Does the Light in Dispensaries Break Down THC?

If you walk into a modern dispensary, you’re probably going to see shelves lined with cannabis-packed mason jars. And unless there’s a power outage, these buds are probably illuminated by overhead lights. That makes sense—what store operates in the dark? The problem is that the product you’ve come to this store to purchase is adversely affected by prolonged exposure to light.

Light is necessary to grow cannabisThe irony is that light is also an important part of the growing process, especially when it comes to cultivating high-THC strains. The more UVB light a growing cannabis plant receives, the more potent its buds will be. On the flip side, once cannabis has been harvested, exposure to light will promptly deplete THC content because of the biosynthetic processes that occur at the molecular level in response to that exposure.

Early research into the preservation of THC published in a 1971 edition of the Journal of Pharmacy and Pharmacology determined that the best way to preserve the stability of THC was to store it at 0 degrees C, away from light, and under nitrogen. A 1976 study published in the same journal investigated the stability of cannabinoids stored in different conditions over the course of two years. Light exposure was implicated in the greatest losses of cannabinoids, and the most vulnerable products were cannabis oils. The second most consequential contributing factor to cannabinoid degradation was air oxidation. That study concluded that extracts were most protected if stored in the dark at room temperature.

Other Factors that Contribute to THC Degradation

More cannabis research is neededEven though cannabis has been legalized for medicinal use in over half of the country’s states, most doctors are reticent to incorporate it into their dissemination of care. Consequently, research into the plant is limited, and this is especially true when it comes to questions of each cannabinoid’s chemical stability. Much remains to be investigated, but this is what we know so far about the variables that affect the synthesis and deterioration of THC. 

Time and Temperature

Interestingly, the very elements that can degrade THC also catalyze the biosynthesis of THC to begin with. Raw cannabis does not contain any THC—it contains THCA, the acidic and inactive precursor to the psychoactive cannabinoid. Decarboxylation is the process by which a combination of heat and time cause the cannabinoids to lose a molecule of carbon dioxide.  That synthesis transforms each cannabinoid into something slightly different than it was before. THCA, a therapeutic but non-cerebral molecular structure, becomes THC, the psychoactive compound for which pot is most well-known.    

Temperature is another degradation factorA 2004 study published in the Journal of Analytical Toxicology investigated the stability of THC in varying temperatures over time. The study analyzed THC detected in authentic urine samples as well as THC-spiked urine samples. The study found that when stored in temperatures at 4 degrees C and above, the THC was unstable. More THC was detected in the samples between 2 and 15 days, suggesting that the temperature and time synthesized inactive THCA into THC while in storage. However, after 15 days of storage in 20 degree C temperatures, THC deteriorated. 

The exact temperature and duration of time by which decarboxylation occurred remained mysterious.  In 2016, a study published in Cannabis and Cannabinoid Research sought to fill in that gap by investigating the most effective decarboxylation methods for the synthesis of acidic cannabinoids into their activated forms. The study found that decarboxylation was complete (all of the THCA was converted to THC) after THCA was heated at either 110 degrees C for 30 minutes; at 130 degrees C for 9 minutes; or at 145 degrees C for 6 minutes. The study also found that after decarboxylation, the overall content of THC also decreased, indicating that as soon as THCA has been converted to THCA, it begins to deteriorate.   

Oxidation

The process of oxidation occurs when a chemical reaction causes the loss of electrons in a molecule, atom, or ion. Oxygen is not the only agent that can cause oxidation, but when it comes to THC degradation, that’s what we’re talking about. In practical terms, air flow is a contributing factor in the degradation of THC. When THC is oxidized, it converts to cannabinol (CBN), a useful, but non-psychoactive and much less potent cannabinoid.     

CBN makes you sleepA high content of CBN in a cannabis strain indicates a lot of THC degradation, so don’t expect to get a very potent high from it. However, CBN is still a sought-after cannabinoid for cannabis consumers who are looking for ways to enhance their wellness. CBN is a powerful sleep aid.  In fact, CBN is the primary reason why cannabis can be such an effective treatment for insomnia. It has also demonstrated potential as an antibacterial, analgesic, anti-inflammatory, appetite stimulant, anti-convulsive, bone stimulant, and glaucoma treatment. So if your cannabis is stale, hold off on throwing it out—it might still be useful if not particularly recreational.

It’s important to note that CBN is not a byproduct of temperature or light, but of oxidation. So if CBN is your desired product, it is still important to store cannabis in a dark, cool place.

How to Properly Store Cannabis

More research is needed on the stability of the cannabinoids that make the cannabis plant such a fascinating medical and recreational alternative, but it’s simple enough to extrapolate the basics from the existing literature. If you want to keep your cannabis flowers potent for as long as possible, there are four things you should avoid: heat, humidity, air, and light.

Cannabis is stored best when placed in an airtight, humidity-controlled, dark, cool location.  Packing cannabis in a tinted mason jar and placing that jar in a dark closet is the cheapest route to take. If you have money to spend, you can invest in a storage system like the Cannador. The Cannador is a discrete, modern storage container designed to control humidity. The box is opaque—it is a wooden case built out of solid mahogany—so there is no risk of cannabinoid deterioration as a result of prolonged UV exposure.

Dianna Benjamin

About the author: Dianna Benjamin is a freelance writer, teacher, wife, and mom horrified and fascinated by social justice and our inability--yet constant pursuit--to get it right.