The Story of THCB: What is it, Where Does it Come From, and What Can it Do For You?

You may have heard that there are over one hundred cannabinoids found in cannabis. Why, then, do we only ever talk about THC and CBD?

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You know them well: THC refers to delta-9-tetrahydrocannabinol, the only psychotropic compound that is naturally present in appreciable quantities in cannabis. CBD is the nickname for cannabidiol, the hero of cannabis therapy. (Sometimes the non-psychotropic compound CBN, cannabinol, gets a brief spotlight. But still, if you google CBN the first thing to come up is the Christian Broadcasting Network – so it’s safe to say cannabinol still lives in relative obscurity.)

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So, what’s the deal with all those other, minority cannabinoids? Are they psychotropic? Do they have healing powers? Are they even remotely interesting?

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We’ve begun to hear more about minor cannabinoids like delta-8-THC and HHC. Another more recent minor cannabinoid to – quite literally – make a name for itself is a close sister of THC, called THCB. THC B stands for tetrahydrocannabutol.

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In this article, we’ll talk about how and why this cannabinoid made it out of obscurity. What is THCB, and what makes it different from THC? Is it safe and is it legal? And why might you seek out this cannabinoid above your other options?

The ABC’s of Cannabinoids

Ok, so there’s THC. There’s THCA. Now you’re telling me there’s THCB? And there’s also THCBA! It’s like trying to keep track of the Game of Thrones characters. Here’s a quick cast of characters.

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THC –THC stands for tetrahydrocannabinol. It is sometimes called delta-9-THC to differentiate it from other isomers. The delta-9 refers to the placement of the double bond. Notice that THC has a 5-carbon tail there on the right – that’s about to be important.

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THCA – THCA stands from tetrahydrocannabinolic acid. It is simply the carboxylic acid form of THC. This is actually the form that is found naturally in cannabis. This compound won’t make you high. When you apply heat (as in smoking or vaping), you provide the energy needed to break off the carboxyl group, leaving THC – which does make you high.

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THCB – THCB stands for tetrahydrocannabutol. It is the exact same thing as THC – except in THCB, that 5-carbon side chain is only 4-carbons long. (Technically, if we were naming THC by the same convention, it should be called tetrahydrocannapentol.) The THCB cannabinoid has also been referred to as THC-C4 in some research papers, another way of indicating that it is the 4-carbon variation on THC.

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THCBA – This is just the carboxylated form of THCB, the form naturally found in cannabis. When you heat it, the carboxyl group comes off to yield THCB (which, spoiler alert: makes you high).

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What Makes THCB Different From THC?

Here’s a summary of how THC and THCB are different from each other. It’s a pretty short list.

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*THC first characterized in 1964

*THCB first characterized in 2019

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We’ve already talked about the first two items on the list. There are basic chemical differences having to do with structure and concentration of these compounds. But what does that mean for the biochemistry of THCB?

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Is THCB Psychotropic?

The psychotropic activity of THC has mostly to do with the way it interacts with the human endocannabinoid system. THC “parks” in a receptor called CB1, where it exerts a powerful effect on the brain and the body. To determine if THCB can behave similarly, scientists look at whether THCB parks in the same parking spot. It does. This isn’t particularly surprising – chemicals that have similar structure often behave similarly.

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But actually, there are a lot of molecules that can park in that spot – it doesn’t necessarily mean that they’re psychotropic. CB1 is not like a button that you press to get high. It’s actually much more complicated than that. Instead of being a kind of “on-off” switch, CB1 is what we call a G-protein coupled receptor, which means that when something binds to it, it triggers a kind of domino-effect.

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For example, our body’s naturally produced endocannabinoids can also park in the same spot, but they don’t make us high. Because they park in a different “pose,” they also have a much lower affinity.

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CBD also interacts with CB1. But it has what’s called an antagonistic effect. It doesn’t exactly park there…but it does make it harder for THC to park there. That’s why CBD is shown to mitigate the effects of THC.

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To fully understand what THCB can do in the human body, researchers have to look really closely at how it’s parking at CB1. Here’s what they saw:

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THCB parks in a different “pose” compared to THC. Instead of a parking spot, imagine a chair that the cannabinoids can sit in. THC sits in the chair, and puts its 5-carbon tail through a hole in the chair. THCB, which only has 4 carbons on its tail, lets the tail rest on the chair instead of putting it through the hole.

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In this position, THCB is able to make more contact with the chair. The more contact, the stronger the binding affinity. In fact, THCB has about three times more binding affinity compared to THC.

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Another way researchers tried to investigate the bioactivity of THCB was by looking at how mice responded to it. They were able to show that THCB has potential analgesic (pain-relieving effects) in mice, but more research is needed.

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How Did THCB Make it Out of Obscurity?

Why so much talk about parking spots and carbon chains and mice? Why can’t we talk about THCB in humans?

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It’s hard to over-emphasize how new THCB is. Check out the table again: THC, as the most abundant cannabinoid present in cannabis, was characterized in 1964. The first time THCB was ever isolated and unequivocally identified was 2019.

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As you can imagine, these days we have much more advanced analytical instruments compared to what was available in 1964. Nowadays, we have technology that allows us to know the “exact” mass of molecular ions, out to four decimal places. That means we have a much better shot at identifying new cannabinoids, even when they’re present in low quantities.

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To really make sure you have the right compound, you usually have to confirm using an analytical standard. To make things more difficult, it was not possible to buy an analytical standard for THCB – so the researchers had to make one themselves.

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As you can see, there are a lot of steps to go through before we have actual clinical data about how humans respond to THCB.

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Minority Cannabinoids in the Entourage Effect

One of the reasons these kinds of developments are so exciting is because it will allow us to better explain the entourage effect. When we talk about the entourage effect, we usually talk about terpenes and other inactive compounds found in cannabis. But now we know that there are minor cannabinoids that could also be contributing. Even though THCB is not naturally present in enough quantities to exert a measurable effect by itself, it could have a biological effect when combined with 50 other similar cannabinoids.

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Is THCB Legal and Safe?

THCB is legal under the 2018 Farm Bill, as long as it is derived from hemp. Remember, it is only naturally present in extremely low amounts, which makes it tricky to extract. Scientists look for varieties that are already known to be high in THCB.

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The researchers who first isolated THCB knew that it would be present in greater quantities in a medicinal variety called FM2, so that’s the variety they chose for their experiments.

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THCB is different from semi-synthetic cannabinoids like delta-8-THC and HHC. Delta-9 and HHC are in a legal gray zone, because they are derived from CBD instead of isolated from hemp. Because of the wording of the 2018 Farm Bill, it is unclear if they should be classified as hemp derivatives or as synthetic cannabinoids (which would be subject to stricter legislation).

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THCB can be synthesized, but not from any of the natural cannabinoids found in cannabis. Even though it’s so similar to THC, it’s not chemically feasible to replace the 5-carbon chain in THC with a 4-carbon chain.

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Because its activity is so similar to that of THC, it is assumed to have a similar safety profile.

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To THCB or Not to THCB, That is the Question.

THCB is what you might call part of the vocal minority. Now that researchers have isolated it from the crowd, they’ve given it a voice. We’ll eventually be able to figure out: what are its distinguishing features? Does it have special properties? We’ll be able to add it to a repertoire of well-classified cannabinoids, to eventually give us the ability to fine-tune the cannabinoid experience.

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In the meantime, the experiment is yours if you want to try. Does THCB affect you differently compared to THC? Try it here. As always, feel free to contact us for a free consultation.