Know Your Medicine: THCA

Recently, many patients have been asking me if they should be using THCA (tetrahydrocannabinolic acid), and if you have been paying attention, you may have seen products labeled “THCA” in your local collective. So what is THCA, what does it do, and who should use it?

What is THCA?

THCA is synthesized in the trichomes of the cannabis flower when its precursor, CBGA (cannabigerolic acid), is exposed to an enzyme called THCA synthase.  THCA is considered to be “thermally unstable,” meaning that it readily converts to THC (D9-tetrahydrocannabinol) when heated.  This conversion of THCA to THC is called decarboxylation.

THCA will also convert to THC when stored at room temperature. Research shows that 22% of THCA in an olive oil extract will convert to THC after 10 days at 77℉, and in an ethanol extraction under the same conditions, 67% of the THCA will convert to THC. After 25 months at room temperature in glass bottles with very little light exposure,  approximately 20% of the THCA converted to THC. At temperatures over 176℉, 70-95% of THCA rapidly decarboxylates.  The human body cannot convert THCA to THC.

What does THCA do?

THCA is less studied than THC or CBD because raw cannabis typically has not been used by most recreational users or medical patients.  THCA is not psychoactive in animals even at high doses, and psychoactivity in humans is not reported. Research shows that THCA has many medicinal properties.

In an animal study,  low doses of THCA prevented nausea. THCA also has potent anti-inflammatory properties, inhibiting both COX-1 and COX-2 enzymes which block the production of prostaglandins, compounds that promote inflammation. THCA also inhibits TNF (tumor necrosis factor), another proinflammatory compound. THCA was found to be an effective neuroprotective and antioxidant in a research model of Parkinson’s disease. THCA also has been shown to have anticancer properties.  In one animal model of seizures, THCA had anticonvulsant effects.

It is unknown exactly how THCA imparts its beneficial effects. A number of studies have shown conflicting results. Researchers report that THCA is difficult to isolate from THC — remember that it is an unstable molecule that converts to THC fairly easily — so it is unclear if the result from the study (for instance, the cessation of nausea) is from THCA or from THC.  All THCA preparations contain at least some trace amount of THC, as well as other cannabinoids and terpenoids, so it is difficult to know if THCA is the compound that is conveying the beneficial effects. It appears from recent research that THCA does not attach significantly to the cannabinoid receptor.

Some scientists report that the reason THCA is not psychoactive is that it does not cross the blood-brain barrier and therefore cannot attach to cannabinoid receptors in the brain, however, THCA appears to stop seizures for some patients which questions this hypothesis.  The conclusion then must be that it has other mechanisms of action. Hopefully, research will sort out these and other questions about the mechanism of action of THCA.

Who should use THCA?

I have treated a number of pediatric patients suffering from treatment-resistant epilepsy with THCA, either as single cannabinoid therapy or in combination with CBD and/or THC.  I also have treated a patient with Alzheimer’s disease who, on just THCA alone, showed remarkable improvement. Arthritis and other chronic pain patients have reported good results with the use of THCA, often in combination with other cannabinoids such as CBD, THC, and CBDA.  Interestingly, patients report that THCA is effective at low doses, certainly lower than those of CBD. This may be due to the more robust terpenoid profile of an unheated preparation as certain terpenoids are lost when the flower is heated. My patients using THCA have not reported any unwanted side effects.

Every patient must use trial and error to find the best results for their particular condition, but certainly, THCA has numerous medicinal effects that may benefit patients with seizures, nausea, inflammation, neurodegenerative disease, and cancer.  THCA preparations in oil are more stable than those in alcohol, and these products should be refrigerated to minimize conversion to THC. Anecdotally, low doses appear to be effective and combination with other cannabinoid preparations seem to give patients good results.  More research is needed but this cannabinoid is showing that it, like the other cannabinoids, is mother nature’s gift.


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One thought on “Know Your Medicine: THCA

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