The psychoactive effectiveness of cannabis, or its potency, is not permanent. Like any natural product, cannabis begins to degrade immediately after harvest, causing a gradual reduction in the compounds responsible for its effects. This loss of potency is an inevitable chemical process driven by environmental factors. Understanding this degradation helps consumers make informed decisions about proper storage.
The Chemical Process of Cannabinoid Degradation
The reduction in psychoactive potency is fundamentally a chemical change known as cannabinoid degradation. This process centers on the breakdown of delta-9-tetrahydrocannabinol (THC), the primary compound that produces the characteristic effects. THC is not stable and naturally transforms into other compounds when exposed to certain conditions.
The main degradation pathway involves the conversion of THC into cannabinol (CBN). This transformation is primarily triggered by oxidation, which occurs when THC reacts with oxygen, often accelerated by light or heat. CBN is far less psychoactive than THC, meaning its formation directly reduces the product’s overall potency. The presence of CBN in a sample is often an indicator that the product is older or has been improperly stored.
Standard Potency Reduction Timeframes
The rate at which potency diminishes depends heavily on the product form and storage conditions. Dried cannabis flower, which retains its natural structure, is relatively stable and typically keeps for six months to one year before noticeable potency loss occurs. Under poor storage conditions, such as exposure to room temperature and air, the rate of THC oxidation can be as high as 5% loss per month.
Cannabis concentrates and oils generally experience a slower rate of degradation compared to flower because extraction and processing techniques often stabilize the cannabinoids. While concentrates are more resilient, improper storage can still lead to changes within about six months. For long-term storage, concentrates may retain about half of their original potency after two years.
For edibles and tinctures, the shelf life of the cannabis content is often determined by the other ingredients in the product. A hard candy or gummy, which provides a protective barrier, may keep the embedded THC potent for a long time. However, porous baked goods allow for more oxygen exposure, which accelerates degradation. Potency is generally considered significantly reduced after about six months, especially if the product is not kept in an airtight container in a cool, dark place.
Optimizing Storage to Preserve Potency
Preserving potency involves creating a controlled environment that mitigates the four primary environmental factors driving cannabinoid degradation: light, temperature, oxygen, and inappropriate humidity levels. Controlling these elements directly slows the chemical reactions that convert THC into less effective compounds.
Light Control
Ultraviolet (UV) light exposure is a significant catalyst for cannabinoid breakdown. Cannabis should always be stored in opaque containers, such as dark-colored glass or metal, and kept in a completely dark space, like a cupboard or drawer. This practice shields the product from the energy that accelerates degradation.
Temperature Regulation
Heat is a major factor, as elevated temperatures speed up the chemical reaction that transforms THC. The ideal temperature range for long-term storage is between 55 and 65 degrees Fahrenheit (13 to 18 degrees Celsius). Storing products above 70 degrees Fahrenheit (21 degrees Celsius) can rapidly accelerate potency loss, so locations should be far from heating vents, electronics, or direct sunlight.
Limiting Oxygen Exposure
Limiting exposure to oxygen is achieved by using truly airtight containers. Oxygen facilitates the oxidation reaction that turns THC into CBN, so minimizing the air volume around the product is beneficial. Glass jars with tight-sealing lids or vacuum-sealed bags are effective tools for reducing oxygen contact.
Managing Humidity
Humidity control is necessary to prevent both mold and desiccation, which affects texture and terpene content. The optimal relative humidity (RH) range for storing dried flower is between 58% and 62%. Humidity control packs placed inside the storage container are a practical solution for maintaining this specific range.