The cannabinoid into which tetrahydrocannabinol (THC) breaks down after prolonged periods of time. The degradation can be accelerated by exposing dried plant matter to oxygen and heat. Cannabinol (CBN) is only mildly intoxicating; with current research indicating it may only be one-fourth (¼) the potency of THC.
“This CBN weed is over four years old and aged to perfection.”
“If you're having trouble sleeping, take advantage of the CBN in your poorly stored cannabis.”
More about CBN Cannabinol
In more ways than one, CBN is something of a “sleeper” cannabinoid. It's far less popular than THC or CBD, and at the moment, it's certainly less en vogue than terpenes. To those aware of its existence, however, CBN is also known as “the sleepy cannabinoid in old weed.”
Given its sedative effects and dominant presence in aged cannabis, CBN's reputation — both as a sleepy cannabinoid and one less desirable than THC or CBD — is warranted, although it lands just shy of the big picture. CBN's distinct sedative quality is undoubtedly the thing that sets it apart from other cannabinoids, but that doesn't mean we don't have much to learn from the CBN cannabinoid, or much to gain from becoming more familiar with its chemical makeup and effects.
Much of the research around cannabinol effects, notably sedation, has been done in rodents. A 1975 study showed CBN enhances the sedating effects of THC in rats and mice. Sedation is commonly associated with CBN, because aged flowers have much more CBN than fresh flowers. The sedation is not necessarily a product of CBN; rather, aged cannabis with CBN cannabinoids will be sedating because it has also lost lower molecular weight monoterpenoids in favor of more sedating sesquiterpenoids. The sedation factor is one of several primary differences when comparing CBN vs. CBD, as the latter cannabinoid does not cause sleepiness.
Is CBN Legal?
At this time, CBN is not on the list of scheduled controlled substances in the United States. However, the legal issue may prove to be more complex as CBN could be considered an analog of CBD or THC, which are both Schedule I substances under federal law. (Hemp-derived CBD is legal in the US.)
How CBN Works
One of the most valuable aspects of cannabis is the way its cannabinoids offer multiple mechanisms of action, or pathways through which they produce an effect. CBD and THC produce beneficial effects, in part, because they can activate multiple biological pathways at once. They may also produce a wider variety of effects through channels separate from the CB1 and CB2 receptors.
The CBN cannabinoid hasn't been researched nearly as rigorously as CBD, THC, or even some terpenes. But as researchers begin to mine cannabis for every possible benefit, the demand for more information will likely reveal the full profile of CBN's effects.
The Connection Between CBN and THC
Our current understanding of CBN as a major cannabinoid dates as far back as a 1999 study in which the United Nations Office on Drugs and Crime (UNODC) tested cannabis potency loss over time. According to the study, THC content in the tested cannabis sample dropped to half of its original potency after four years. Furthermore, as THC oxidized and dissipated, it began to convert to CBN. The study also found that the first two years of improper storage were when the most THC degradation occurred, drawing a clear connection between THC-CBN conversion and plant vulnerability.
In the simplest terms, this study shows that THC degrades into CBN over time, which means cannabis will typically become CBN-heavy the longer it ages. The study also reveals why CBN and THC cannabinoids share alternative mechanisms of action to CB1 and CB2 receptors. When a lab result shows high-CBN, it indicates the cannabis has aged significantly. As the UNODC study concluded, “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.”
CBN Benefits and Medical Uses
CBN may be a result of THC degradation, but it also presents new pathways to exploration of medical cannabis use. THC and CBD have both become highly valued for their therapeutic versatility in recent years. CBN, though far less well known than CBD or THC, also boasts an impressive list of potential medical uses.
CBN remains primarily valued as a potent sleep aid. According to an analysis from Steep Hill Labs, 5 mg of CBN is as effective as10-mg of diazepam, a prominent pharmaceutical sedative. As an anti-insomnia medicine, CBN is not only potent, but also easy to obtain, as long as you have access to cannabis. If you're finding it difficult to locate a CBN-heavy cannabis product (which, given their current rarity on the market, is more than likely) all you have to do is store some cannabis in a non-airtight container and let it sit for a few weeks or months.
In addition to its effectiveness as a sleep aid, CBN has recently been identified as a potential painkiller. As previously mentioned, CBN has different mechanisms of action than CBD and THC. It is considered a weak CB1 partial agonist, which means it binds directly to the receptor but induces much lower effects compared to a full agonist. In fact, CBN has been shown to only produce approximately 10% of the activity of THC. Rather than alleviate pain by way of CB1 or CB2 receptors, CBN releases peptides from sensory nerves, activating an alternative nerve mechanism to achieve the same ends.
CBN is one of several cannabinoids with the potential to fight bacteria. When tested on multiple antibiotic-resistant bacteria, CBN was highly effective, and may prove a viable option for reducing methicillin-resistant Staphyloccus aureus (MRSA) bacteria in the future.
Cannabinoids can also be effective anti-inflammatories. CBN, though not as widely used for anti-inflammatory purposes as CBD or THC, may have similar abilities to treat a variety of inflammatory ailments. A 2009 study on cannabinoids as novel anti-inflammatory drugs, for example, identified CBN as a possible treatment for inflammatory disorders such as allergic asthma. Research has also revealed that CBN can treat glaucoma by reducing inflammation that causes intraocular pressure.
Studies dating back to the 1970s identify CBN as an effective treatment against convulsive illnesses. Similar to CBD and THC, CBN has the potential to reduce seizures and epileptic symptoms. Patients should be warned, however, that CBN's anti-convulsive properties may be more effective in conjunction with CBD and THC than as an isolated compound.
Bone Cell Growth Stimulant
CBN ticks all the usual boxes of a medicinal cannabinoid — pain relief, anti-inflammation, appetite stimulation, etc. But it may also stimulate bone marrow cell growth. By gathering and modulating stem cells, CBN may be an effective cannabinoid in creating bone tissue and healing bone fractures.
In addition to the potential medical uses already covered, CBN may be an effective appetite stimulant. A 2012 study found that rats administered with CBN showed a sizable increase in both quantity and duration of feeding. These findings present the possibility of using CBN as a non-intoxicating alternative to THC appetite stimulants.
Pharmacological History of CBN
Veteran cannabis users may be surprised to learn that CBN was the first phytocannabinoid ever to be isolated — from a red oil cannabis extract by Thomas Barlow Wood, WT Newton Spivey, and Thomas Hill Easterfield in 1896. It wasn't until 1932 that R.S. Cahn further clarified CBN's chemical structure, paving the way for the cannabinoid's chemical synthesis and official discovery by two separate research groups — Lord Todd in the UK and R. Adams in the U.S. — in 1940.
After its 1940 discovery, the CBN cannabinoid was thought to be the primary psychoactive component of cannabis for more than two decades. Then, Israeli researchers Yechiel Gaoni and Raphael Mechoulam successfully isolated THC in 1964 and discovered its psychoactive dominance within the cannabis plant. This discovery led to further research that identified CBN as an oxidized, degraded version of THC, but without THC's intoxicating effects.
More research is needed to fully grasp CBN's sedative effects. Some even theorize that terpenoid profile changes may contribute to the sedative quality of aged cannabis as much as, if not more than, THC degradation.
When someone is using a product labeled “CBN,” it is not an isolated cannabinoid. It contains other cannabis compounds in addition to CBN, including some THC and terpenes, many of which are sedating.
The only way to know the specific medicinal properties of a cannabinoid is to study it as an isolated compound. A 1976 study did just that, by exploring the sedating effects of CBN alone and in combination with THC. Researchers found that CBN was an “inactive” cannabinoid alone — meaning it was not sedating when given to volunteers. Interestingly, CBN produced greater sedation when combined with THC, compared with THC alone. Thus, it is the combination of these different compounds that might be providing sedation, likely not the cannabinoid itself.
Where Can I Find CBN?
Cannabis patients looking for a non-intoxicating alternative to THC may be interested in CBN cannabis, but at this point, you probably aren't going to find a CBN-heavy cultivar at your local dispensary.
However, that doesn't mean a healthy dose of CBN is out of your grasp. Arguably the easiest way to get CBN is from the aged flower you might happen to have on hand. THC-heavy cultivars left lying around for a while will be particularly ripe with CBN. If you don't happen to have old flower on hand, buying new flower and leaving it somewhat exposed for a while will also do the trick.
What Is CBN Oil?
More and more, as each cannabinoid is explored for its full medicinal value, CBN may become a more common cannabinoid and show up in CBN oil, CBN tincture, CBN capsules, and topicals. In fact, a select few companies are already jumping on board the CBN train.
Most cannabis contains less than 1% CBN initially, but there are plenty of strains out there with more CBN-producing potential than others. Anyone looking to develop CBN from aged cannabis should look out for cultivars known to have higher CBN content, such as Strawberry Haze, Jorge's Diamonds, A-Dub, Amsterdam Flame, Death Star, Cataract Kush, Kosher Kush, Pineapple Chunk, Purple Sour Diesel, Red Dragon, and Shark Shock.
Some CBN enthusiasts have noted that the cannabinoid's sedating effects are stronger when it's taken with food. If you're interested in trying this method, making CBN capsules at home is fairly simple and usually cost-effective. Essentially, all you have to do is simmer some aged cannabis in coconut oil on low heat for a couple of hours, then place the infusion into a capsule maker.
And if you're able to cultivate your own cannabis medicine, you may want to consider ripening your home-grown weed for a high-CBN yield. Simply harvest about 7-10 days after your usual harvest, when the plant has over-ripened and converted its THC into CBN.