Unreliable Marijuana Labels: The Hidden Risks of Inaccurate Potency and Contaminant Information

Unreliable Marijuana Labels: The Hidden Risks of Inaccurate Potency and Contaminant Information

July 21, 2023

One of the main arguments in favor of legalizing recreational marijuana was to ensure consumers had access to tested, regulated products, and could trust the information on product labels. However, a recent investigation has revealed that the potency levels listed on marijuana product labels are often inflated, while some products also contain contaminants that could be unsafe for human consumption.

This means that marijuana consumers cannot confidently rely on product labels, as different labs use varying testing methods and technologies. In this article, we'll explore the concerning findings of the investigation and their implications for consumers.

Related article: Everything You Need to Know About Cannabis Product Labels

Testing Discrepancies and Lack of Standards

The recent findings raise concerns about the reliability of marijuana product labels. Different labs use various technologies and methods for testing, leading to inconsistent THC level readings. Some growers choose labs that report higher THC levels to attract customers, even if the testing methods may not be entirely accurate. This lack of standardized testing practices and oversight in the cannabis industry has created a somewhat chaotic and unregulated environment.

Massachusetts's Cannabis Control Commission, responsible for overseeing the recreational marijuana sector, has not taken decisive action to address these issues. While Commissioner Kimberly Roy has expressed interest in establishing an independent standards lab to set consistent testing benchmarks, there is currently a lack of clear regulations in place. Some industry officials believe that more stringent regulation is necessary to ensure integrity and safety within the cannabis industry. Without proper accountability and standardization, consumers and patients may not have confidence in the safety and accuracy of the products they are using.

The Secret Shopper Campaign

In November, researchers investigated marijuana sold at Blackstone Valley Cannabis in Uxbridge, Massachusetts, focusing on a strain called Bubba Kush known for its "skunky but fruity" high. The label claimed it contained 33.46% total cannabinoids and 32% THCa, which converts to the compound THC responsible for the high. However, testing at other labs revealed lower levels, about a third less than advertised, raising concerns about inaccurate labels.

The Bubba Kush was grown by Green Meadows Farm and tested by CDX Analytics (a Cannabis Testing Laboratory), which confirmed the label's THC percentages and passed required safety tests. Yet, other labs found discrepancies, leading to worries about product consistency. Other marijuana flower samples from different stores also showed lower THC potency than labeled, but the differences among labs' results were small.

Some samples, like Zebra Cake from Green N' Go and Mile 62 Butterstuff from MedMen, failed contaminant tests, exposing consumers to potential health risks. Scientist Jeff Rawson's tests had similar outcomes, showing lower THC levels than claimed on labels and identifying contaminants in some samples. These findings highlight the need for better regulation and standards in the cannabis industry to ensure consumer safety and accurate product information.

Testing Methods and Differences

Marijuana test results can change due to various reasons, and one explanation is the short shelf life of marijuana. Factors like storage temperature, container type, and exposure to light can affect its potency. Different labs may also report varying results because of unclear guidelines and lack of standardized testing methods.

Tests on different marijuana samples purchased from stores showed discrepancies in THC potency levels reported by different labs. There are disagreements among labs on how to calculate potency, especially concerning the moisture content in dried marijuana.

Financial Incentives for Higher THC Levels

The absence of federal guidance and state regulatory standards for cannabis testing contributes to the disparities. Accredited labs have financial incentives to attract and retain clients, potentially leading to biased results. This variation in testing outcomes is concerning, especially for medical marijuana patients who rely on consistent and accurate dosages. To improve the industry's credibility, more regulation and standardization are needed for cannabis testing.

Potential Manipulation of Samples

Current laws allow marijuana growers to select which samples to submit for testing, as long as they represent the entire batch and are no more than 15 pounds. This gives cultivators the opportunity to manipulate samples by treating them differently from the rest of the batch. For example, they might add ground marijuana powder (kief) to increase potency or use radiation or ozone to eliminate contaminants. Additionally, the location of the sample within the plant can affect the cannabinoid content, leading to natural variability.

Cultivators have a strong financial incentive to achieve high THC levels in their products, as many consumers prefer more potent marijuana. Some labs and cultivators are calling for increased state regulation to create a level playing field among companies. Without proper oversight and standardization, labs that adhere to scientific best practices may lose customers to labs that provide higher potency readings, leading to concerns about the integrity of testing results and consumer safety.

The Impact on Consumers

Consumers need to be cautious about relying solely on product labels when it comes to marijuana. Many cannabis activists and users have noticed that labels are not always accurate. Some have experienced stronger effects from low THC products than from higher ones, indicating that the potency listed on the label may not reflect the actual strength of the marijuana.

Due to conflicts of interest in the market, where growers can choose their own samples and seek the best lab results, trust in testing practices has been eroded. Some users, especially those who rely on cannabis medicinally, feel uncertain about the reliability of product labels. This uncertainty can be concerning because mislabeling could have health consequences, especially when certain compounds in marijuana interact with traditional medications.

As a result, consumers should be cautious and informed when purchasing marijuana products, especially for medical use, and consider other factors beyond the label when making decisions about potency and safety.

What the avid consumer think about marijuana labels

Many feel that there is a lack of serious regulation, and some less reputable growers are using the system for their own benefit, leading to inconsistencies in the products they sell. Some users believe that it may take several decades before meaningful reform can happen, and they hope for more open-minded and educated individuals to shape the industry's future. 

Although there are concerns about mislabeling and inconsistent products, some consumers advise doing thorough research and asking questions to make informed choices. They acknowledge the benefits of the legalization of weed but advocate for policy reform and greater transparency to address the industry's weaknesses and ensure a safer and more reliable system.


The investigation has shed light on the unreliability of marijuana product labels and the need for more stringent regulation and standardization within the cannabis industry. As consumers, it is essential to be aware of these discrepancies and advocate for greater transparency and accountability to ensure the safety and quality of the products we use.


Get Your Weekly Dose of Green

Subscribe for Exclusive Cannabis News, Weekly Deals, and the Industry's Latest Tech and Innovations!