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Monday May 17, 2021

By Erin Hiatt


Victories for cannabis legalization keep rolling in. Lawmakers in New York just recently ironed out the final details of what is poised to be one of the largest markets in the country and a potential $4.2 billion dollar industry. The new law will allow for adults 21 and older to buy and possess up to 3 ounces of cannabis. This is all pretty standard fare – cannabis markets across the country have been essentially following the alcohol laws, where you have to be 21 or older to purchase or consume alcohol.

But on the North American continent, the U.S. seems to be going it alone on the age of 21. Canada – who has had a legal cannabis market since 2018 – allows adults 18 and older to possess and consume cannabis (though it does vary by province, be sure to check local laws). A similar plan is unfolding in Mexico, whose lawmakers are in the final stages of legalizing cannabis in the country.

It begs the question; is there any particular reason that lawmakers have chosen 21 as the legal age of cannabis consumption in the U.S.? What age should it be?

Why Is 21 the Age Limit for Smoking Cannabis?

The most concise explanation may point to reasons both convenient and backed by science. The legal age for tobacco and alcohol consumption in the U.S., for the most part, is 21 years old, making it easy to slot adult-use cannabis into the same category. The history of why the US drinking age limit is 21 is somewhat complicated but seems to boil down to a holdover from an old English common law, combined with a backlash against drunk driving.

In general, setting the age limit for consumption to be after the bulk of teenage development is finished is scientifically sound, as the brain doesn’t fully develop until age 25 (a magic number you may recognize as the year when auto insurance drops in price, and this is no coincidence). However, the exact age at which cannabis might harm this development is a more complex matter. In recent scientific research, a 2020 study looking at Canadian cannabis consumers found that the age of 21 could be overly restrictive. Instead, researchers settled at the age of 19, when negative long-term mental and physical health impact of the plants appear to be minimized.

A young women drinking a beer
The main reason the legal age to smoke cannabis in the U.S. is 21 is in order to align it with the drinking age. photo credit

In practice, there is a delicate balance to discerning the earliest safe age of entry for cannabis consumption, including the measuring of potential long term health outcomes, educational outcomes, and the risks of pushing under-age consumers into an unsafe and unregulated illicit market.

For the Canadian study, researchers evaluated survey data from 20,000 consumers between the ages of 21 and 65 and measured key markers of their lives, including general health, mental health, and educational attainment. Below are a few takeaways.

Data from Marijuana Age-Limit Studies:

  • Respondents reported better health if they started consuming at 18 or older
  • They reported better mental health if they started consuming after age 19
  • Those who started smoking after 21 had attained more education than those who began before the age of 21
  • Scientists settled at the age of 19 because there were no significant health differences between those who began cannabis consumption at 19 and those that started at 21

While this particular study evaluated the earliest age of entry for cannabis consumption, as legal access to cannabis consumption broadens, some doctors and researchers are beginning to wonder if there should be a ceiling on consumption age as well. 

Cannabis Consumption Among Seniors

A late 2020 study published in the Annals of Internal Medicine looked at three years of survey data on 171,507 U.S. adults ages 55 and older from 19 states and two territories. The research found that older Americans – especially men – were consuming cannabis at much higher rates in the age of legalization.

Of those who reported using cannabis in the past thirty days, men ages 60-64 are leading the way, with consumption rising from 8.9% in 2016 to 12.6% in 2018. Over the same time period, consumption among men ages 65-69 rose from 4.3% to 8.2%, and for men 70-74, from 3.2% to 6%. There was little change in consumption habits among older women.

An older man smoking a bowl out of a bong
There has been an increase in cannabis consumption from the older generations of men, specifically. photo credit

While the survey didn’t evaluate why there was an increase in consumption among older Americans, researchers offer a few possibilities, including increased availability, more willingness to use the plant for conditions like pain, anxiety, and sleep disorders due to wide reporting of anecdotal claims of medicinal benefits, and less stigma around its consumption. There is some early scientific evidence as well. THC has shown an ability to restore some cognitive functions in older mice, as reported by Scientific American.

Overall, we still have limited information on how cannabis affects older adults, especially those who take more medications for health conditions than younger people. So far, there is very little research that would help older consumers find the right strain for their condition, or understand how cannabis may interact with any medications. 

Final Thoughts

To date, there is insufficient evidence to determine a hard age limit on cannabis consumption, both for a lower and upper limit. It appears that the research supports “sometime after the age of 19” as a better starting point than before it, however drawing further conclusions get a little more complex. Older individuals may get some amount of benefit to their cognition, but the large amount of variables relevant to senior health make any specific determinations difficult without more study. However, this lack of research once again invites consumers to have candid conversations with their healthcare professional before consuming cannabis for any condition, regardless of age.

What do you think the age limit for marijuana should be? Share your opinion in the comments!

Photo Credit: FatCamera (license)


Erin Hiatt Erin Hiatt

Erin Hiatt is a New York City-based writer who has been covering the cannabis industry for more than six years. Her work - which has appeared in Hemp Connoisseur Magazine, PotGuide, Civilized, Vice, Freedom Leaf, MERRY JANE, Alternet, and CannaInvestor - covers a broad range of topics, including cannabis policy and law, CBD, hemp law and applications, science and technology, beauty, and psychedelics.

Erin's work and industry insights have been featured on the podcasts The Let's Go Eat Show, In the Know 420, and she has appeared as a featured panelist on the topic of hemp media. Erin has interviewed top industry experts such as Dr. Carl Hart, Ethan Nadelmann, Amanda Feilding, Mark A.R. Kleiman, Dr. James Fadiman, and culture icons Governor Jesse Ventura, and author Tom Robbins. You can follow her work on LinkedInWordpress, @erinhiatt on Twitter, and @erinisred on Instagram.

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