Are THC potency caps a move toward marijuana prohibition?

With many consumers demanding high-potency cannabis, a debate is swirling over whether states where marijuana is regulated should implement caps on THC content in flower, concentrates and edibles.

While many states regulate the amount of marijuana products that can be purchased, few impose direct caps on the THC potency of the products themselves, particularly for cannabis flower.

States with specific THC potency caps for certain product types include:

• Connecticut and Vermont, which have 30% caps on flower and 60% caps on concentrates.
• Massachusetts, which doesn’t limit THC content for flower but restricts concentrates to 70% and edibles to 5.5 milligrams per serving.
• Oregon, which doesn’t have a limit on flower but caps concentrates at 2,000 milligrams per package and edibles at 10 milligrams of THC per serving and 100 milligrams per package.

David Hammond, a researcher at the University of Waterloo in Ontario, said Canada’s model for edibles, which sets a limit of 10 milligram of THC per package, prevents consumers from ingesting too much.

“Consumers in Canada – not public health folks, but the people who use it – are supportive of THC limits on edibles,” Hammond told MJBizDaily.

But the discussion around potency is more nuanced when considering different product types.

While a 30% THC cap is often suggested, Hammond said it’s irrelevant for cannabis flower, which rarely, if ever, exceeds that percentage.

The main impact of caps falls on vaping liquids, which can range from 70% to 90% THC, and wax or shatter also will have high concentrations of the cannabis plant’s psychoactive ingredient.

“The problem is that our concept of what high THC is really differs across products,” Hammond said.

THC caps could be a move toward prohibition

Dr. Byron Adinoff, president of Doctors for Drug Policy Reform in Denver, said he has reservations about THC caps, arguing that they risk pushing the market back toward prohibition.

“As soon as you get into saying we’re capping it, anything above the cap is illegal,” Adinoff said, raising concerns about penalties and the potential for a new illicit market.

Adinoff points to Colorado’s proposal a few years ago for a 15% cap, which he said would have wiped out 90% of the industry and sent marijuana back to prohibition.

Adinoff also questions the scientific basis for cap proposals, noting the variability in high-potency studies and lack of conclusive research on what constitutes a good level for caps.

Steve Rolles, a senior policy analyst for the United Kingdom-based Transform Drug Policy Foundation, said that if high-potency products are associated with greater risks, policies should strive to discourage their use or encourage lower-potency alternatives.

The faster onset of high-potency products could lead to more compulsive use and dependency, making THC content a reasonable target for regulation, Rolles said.

“There should be a specific goal of education – warnings on packaging, special training for vendors – that acknowledges the increased risks of high-potency products and provides guidance about how to manage those risks,” he said.

“It’s not about curtailing people’s choice.”

‘Would you be guillotined at dawn?’

Strategies to regulate marijuana potency range from THC caps on certain products to higher taxes for more potent products.

Setting a higher-age threshold, such as 25, for access to stronger products is another alternative.

Rolles said it’s challenging to grow and test cannabis plants to precisely calibrate THC content.

“If you did sell something that was 28% and there was a 25% limit, what would happen? Would it be confiscated? Would you go to jail? Would you be guillotined at dawn? Would you lose your license?” Rolles said.

“The main problem with caps is if you put a cap on THC and there is established demand, you’ll create a parallel illegal market.

“That’s sort of defeating the purpose. You have to meet the market where it’s at.

“Once you’re there, you can use tools like progressive tax increases.”

Margaret Jackson can be reached at margaret.jackson@mjbizdaily.com.