Do Cannabinoids and Terpenes Degrade Over Time?
What are Cannabinoids?
Phytocannabinoids are several distinct sets of molecules produced by cannabis plants and when consumed, are a notable driver of many effects cannabis products provide to consumers. Cannabinoids can also be produced by the human body (endocannabinoids), however this article will focus strictly on phytocannabinoids, the compounds produced by cannabis plants. Phytocannabinoids, which, from now on, will be called cannabinoids, affect the endocannabinoid system, a network of chemical signals and cellular receptors throughout our brains and bodies (Grinspoon, 2021).
In the United States, cannabinoid concentrations of 0.3% or more are illegal (Hemraj, 2022). There are around 150 known cannabinoids, the most acclaimed one being tetrahydrocannabinol (THC), the compound that gives cannabis its psychoactive effects (Hemraj, 2022). Another popular cannabinoid is cannabidiol (CBD), which lacks psychoactive effects but is celebrated for its ability to reduce brain inflammation, help promote the growth of new brain cells, and treat numerous autoimmune and mental disorders (Hemraj, 2022).
What are Terpenes?
Terpenes are found in all plants, but in cannabis, they primarily contribute to its distinct scent and aroma (Sommano et al., 2020). Terpenes do not affect the cannabinoid system, which is why they are mostly legal in the U.S. (Hemraj, 2022). There are over 400 known terpenes available within the cannabis plant, and they are thought to offer many therapeutic benefits (Sommano et al., 2020). With that in mind, many manufacturers have been creatively enhancing terpene profiles in cannabis products (Erikson, 2019). As Omar Sacirbey reports for MJBizDaily, many regular customers are becoming more educated about terpenes and other compounds, which increases the importance of terpene content in cannabis (2021).
How Does Degradation Work?
Essentially, cannabis storage can significantly impact both the cannabinoid and terpene content and its degradation over time. Several factors can intensify the process, including temperature, lighting, humidity, and oxygen exposure.
Cannabis is very sensitive to temperature. Cannabinoids THC and CBD first appear as THCA-A (THC-acid-A) and CBDA (cannabidiolic acid) and then become THC and CBD through heating (Eichler et al., 2012). That said, too much or too little heat could be detrimental to potency. One study relied on the bioadhesive profiles of hydroxypropylcellulose as a means of gaging delta-9 THC degradation over time (Repka et al., 2006). The study found that “THC degraded fairly rapidly at room temperature” and stabilized as the temperature reached 4 degrees Celsius (Repka et al., 2006).
Terpenes have their own boiling points, which in some cases, can be quite different from other compounds. Boiling points are the temperature at which a compound begins to turn from a liquid to a gas, and when it comes to cannabis consumption, it can be a factor in the overall experience. For example, d-limonene, which is said to have anti-depressant and anti-mutagenic effects and a citrusy scent, has a boiling point of 177 degrees Celsius (McPartland & Russo, 2001). On the other hand, linalool, which has been said to have sedative and anxiolytic properties, has a boiling point of 198 degrees Celsius (McPartland & Russo, 2001).
Terpenes and cannabis are very sensitive to high exposure to UV light. Leafly reports that too much UV light may “break down organic matter” rapidly, causing degradation (Bennett, 2020).
Likewise, high humidity levels reintroduce moisture into cannabis flowers, which risks mold and ammoniated flavors (Bennett, 2020). Oppositely, low humidity can dry out leaves and create fragile, brittle flowers (Bennett, 2020).
Cannabinoids are similarly affected by humidity and oxygen. When given the wrong amount of heat, air, or light, THC can degrade into cannabinol (CBN) (Silva, 2022). CBN is not known to produce the same psychoactive effects as THC (Silva, 2022), so when THC degrades into CBN, the affected cannabis plant loses quality.
How quickly do cannabinoids and terpenes degrade over time?
Terpene degradation starts when the flower is cut from the stem (Moore, 2021). This is because terpene oils have lower temperature tolerances and evaporation rates and because as the plant dries out, its natural compounds cannot be replaced (Moore, 2021).
In a study focusing on how cannabis stored at room temperature lasts over time, S. Ross and M. Elsohly found that, on average, the sample’s THC concentration had a loss proportional to the time it spent in storage (1999). They reported that “a relationship between the concentration ratio of CBN to THC and the storage time… could serve as a guide in determining the approximate age of a given marijuana sample stored at room temperature” (Ross & Elsohly, 1999).
Another study found that after 127 days of storage, cannabis inflorescence lost between “18-34.3% of its total THC content for samples stored with and without external terpenes, respectively” (Bueno et al., 2022).
What are some proven methods to prevent degradation?
Since we know what causes degradation, it is a natural jump to figure out what prevents it. Proper temperature, humidity, oxygen levels, and light exposure controls are vital when drying, curing, storing, packaging, and transporting cannabis. It is important to prioritize the preservation of cannabinoids and terpenes throughout the lifecycle of your products. Leverage lab testing and internal studies to ensure your processes afford your products the best chance possible at arriving in consumers’ hands the way you intended it to.
While you cannot entirely prevent terpene and potency degradation, you can certainly slow it down. For accurate and reliable potency testing (cannabinoid and terpene), rely on Steep Hill labs to give you the information you need.
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