What Is THC-O?

THCO Acetate
THC-O, or tetrahydrocannabinol-o-acetate, is a synthetic cannabinoid derived from hemp, created through a series of extractions involving CBD and delta-8 THC, and the addition of a highly flammable compound called acetic anhydride. It's gaining attention due to its potency, being approximately three times as potent as delta-9-THC and five times more potent than delta-8. However, its increased potency is not necessarily beneficial, as the endogenous cannabinoid system in the body requires subtle stimulation rather than a strong push. The legality of THC-O is currently ambiguous, with some arguing it's legal under the 2018 Farm Bill because it's derived from legal hemp plants, while others cite the 1986 Federal Analogue Act to claim it's analogous to a Schedule I drug.
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It’s not often that cannabis connoisseurs are stumped by marijuana trivia, but ask even the most enthusiastic activist about THC-O and you’re likely to be met with a blank stare. That’s because tetrahydrocannabinol-o-acetate is relatively new on the scene – but don’t worry: CannaMD has everything you need to know about this controversial cannabinoid covered.

Keep reading to learn more!

THC-O Definition: Is It A Stronger “Weed”?

THC-O (also known as THC-O acetate, THC acetate, and ATHC) is a synthetic – a.k.a. man-made – cannabinoid manufactured from hemp.

As Leafly explains:

To generate [THC-O], a highly-flammable compound called acetic anhydride is added to THC molecules. The process involves a series of extractions that begin with hemp, the low-THC cannabis plant that was made federally legal by Congress in the 2018 Farm Bill. First, CBD is extracted from raw hemp. Then delta-8 THC is extracted from the CBD. Finally, acetic anhydride is added to the delta-8 THC molecules to make THC-O acetate.

How Is THC-O Made?

Any description of THC-O is inevitably followed by the warning: Don’t try this at home! In an aptly titled interview – THC-O Acetate Q&A with Dr. Ethan Russo: ‘Don’t Go There’ – renowned cannabis researcher Dr. Ethan Russo stresses:

The process of making THC-O acetate is inherently dangerous. The acetic anhydride that’s part of the process is extremely flammable and potentially explosive. This is something that’s got to be done in a technical lab with a vacuum hood [and] no exposure to humans.

The Honest Marijuana Co. drives the point home:

ATHC [THC-O] can only be produced in a laboratory environment. You can’t pick up a few tools at your local hardware and whip a batch of ATHC in your kitchen. The results would be disastrous (that means flaming death, boys and girls).

But if THC-O is so dangerous to make, why is it gaining popularity?


THC-O is quickly capturing the public’s attention due to its comparative strength to THC. Industry experts claim:

[THC-O] is roughly 3 times as potent as delta-9-THC and 5 times more potent than delta-8.

According to Daily CBD:

THC-O is a prodrug, which means it doesn’t become active until after it’s metabolized by the liver.

Once it’s metabolized, what’s left is essentially just delta-9-THC. So why would this compound be any stronger?

There’s a lot of speculation around this, but the theory is that it comes down to bioavailability.

The acetylated version of THC is significantly more bioavailable than the non-acetylated version. Once THC-O is absorbed, the unique functional group (-O) is removed — allowing the THC to exert its effects as usual — only at a much higher dose.

However, Dr. Russo says that might not be a good thing:

[THC-O] reportedly is twice or maybe three times more potent than THC. Is that helpful? I’m going to say no, and the reason is that THC is what’s known as a weak partial agonist at the CB1 receptor. Now, let’s break that down: Weak is easy to understand. Partial means that its binding isn’t super tight. Agonist means it stimulates the CB1 receptor, which is the mechanism of action that produces the high of THC, as well as many of its therapeutic properties, including pain reduction, et cetera.

Potent sounds good. But this is a system in the body — the endogenous cannabinoid system — that works with a great deal of subtlety. In other words, what is needed when you’re using a drug to stimulate the system is a gentle nudge, not a violent push that comes from something that is a lot stronger than THC itself. So, potent is not necessarily better.

Is THC-O Legal?

Cannabis publisher Leafly has the perfect answer to questions surrounding the legality of THC-O:

It depends who you ask.

Some argue that THC-O is legal, under the 2018 Farm Bill, because the molecule is derived from legal hemp plants. However, opponents cite the 1986 Federal Analogue Act in claiming that any substance analogous to a Schedule I drug (like THC) would qualify, in turn, as a Schedule I drug.

As Leafly summarizes:

As with products containing delta-8 THC and delta-10 THC, products with THC-O exist in the marginal legal space between hemp (which is legal nationwide) and cannabis (which is not). State regulators and legislators are currently playing whack-a-mole with the growing number of hemp-derived compounds, banning novel compounds only to see new derivatives take their place.

Until THC-O and other hemp derivatives come under a state-regulated system, consumers will need to weigh the risks and benefits of these compounds for themselves.

Updated: March 21, 2024

Jessica Walters

Jessica Walters serves as CannaMD's Chief Medical Researcher. Prior to her time at CannaMD, Jessica earned her degree from Harvard where she focused on neuropsychology. Her personal research interests include psychosocial interventions for obesity, depression, and generalized anxiety disorders.


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