Cannabidiol (CBD) is a compound derived from the cannabis plant, known for its potential therapeutic properties. Like many organic substances, CBD is not entirely stable and can undergo chemical changes over time. Understanding how CBD degrades is important for consumers and manufacturers to maintain product quality and effectiveness, as degradation can affect its potency and properties.
Factors Influencing CBD Degradation
Several environmental factors contribute to CBD’s breakdown. Light, particularly ultraviolet (UV) light, accelerates the degradation of cannabinoids through photodegradation.
Heat also plays a significant role in CBD degradation. Elevated temperatures accelerate chemical reactions, leading to the breakdown of CBD, especially during storage or in high-heat delivery systems like vaping. Exposure to oxygen, known as oxidation, can alter CBD’s chemical structure, potentially reducing its potency and forming unwanted by-products. Additionally, the presence of acids or bases (pH variations) can catalyze degradation reactions, with CBD being particularly susceptible to conversion into other cannabinoids under acidic conditions.
Primary Products of CBD Degradation
The primary degradation product of CBD under common environmental conditions, especially when exposed to heat and light, is Cannabinol (CBN). CBN is a mildly psychoactive cannabinoid often associated with sedative effects, and its formation indicates a loss of CBD’s original properties, diminishing or altering the product’s intended effects.
Under acidic conditions, CBD can also convert into delta-9-tetrahydrocannabinol (Δ9-THC) and delta-8-tetrahydrocannabinol (Δ8-THC). Δ9-THC is the main psychoactive compound in cannabis, meaning CBD products exposed to acidic environments could potentially contain measurable levels of THC. This conversion has implications for product legality and consumer experience, as Δ8-THC has similar, though less pronounced, physiological effects to Δ9-THC. Other less common degradation products include cannabielsoin (CBE) and cannabidiol hydroxyquinone (HU-331), which are products of CBD oxidation.
Preventing CBD Degradation
To slow down or prevent CBD degradation, consumers should store products properly. Storing CBD in cool, dark places minimizes exposure to heat and light, which are major degradation factors. For instance, CBD is stable for at least 12 months when kept at 5 °C.
Using airtight containers, such as amber glass bottles, can limit exposure to oxygen, thereby reducing oxidative degradation. Checking expiration dates on CBD products can help ensure their potency and quality before use.
How the Body Processes CBD
When CBD is ingested, the body processes it through metabolic reactions, distinct from external degradation. This process primarily occurs in the liver, where various enzymes break down CBD into metabolites. The cytochrome P450 (CYP450) enzyme system, particularly CYP2C9, CYP2C19, and CYP3A4, plays a significant role in this initial breakdown.
These enzymes hydroxylate CBD, forming primary metabolites such as 7-hydroxycannabidiol (7-OH-CBD) and 6-alpha-hydroxycannabidiol. These hydroxylated metabolites then undergo further transformations, including oxidation to carboxylic acids like 7-carboxy-CBD (7-COOH-CBD). These metabolites are often conjugated with glucuronic acid by UDP-glucuronosyltransferase (UGT) enzymes, primarily UGT1A9 and UGT2B7, for water-soluble elimination. The body eliminates most of these metabolites through feces, with a smaller amount excreted in urine.