What Are The Differences Between THCa vs THC?

Jessica McKeil December 2, 2019 0 comments

Cannabinoids found in raw cannabis are receiving attention for their potential medicinal properties.

Beyond the most popular and prevalent cannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD), there are dozens of other compounds worth scientific exploration. Many experts believe these secondary compounds also have important medicinal value. Some of the lesser known cannabinoids are tetrahydrocannabinolic acid (THCa) and cannabidiolic acid (CBDa). And while all cannabinoids share structural similarities, there are important differences for THCa vs THC. The same goes for CBDa vs CBD. While these may be similar in form, they have key molecular differences that impacts medicinal value.

What do we Know About THCa vs THC?

THCa is the acidic precursor to THC. It is a cannabinoid existing almost exclusively within live and freshly harvested cannabis plants.

As a naturally occurring cannabinoid, THCa quickly degrades into THC after exposure to heat, UV light, or oxygen. This process either happens over time as the plant material dries or rapidly, during processing.

The official name for the purposeful process of transformation is called decarboxylation. Decarbing, as it’s commonly called, is the activation of THC through vaping, smoking, and baking (all types of heat). This degradation structurally changes the molecule, and THCa loses its carboxyl group (the acid) to transform into activated compounds.

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The longer cannabis stays in storage, the more THCa converts to THC. This means that even raw cannabis may cause intoxication if it has been sitting there long enough. Patients looking to access THCa in the highest levels will need live-resin products, fresh plant material, and properly cured fresh flower.

THCa vs THC represented by fresh cannabis

What is CBDa?

Very similar to THCa, CBDa is the parent cannabinoid to CBD. Strains advertised as CBD-rich were technically rich in CBDa first. Decarboxylation (heat, oxygen, and UV rays) transforms the acidic, fresh cannabinoid into its activated form: CBD.

Molecularly, the difference between CBDa vs CBD also comes down to the loss of its carboxyl group. The precursor cannabinoid is most prevalent in fresh plants, properly cured CBD-rich flower, and live-resins, just like THCa.

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Understanding Potency: What does THCa on Labeling Mean?

If labels were 100 percent accurate, all flower would indicate THCa ratios – not just THC. But, most labels only state THC content. This may be because consumers might not understand how to turn THCa and THC into a final potency. In addition, this conversion rate can be unpredictable.

However technical it may seem, it’s still inaccurate to leave THCa off the labeling. This is also the case with CBDa vs CBD on product labels. For simplicity’s sake, however, producers and dispensaries typically forgo the technicalities of THCa and CBDa.

Calculating the total THC from THCa is not straightforward. The formula (Total THCa x 0.877 + total THC) is not user-friendly.

What are the Benefits of THCa vs THC?

At the time of writing, there were few well-controlled studies on THCa vs THC (or CBDa vs CBD). In fact, researchers have only completed very preliminary work on either acidic cannabinoid. However, like their more famous cannabinoid cousins, both THCa and CBDa also influence the endocannabinoid system. These regulate symptoms related to inflammation, memory, mood, the sensation of pain, and gastrointestinal processes.

The following is a summary of the research on THCa:

  • In 2013, the British Journal of Pharmacology published, “Tetrahydrocannabinolic acid reduces nausea-induced conditioned gaping in rats and vomiting in Suncus murinus.” This in-vivo animal study demonstrated how “THCa potently reduced” nausea-related behavior and vomiting in rat and mouse models.[1]Rock, E. M., Kopstick, R. L., Limebeer, C. L., & Parker, L. A. (2013). Tetrahydrocannabinolic acid reduces nausea-induced conditioned gaping in rats and vomiting in Suncus murinus. British … Continue reading
  • Five years later (also in the British Journal of Pharmacology), came the study, “Tetrahydrocannabinolic acid is a potent PPARγ agonist with neuroprotective activity.” The scientists behind this paper investigated several cannabinoids for their neuroprotective capacity within a Petri dish.[2]Nadal, X., Del Río, C., Casano, S., Palomares, B., Ferreiro-Vera, C., Navarrete, C., Sánchez-Carnerero, C., Cantarero, I., Bellido, M. L., Meyer, S., Morello, G., Appendino, G., & Muñoz, E. … Continue reading

Scientific Application

The promising cannabinoids, including THCa, were then further applied to mouse-models. Their results indicated THCa had “potent neuroprotective activity. This is worth considering for the treatment of Huntington’s disease and possibly other neurodegenerative and neuroinflammatory diseases.”

  • In 2017 came the study, “Anti-Inflammatory Activity in Colon Models Is Derived from Δ9-Tetrahydrocannabinolic Acid That Interacts with Additional Compounds in Cannabis Extracts,” published in the pages of the Journal of Cannabis Cannabinoid Research.[3]Nallathambi, R., Mazuz, M., Ion, A., Selvaraj, G., Weininger, S., Fridlender, M., Nasser, A., Sagee, O., Kumari, P., Nemichenizer, D., Mendelovitz, M., Firstein, N., Hanin, O., Konikoff, F., … Continue reading

THCa vs THC represented by fresh cannabis

The team behind the in-vitro study looked at cannabis extracts on epithelial cells and on colon tissues to determine the potential for the treatment of inflammatory bowel diseases, like Crohn’s and ulcerative colitis. Their early work discovered cannabis extracts containing THCa were most effective, at least in the laboratory.

What About CBDa vs CBD?

What about the benefits of CBDa? To date, there is even less known about the possible medical applications of CBDa. The early work is as follows:

  • In 2014, the authors of “Cannabidiolic Acid, a Major Cannabinoid in Fiber-Type Cannabis, is an Inhibitor of MDA-MB-231 Breast Cancer Cell Migration,” published their findings on the anti-tumor characteristics of CBDa. They discovered “for the first time” that CBDa effectively reduced the migration of aggressive breast cancer cell lines.[4]Bolognini, D., Rock, E. M., Cluny, N. L., Cascio, M. G., Limebeer, C. L., Duncan, M., Stott, C. G., Javid, F. A., Parker, L. A., & Pertwee, R. G. (2013). Cannabidiolic acid prevents vomiting in … Continue reading
  • In the British Journal of Pharmacology, the article “Cannabidiolic Acid Prevents Vomiting in Suncus Murinus and Nausea-Induced Behaviour in Rats by Enhancing 5-HT1A Receptor Activation,” detailed how CBDa reduced symptoms of nausea in mouse models of the condition.[5]Rock, E. M., Kopstick, R. L., Limebeer, C. L., & Parker, L. A. (2013). Tetrahydrocannabinolic acid reduces nausea-induced conditioned gaping in rats and vomiting in Suncus murinus. British … Continue reading
  • As the latest addition to the body of work, in 2019, researchers laid out early details about how CBDa may reduce seizures in a paper “Pharmacokinetics of Phytocannabinoid Acids and Anticonvulsant Effect of Cannabidiolic Acid in a Mouse Model of Dravet Syndrome.”[6]Anderson, L. L., Low, I. K., Banister, S. D., Mcgregor, I. S., & Arnold, J. C. (2019). Pharmacokinetics of Phytocannabinoid Acids and Anticonvulsant Effect of Cannabidiolic Acid in a Mouse Model … Continue reading

THCa vs THC represented by person trimming fresh cannabis

How to Get the Most Medicinal Value Out of THCa and CBDa

Both CBDa and THCa are sensitive to heat, oxygen, and UV rays. As such, they are more challenging to capture for medicinal applications. The traditional methods of smoking, vaping, and baking are too harsh to protect the volatile nature of these acidic cannabinoids.

Patients must strictly control the heat exposure during consumption to reap the medicinal value without destroying these sensitive cannabinoids. One of the easiest ways is to vaporize fresh flower within a user-controlled dry-herb vaporizer (Ex: The Volcano, Pax). Investigate lab results before consumption and pre-set the temperature as follows:

  • THC: 311 to 315 °F / 155 to 157 °C
  • THCa: 220 °F / 105 °C
  • CBD: 320 to 356 °F / 160 to 180 °C
  • CBDa: 248 °F/ 120+ °C

A Bright Future for Minor Cannabinoids

THCa and CBDa represent just the tip of the proverbial cannabinoid iceberg. With hundreds of compounds, including terpenes and flavonoids, the cannabis plant has so much left to unravel.

In the future, experts will have a better understanding when comparing the medical benefits of THC vs THCa. It is still early days in the world of cannabinoid research.


Author avatar

Jessica McKeil

Jessica McKeil is a freelance writer focused on the medical marijuana industry, from production methods to medicinal applications. She is lucky enough to live in beautiful British Columbia, Canada where the cannabis industry is exploding. When not writing, she spends much of her time exploring in the coastal forests.

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