From seed to sale, the cannabis industry has experienced a rapid evolution in the past decade. Gone are the days of clandestine cultivation and covert dealing. In its place, we see a legitimate, thriving industry that is becoming increasingly integrated into mainstream commerce.

As of July 2022, 37 states in the U.S. have passed legislation allowing its medical use, 19 of which also allow legal recreational use of marijuana for adults. In 2020, legal cannabis sales surged past $21 billion, up nearly 50% from 2019.

However, with great power comes great responsibility, and legal cannabis must adhere to the same standards as other legal products. One of the most important aspects of this is the accurate reporting of THC content in cannabis products.

But, if the findings of a new study that appeared this week in PLOS ONE are any indication, cannabis retailers and distributors are doing a pretty poor job at this, as researchers found the overwhelming majority of cannabis samples they analyzed had significantly less THC than advertised. In some situations, we can suspect this is by design at the expense of the duped consumer.

“THC potency for flower products provided at dispensaries is much lower than advertised and reported on the labels,” Anna Schwabe, a cannabis researcher and geneticist at the University of Northern Colorado, told ZME Science.

It all started when Schwabe noticed that many of the cannabis flower samples she had purchased for a different study of cannabinoids and terpenes (the aromatic compounds that determine the smell of cannabis) had much lower THC than the packaging advertised.

“We decided to expand the study by purchasing more flowers (high THC, low THC, and everything in between) from dispensaries all over the front range in order to capture a range of growers, distributors, and testing labs,” she said.

Cautionary Tale: Buyer Beware

While cannabis is more popular than ever, the herb is still a Schedule I substance, making it illegal at the federal level. This means obtaining funding is almost nigh impossible from public funds.

So the researchers rolled up their sleeves and embarked on an epic trip across the state visiting many dispensaries. But since they had to buy the samples out of their own money, the study was limited to just 23 samples obtained from 10 dispensaries throughout the Colorado Front Range.

The samples were tested at Mile High Labs in Colorado, where researchers learned that the average THC content was around 23% lower than the lowest range reported on the product label, and as much as 35% lower than the highest range advertised on the packaging. Overall, 70% of the samples were more than 15% lower than the THC content reported on the label.

Long story short, it seems like most consumers are paying more for products with lower THC potency values than expected. This is an industry-wide problem since the error was found in products from many different dispensaries.

As a result, consumers who rely on accurate THC potency information to make informed decisions about their cannabis consumption may be at risk of overpaying for products with inflated potency values. Additionally, those who consume cannabis for medicinal purposes may not be receiving the intended therapeutic effects if they are consuming products with lower-than-reported THC levels.

“I like to think of this as a cautionary tale, buyer beware- you are not getting what you think you are getting,” Schwabe said.

The Blame Game: Who is Responsible for Inflated THC Numbers?

THC is most widely tested using a method called High-Performance Liquid Chromatography (HPLC), which separates and measures the content of the dozens of cannabinoids found in marijuana flowers. However, there is no single standard testing protocol and there is no legal incentive for testing labs to do their best due diligence.

“Methods can also be adjusted a number of ways to give “better” or higher numbers, which is what some of the labs might be doing,” Schwabe told me.

Indeed at least one THC testing lab out of the twenty or so found in Colorado has been shut down due to falsifying numbers, which suggests doctoring THC values may be much more widespread than some people believe. The numbers can be inflated through either method manipulation or outright data fudging.

“Although I have not witnessed this firsthand, there is many a tale that labs will ask what they want their numbers to be, and amazingly they get those numbers,” the cannabis scientist added.

But the fault doesn’t lie in labs alone. Growers have a financial incentive to list products with the highest amount of THC because most people just think more THC equals a better product. So what often happens is that some growers might send an unrepresentative sample from their batch. For instance, they might send a sample of the apical bud, which is the flower that grows at the top of the plant and is higher in THC compared to the rest of the buds, even though they are all the same strain and even from the same plant.

“It is hard to pinpoint who is liable for the inflation, but recent stories suggest labs and distributors are both to blame. The lab for generating the results and the distributors for shopping around to labs that generate the highest numbers,” Schwabe said.

Although the researchers only looked at samples from Colorado, this issue doesn’t seem isolated to the state. There are ongoing lawsuits in Arkansas and California over allegations of dispensaries selling medical marijuana with inflated THC content on their label.

“This issue is widespread. There are court cases as people are now realizing they are not getting what they thought. Unfortunately, right now, the market is based largely on THC potency, and it is a vicious cycle,” Schwabe said.

Beyond THC: The Importance of Cannabis Quality

Until the market becomes more regulated with standard testing protocols, Schwabe cautions buyers to stop shopping for marijuana products looking for the highest THC content. There is more to cannabis quality than THC, just like what makes a good wine or beer is not the alcohol content. “Otherwise Everclear would be sold as top shelf!” she added.

On a more helpful note, I’ll leave you with Schwabe’s wisdom on how to shop cannabis — the right way:

“What makes a quality cannabis flower is so much more, not unlike quality wine or beer. Where and how it is grown, the genetic stock of the cultivar, the terpene profile, how the plants were dried and cured, how the product was stored, and time to sale all have the potential to impact quality.”

“Consumers should be able to judge the quality through other measures. In some dispensaries when deciding what to buy, appearance and smell are the immediate observable characteristics to judge quality. In some states, the product is pre-weighed and packaged so there is no way to personally judge quality prior to purchase. THC content and recommendations from a budtender might be the only source of information.”

“Dispensaries could use a better measure of what they put on the top shelf vs. bottom shelf products, perhaps based on full phytochemical profiles, an in-house assessment, or consumer feedback. This could remove consumers from perpetuating the cycle that THC is driving the market where currently everyone is incentivized to inflate the numbers in order to maximize profits. Unfortunately, it is the consumer on the short end of this stick- not getting what they paid for and being duped into thinking a single cannabinoid equates to quality and experience.”