Tetrahydrocannabinol (mostly commonly referred to as THC) is one of the over 100 total cannabinoids identified in cannabis — and it’s arguably the most significant too. THC is the principal psychoactive constituent of cannabis, it’s what gives you the high. But the medical benefits of cannabis may be linked to different cannabinoids.

THCA, also called Tetrahydrocannabinolic acid, may be one of those cannabinoids. THCA is not scheduled by the United Nations‘ Convention on Psychotropic Substances and it doesn’t have a psychoactive effect. But what exactly is it?

Before THC

THCA is essentially a precursor of THC. In living cannabis plants, THCA is found in variable quantities, but as the plants dry out, they undergo a chemical process called decarboxylation and morph into the psychoactive THC. So while their name and chemical structures are very similar, there are big differences between the two substances. THC gets you high, TCHA doesn’t.

Remarkably, although cannabis (Cannabis Sativa L.) has been domesticated and cultivated by human beings for over 4000 years as a source of food, fiber, and medicine, our scientific understanding of these cannabinoids is still in its infancy. In large part, this is owed to “war on drugs,” in which cannabis was essentially a taboo in medical research, despite showing some early promise for some applications. But with laws relaxing around the world, substances like THCA may be getting their moment in the spotlight. However, while CBD consumption has exploded (even though many of the claims associated with it are currently unsubstantiated), it’s a bit harder for THCA.

The problem with THCA is that it can be progressively decarboxylated to THC with drying or heating. Basically, when cannabis is smoked or cooked into edibles, THCA can morph into THC. In fact, THCA is often the majority constituent in substances like hashish or hash oil.

When THCA is sold for medical purposes, it is sold in the form of a white powder; this powder can be vaporized or smoked — and then you turn the THCA into THC and get the psychoactive effect. But what if you don’t want the high?

THCA can also be sold in capsules that are taken as a sort of supplements. However, there are currently no established medical applications for these capsules.

What THCA is good for

As is often the case with cannabis-derived products, there’s a lot of hype, but not all of this hype is backed by scientific evidence. Still, studies suggest some potential benefits for the substance (although more research is needed to say definitely what it can help with).

For instance, in 2013, a study found that THCA can help tackle motion sickness. That study was widely reported as it was understandably an encouraging result, but reports often failed to mention that the study was carried out on rats.

“THCA may be a more desirable therapeutic treatment for nausea and vomiting than THC because it is both more potent and devoid of psychoactive properties,” the study authors wrote at the time.

Similar studies found potential applications linked to analgesic or anti-inflammatory properties, but yet again, most studies were small-scale or not carried out on humans. Additionally, studies linked the usage of THCA to the preservation of neuroactivity but these should not be considered definitive.

Can you buy THCA?

The legality of substances such as THCA is volatile and may change on short notice. Because this article may not be updated as regularly, please review your local laws and don’t rely on this for legal advice.

Currently, THCA is not scheduled at the federal level in the US and the vast majority of other countries. However, this doesn’t always mean it’s legal — THCA can be considered an analog of THC and can be potentially prosecuted under the Federal Analogue Act. In practice, because THCA spontaneously decarboxylates into THC, no real-life sample of pure THCA can be completely free of THC. Notably, one THCA study found that “THCA decarboxylates even when stored between 4 and 18ºC (39-64ºF) so THC contamination in THCA is nearly unavoidable.” So there’s simply no THCA sample that doesn’t have at least a bit of THC.

In practice, hemp, which is legal, is defined as any part of the cannabis sativa plant with no more than 0.3% of tetrahydrocannabinol (THC). Marijuana, which is illegal in most states, contains more than 0.3%. However, some states, like Oregon, utilize a “total THC” criterion for post-harvest hemp, so they may have restrictions on THCA as well. So you can technically have a hemp bud with a THCA content of 20% and a THC content of <0.3% and that should be legal in some states, but not in others. Lastly, if you buy a high-THCA product and use it to get high, it can be legally argued that it is an analog to THC.

But if you to use the product for medical purposes, capsules or a THCA hemp flower is probably the best way to go. Just keep in mind that the permissibility of THCA flowers and capsules depends on the rules and legislation in a particular state.

You should also consult with your doctor before taking any supplements or pharmacological products. No doubt, there is significant potential to products like THCA, but the efficacy of these products is often unproven and overhyped — always follow science-based advice.

If you want to consume THCA in the form of a hemp flower, you probably don’t want to eat a whole nug of cannabis; and you don’t want to cook it either, because it just turns into THC. The simplest way is to grind it and add it to things like smoothies or spreadables, alongside other healthy types of food.