Colorado researchers review health effects of high-potency pot products

By: - February 19, 2022 4:00 am
marijuana extracts

A variety of commercialized THC products in Colorado. From left: THC-infused brownie, THC-infused lollipop, 73% THC shatter, 22% THC bud, THC-infused coffee, 74% THC hash oil syringe, e-cigarette with THC, THC-infused breath mints. (THC Photos via Flickr/CC BY-ND 2.0)

Researchers have made “a great deal of progress” on reviewing available evidence of high-potency marijuana products’ health effects, the dean of the Colorado School of Public Health told state lawmakers Friday.

The scientific review is required under 2021 legislation, House Bill 21-1317, that sought to address concerns from parents about potential harms of edibles, wax, oil and other products that contain concentrated THC, the psychoactive molecule in marijuana.


To conduct its review, a team at the School of Public Health is first compiling data from existing evidence-based research into the effects of high-potency pot products. The team’s initial report is due July 1. HB-1317 provided $1 million per year for three years for the School of Public Health to complete the scientific review and then conduct additional research into areas where the review identifies knowledge gaps.

Dr. Jonathan Samet, dean of the Colorado School of Public Health, told lawmakers on the House Public and Behavioral Health and Human Services Committee that his team has started the process of collecting studies that examine the benefits and adverse effects of marijuana concentrates.

“We are bringing together, literally, the findings now from thousands of scientific publications,” Samet said.

Over the last six months, the research team has screened more than 46,000 scientific articles for potential inclusion in the review, and narrowed them down to about 5,000. Samet’s team has recruited at least 16 public health students so far to help with the project, he said.

Rep. Judy Amabile, a Boulder Democrat, asked whether in selecting studies for its review, the team was trying to balance the number of studies that looked into potential benefits of high-potency products with those that showed adverse effects. Samet said the goal was to capture all of the available information that met the team’s criteria. The School of Public Health is looking for evidence-based studies that examine the health outcomes for humans of using products with concentrated THC, according to the team’s published review protocol.

We are bringing together, literally, the findings now from thousands of scientific publications.

– Dr. Jonathan Samet, dean of the Colorado School of Public Health

“Just putting this information together and putting it into the form that is useful is an extraordinarily large task, and I think none of us knew how much information … until this review was started,” Samet said. The team anticipates meeting their July 1 deadline for the initial report.

The question of whether such a review would, or should, be focused on adverse effects was one contentious topic last legislative session, when industry advocates expressed concerns that the review could be biased, depending on the language in the final version of HB-1317.

The bipartisan bill was sponsored last year by House Speaker Alec Garnett, a Denver Democrat, and Rep. Yadira Caraveo, a Thornton Democrat, along with Sens. Chris Hansen, a Democrat from Denver, and Paul Lundeen, a Republican from Monument. Gov. Jared Polis, a Democrat, signed it into law in June.

Besides requiring the School of Public Health to complete a scientific review of the effects of high-potency marijuana products, HB-1317 put up new barriers to medical marijuana for young adults. While you must be at least 21 to purchase retail marijuana in Colorado, a medical marijuana card can be issued to adults ages 18 and older. HB-1317 required doctors recommending medical marijuana for 18- to 20-year-olds to do so through an in-person appointment. Doctors recommending marijuana for 18- to 20-year-olds now must review those patients’ mental health history — along with their medical history, which was already required — before recommending the substance. Those provisions of the new law don’t apply to young adults who had a medical marijuana card prior to turning 18.

The law also required all doctor recommendations for medical marijuana to include the maximum THC potency level, daily quantity and directions for use.


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Faith Miller
Faith Miller

Faith Miller was a reporter with Colorado Newsline covering the Colorado Legislature, immigration and other stories.