Eye-Opening Results: Off-The-Shelf THC Percentage Testing in CA Market

California’s cannabis market is one of the most storied. It’s no surprise that some of those tales include cannabis testing fraud. There have been many recent stories and even studies done around California’s testing issues. I thought a small scale off-the-shelf potency test would be compelling, and help to demonstrate what the issues realistically look like. I know that some are hesitant to believe direct retests by laboratories, and I hoped that a third party could help lend an eye to the situation.

When I first pondered potency inflation, I felt the most obvious approach to detecting it would be to take a sample off the shelf to some labs and see what I found out. I wrote about doing that very thing in Oregon

It seems straightforward, right? 

Not exactly, but we’ll save the nuances for another post. This time, let’s focus on the exciting part – the results!

Results of the Three Sample Test In California

Experiment Design

The three samples were all pre-packaged, non-infused, pre-rolls in shrink wrap and light-resistant packaging bought from legal dispensaries in the Los Angeles area. Infused pre-rolls provide more eye-popping potency numbers, but the way they do that is by including potency-enhancing products. Non-infused pre-rolls mean the products were just made of cannabis flower, which reduces the risk of homogeneity issues when re-sampling in the lab. Each lab received roughly 10 grams of each sample to run a full compliance test. 

The samples were also all products that either linked to their original COA or listed the lab that conducted the original tests who was willing to confirm the accuracy of the tests for the THC potency results. It was important to have the original results to compare to. This requirement proved to really limit the selection, as California doesn’t require any COA information to be shared on retail packaging. There’s a genuine question of selection bias – wouldn’t the brands who list the testing information willingly also be the ones less likely to cheat? Perhaps that makes these results all the more shocking. 

In 2 out of the 3 cases, we were able to obtain products that had full CoA’s. This greatly limits understanding of the cannabinoid percentages. The issue is that this presents a reduction in granularity in our overall dataset, but is representative of the consumer experience, as it was difficult to get even this much information. 

Total THC as it appears on labels is a calculated value. △9-THC (delta-9 THC) is the psychoactive form of THC, and it’s available in the plant in small amounts. What is available in larger amounts is THCa, which is ‘tetrahydrocannabinolic acid.’ This acid is converted into △9-THC through heating, but with a loss of 12.3% in this conversion.  Thus, the formula to represent the entire theoretical amount of △9-THC in a cannabis product is (delta-9- THC%) + (THCA% x 0.877).

THC Design ‘Crescendo’ Sativa Pre-Rolls

These prerolls were the most limited in available information. The THC Design Crescendo pre-rolls were tested by Encore. While there’s no COA, the accuracy is confirmed by Encore over email. Total THC is listed as 34.18%, and they were packaged on 2/14/2023. These measurements were taken using dry weight. Our first lab retested these at 24.06% THC, and the other retested at 25.48% THC (34% and 32% overstatement, respectively). These retests fall far outside of California’s 10% threshold. Even more troubling is the fact that at one of the labs, the pre-rolls also failed an Aspergillus test.

Glasshouse Garlic Starship Pre-Rolls

These pre-rolls were originally tested by BelCosta (COA). Their labeled total THC is listed as 25.1%, and they were packaged on 7/14/22. These measurements were taken using dry weight. One lab retested the sample as having 21.55% THC, and the other retested them at 22.19% THC, representing a difference of 16% or 13% – which is outside of California’s 10% threshold.

Old Pal Tiki Punch Pre-Rolls

Originally tested by Excelbis (COA). Their total THC is listed as 27.5327%, and they were packaged on 7/26/2022. These measurements were taken using dry weight. One lab retested the sample as having 15.4% THC, and the other test indicated 17.58% THC. The difference between the label demonstrated 78% or 56%, respectively. Both of these are very, very much outside of California’s 10% threshold.

Built on the Shoulders of Giants: The Study Done by 2 Labs in CA

This three sample run hasn’t been the only sort of work of this type conducted in California. One of the labs that tested for us, Anresco, was involved in a study that included 150 samples in California.

For this study, several labs across California were frustrated with the current climate of lab testing and decided to participate in this study. Their results demonstrated that 87% of cannabis products they tested overstated THC on the label by more than 10%, and around half of them overstated THC on the label by more than 20%.

Why Off-the-Shelf Testing is Effective

I’ve explored the importance of off-the-shelf testing as one of many vital components to a healthy cannabis regulatory environment. Testing THC potency off-the-shelf and publishing the results helps to demonstrate the importance of off-the-shelf testing for regulators. It’s vital that these tests be run by an organization without economic incentives. 

Why These Studies Are Limited

We’ve already demonstrated the weaknesses of proficiency testing that isn’t run blind, and these sorts of tests can only yield so much information on this scale. While information from laboratories checking products in their markets is interesting and allows them to use their resources to support these efforts, there can be economic motivation behind them doing so. 

The states need to be the ones fulfilling this role to keep the market in check. There are a variety of ways that states can support similar audit efforts, whether the regulators see fit to (1) work with legislators to establish reference labs, (2) leverage labs at their Department of Agriculture, or (3) run multi-sample proficiency tests using off-the-shelf cannabis. But it’s also important that there are disciplinary actions built into regulations that allow for penalizing those who engage in THC potency inflation, and give mechanisms to remove overstated products from shelves. 

Otherwise all of this testing would be for nothing.

What Does This Mean for Consumers?

These results confirm that California consumers are probably overpaying for cannabis products due to incorrect information on the label. None of the products tested met the state’s standard for being within range of THC potency on the label. 

I’ve heard a lot of people say ‘who cares if stoners don’t get as high,’ but that’s not what this is really about. It’s about consumers being misled by producers, labs, and retailers.  

My personal interest in all of this started with a couple of things – as a cannabis patient I was trying to understand what it was about cannabis that helped address my migraines and my mental health struggles with a form of PTSD known as ‘complex PTSD.’ I started journaling about cannabis trying to figure out what terpenes and cannabinoids gave me relief, and I found quickly that the information on the label was often not enough to give a complete picture. I then started to discover that in some instances, the information was even unreliable. There are many other medical patients out there like me, whose pain was used to create the cannabis industry, who are now being misled about the medicine they helped to make legal.

I also don’t want to under-state the result that one of the pre-rolls failed for Aspergillus Flavus in the retest. It’s yet another demonstration of just how important it is for state regulators to tighten cannabis lab regulations and audit procedures.

Further Reading

The Inflated THC Crisis Plaguing California Cannabis

California’s $11 million cannabis lab is off to a rocky start

What’s The Matter With California Cannabis?

Let’s Learn About Cannabis Storage!