By the numbers: In the 1990s, 5% THC cannabis was some of the strongest you could find.

• Today, "it's very difficult to find cannabis that's less than 20% THC" in a Los Angeles dispensary, says Ziva Cooper, director of the UCLA Center for Cannabis and Cannabinoids.
• According to National Institute of Drug Abuse data, cannabis samples seized in 1995 averaged less than 4% THC. In 2022, they averaged more than 16%.
• The percentage has only increased since, experts say.

It's a common misconception that the highest high is the best high, "but that's bogus," Martin Lee, director of nonprofit Project CBD and author of "Smoke Signals: A Social History of Marijuana," tells Axios. "That's not the way to judge the plant."

And THC levels aren't limited to what can be produced by the highest-THC cannabis plant.

• "You're taking the plant out of the equation at this point," Cooper tells Axios, because manufacturers can extract THC to make superficially potent products, like THC-infused prerolls and dabs.

Zoom in: Older adults — who favor cannabis edibles — are inadvertently eating too much THC.

• A study in California found a 1,808% relative increase in the rate of cannabis-related trips to the ER among adults 65 and older from 2005 to 2019. The state legalized medical marijuana in 1996 and recreational cannabis in 2016.

• And a study of senior citizens in Canada suggests ER rates for cannabis poisoning increased after cannabis flower was legalized in 2018, and increased even more after edibles were legalized in 2020.

Bottom line: These high-potency products available in dispensaries haven't been tested for safety. "It is very concerning," says Cooper, who co-authored a research paper on the issue last month.

More from Axios:

• Trying cannabis? Read this before you do
• Where marijuana is legal and for what use
• Hemp-derived THC: The "junk food" of cannabis?