What’s In Your Weed?

From cannabinoids to contaminants, there are many compounds in cannabis to keep an eye on.

For decades, consumers have had to rely on rumors and hearsay when discussing and obtaining cannabis. While the days of purchasing cannabis in back alleys are gone in many states, the misinformation passed around anecdotally for years remains prevalent and consumers remain in the dark about what they should be looking for when selecting their product or medicine. 

Fortunately, new research is emerging that furthers our collective understanding of cannabis and how it works. Every day we learn more about cannabinoids, terpenes, flavonoids, and other naturally-occurring compounds that give cannabis its psychoactive and medicinal properties. 

We are also learning more about the potential risks that come with cannabis consumption. Contaminants like heavy metals and mold are prevalent in cannabis plants and can be harmful to humans – especially immunocompromised medical patients. 

Let’s take a look at some of the most important compounds to keep an eye on when purchasing cannabis.


You’ve probably heard of THC – short for tetrahydrocannabinol. This cannabinoid is the primary psychoactive element in cannabis, but there are hundreds of others that contribute to the effects of this plant as well. 

These are the compounds that are most commonly listed on product labels. In Massachusetts, dispensaries are required to list THC content along with any other “marketed” cannabinoids. Currently, THC content appears to be the largest factor in consumers’ minds when purchasing cannabis and consequently is the compound dispensaries and cultivators focus on.


These compounds, also known as “terps,” are responsible for the aromatics of cannabis and all other plants. Studies have shown terpenes may have unique medicinal properties that could alleviate symptoms from ailments like migraines, pain, or inflammation. There is also a theory – termed “The Entourage Effect”- that terpenes work synergistically with cannabinoids to deliver the effects cannabis is known for. 

Regardless of whether this theory is true, it’s clear terpenes play a larger role in cannabis than current mainstream thought. Humans have been experiencing and benefitting from terpenes throughout history, whether it be while on a stroll through the woods or peeling a lemon. To learn more about terpenes, click here


While cannabis has proven itself to be a natural therapeutic for a variety of ailments, it is still an organic being subject to contamination via its environment. In fact, cannabis is an excellent bioremediator, meaning it sucks elements from their growth mediums, like soil or water, at a high rate. 

This makes it extremely susceptible to heavy metals, like lead or cadmium. These metals can accumulate in the plant structures that are eventually consumed by humans. While they are not dangerous in small quantities, daily exposure to high concentrations can be harmful to human health. 

In addition to heavy metals, cannabis is also vulnerable to microbiological contaminants like yeast or mold, especially if grown outdoors. Mold contamination can be particularly dangerous for immunocompromised patients, which can result in inflamed sinuses and lungs. In rare cases, it can even cause fungal infections. 

Ensure the product you purchase has been tested by a reputable lab, and don’t be shy to ask the budtender for a Certificate of Analysis to prove it. 

Shelf Life

Cannabinoid degradation is a well-known issue throughout the cannabis industry. Over time, cannabinoids will naturally degrade due to environmental factors like temperature, air, and light. 

This means if a product was tested and reported to contain 18% THC on a certain date, three months later that number has likely dropped. This is important to take into consideration when purchasing a product, especially if you are looking for a specific dose. 

Make sure to check the label for dates on when the product was tested and packaged. You can always try out this handy cannabis stability calculator as well. While it will likely not be precise, it can give you a good indicator of how much variance there may be from the reported cannabinoid content. 

At the end of the day, it’s important to know what’s in your weed not only for health reasons, but to ensure you will experience the effects you’re looking for. Most dispensaries will provide a Certificate of Analysis on request, so don’t be shy about asking for one or asking questions about their storage practices. The more informed you are, the better your cannabis experience will be. 

To learn more on this topic, check out our upcoming event What’s In Your Weed: The Educated Consumer. Our Vice President of Scientific Operations Scott Churchill will be joined by Dr. Jordan Tishler of InhaleMD at District Hall in Boston on Thursday, April 14 to talk about cannabinoids, terpenes, contaminants, and much more. Click here to register

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