effects.
Why THC Caps Will Backfire
The quest to set THC caps is sold as a regulatory means to protect consumers from ever-increasing levels of THC. But, Milloy and other experts believe this approach will ultimately backfire. Limiting the availability of certain cannabis products will mean more consumers turn back to the black market to find the options they like.
In a recent interview for Forbes, Justin Strekal, from the Organization for the Reform of Marijuana Laws (NORML), stated, “Recriminalizing cannabis via THC caps will simply push the existing consumer base from the legal market to seek out similar products in the unregulated illicit market.”
Milloy confirms that THC caps are “already setting the regulated market up to fail if people can’t get the product they want.” The black market tends to pick up the slack when the legal market fails to meet consumer demand.
Unlicensed retailers in Canada are doing this already — selling edibles with extraordinary levels of THC. One quick Google search and it’s easy to find online ‘dispensaries’ selling edibles containing as much as 1000 milligrams per piece, much higher than what’s allowed under federal law.
Many Canadians continue to purchase cannabis via illicit channels because it’s more affordable. Reports by The Guardian and CBC highlight consumer sentiment about ‘government weed,’ mainly that it’s “garbage” and much too expensive, especially for patients with chronic conditions.
According to a 2019 survey commissioned by the Arthritis Society, Canadians for Fair Access to Medical Marijuana (CFAMM), and the Canadian Pharmacists Association (CPhA), 37 percent of respondents continue to purchase via the illicit market. Accessibility and costs are among the top reasons cited for buying from illegal sources.
Janet Yale, Arthritis Society President and CEO, is adamant that “it’s time the health system treat [cannabis] as medicine – and that starts with ensuring that patients have timely, reliable and affordable access to the strains, forms and concentrations they need, and that they have the guidance of a health care professional throughout the process.”
Restricting access to high-potency products increases the immediate costs for patients who require higher doses. THC caps will not encourage patients and recreational consumers to head to government stores. Milloy and others believe it will have the exact opposite effect — driving more traffic to the illicit market producers fulfilling the market need.
More Research, Not THC Limits, the Answer to Keeping Consumers Safe
The debate around THC limits boils down to the ongoing need for continued and rigorous study of this intoxicating cannabinoid.
We already know that the effects of THC are highly variable. This means, for some people, there may be long-term effects. But as Milloy points out, what these effects are, how many people they impact, and what the outside influencing factors may be are by no means clear.
Before regulators introduce arbitrary limits on THC per package, or worse, THC percentages in flower, there is an urgent and imperative need for a much better understanding of this cannabinoid. Otherwise, lawmakers risk a return to the illicit market.