Getting the Facts Straight: THCa vs. THC

As marijuana use in the US continues to be seen as less socially and legally taboo, both medical and recreational marijuana markets are being adjusted to further protect public health. Laboratory testing is increasingly becoming a requirement for marijuana or marijuana-infused product manufacturers, leading consumers into a retail environment where the potency of various plant compounds, known as cannabinoids, are represented in percentages. THCa and THC are the two cannabinoids most directly linked to the “high” users receive after smoking or otherwise heating raw or dried marijuana, but what is the difference?

Cannabis Research

THC Molecule Drawn Pen
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The macroeconomic inertia behind this emerging industry has forced state and federal government agencies and private research firms, among others, to invest firmly in research of the plant, resulting in solid evidence that cannabinoids (the various plant compounds producing the varied biological effects cannabis is known for) can have very different effects on

What It Means to Convert THCa to THC

Expressing the differences between the two cannabis plant compounds can be done by examining the two cannabinoids at the molecular level. THCa, shorthand for delta-9 tetrahydrocannabinolic acid, is the carboxylic acid form of THC, also known as delta-9 tetrahydrocannabinol. With regard to THCa, a carboxylic acid describes a molecular structure that includes a carbon and oxygen molecule.

Under normal circumstances, this prevents the psychoactive THC from being readily available. THCa, much like both CBDa and CBD, produces no psychoactive “high” or related euphoria. The process of removing the carbon and oxygen molecules, known as decarboxylation, is done simply by adding heat. It is why eating raw marijuana will not get you stoned, but smoking or otherwise heating it will.

It is also important to note that laboratory labels on medical or recreational cannabis usually list both THCa and THC concentrations. If the THCa is testing at 18% and the THC is testing at 1.5%, it may be easily assumed the product, once activated by heat, will be 19.5% THC. This is inaccurate. THCa percentages must be multiplied by the molecular mass of THC before being translated into final THC potential. In an equation, it looks like this:

THC total = (%THCa) x 0.877 + (%THC)

Interestingly, the analysis released by Kate Welch, pharmacist, suggests THCa can produce at least two clinically significant outcomes more effectively than THC can.

THCa vs. THC: Relieving Nausea and Vomiting

THCa and THC can both provide anti-nausea and anti-vomiting effects, yet research suggests THC is less potent in its antiemetic effect than THCa. In rats, the effect of THCa on nausea and vomiting is described as “considerable” and was shown to inhibit these effects by activating a neurochemical response in serotonin receptors (5HT1a, specifically) rather than an endocannabinoid system receptor, such as CB1 or CB2. THC produces its antiemetic effects by interacting with CB1 receptor sites.

THC vs. THCa: Managing Inflammation and Pain

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THCa and THC both have clinical potential as an anti-inflammatory and pain reliever, having even been shown to engage similar biological pathways to achieve this effect as ibuprofen or aspirin. Research has suggested that THCa and THC can block, to an extent, COX 1 and COX 2 enzymes from being released into the body. Among other things, COX 1 and COX 2 enzymes have been positively correlated with pain and inflammatory signaling. The ability of THCa and THC to interrupt COX 1 and COX 2 release can decrease inflammation and pain.

Research suggests that THCa, however, is more effective than THC at suppressing COX 1 or COX 2 enzyme release, indicating that not only is THCa non-psychoactive, it is better at managing inflammation and pain than THC.

THC vs. THCa: Neuroprotective

In animal studies, research on the cannabinoids THCa and THC, among others, has suggested the cannabinoid may have a neuroprotective effect. A neuroprotective effect occurs when cells, rather than degenerating, are encouraged to continue along healthfully. In so doing, this slows the rate at which an illness such as Parkinson’s disease can radicalize cells, which would otherwise lead to cellular degeneration, advancing the illness.

Individuals with neurodegenerative diseases such as Parkinson’s have been seeking beyond the realm of traditional western medicine for their condition, which has no cure at this point. While cannabis may offer several distinct benefits for such individuals, many of which may aid in existing therapies or treatments, for individuals with Parkinson’s, one of the main contributing factors of cellular degeneration is 1-methyl-4-phenyl pyridinium, known as MPP(+). THCa and THC may both exert an antioxidative effect on cells, helping sustain healthful functioning for longer, yet THCa was again singled out for being able to both increase the number of cells and sustain the healthy cell counts in regions where MPP(+) toxicity is present.


The long and short of it is, THCa and THC play different but complementary roles in the medical efficacy of the cannabis plant. More than anything else, we need to facilitate more federal funding for research into the miracles that marijuana can work, but that only starts when weed is removed as a schedule 1 narcotic and a healthy conversation can be opened up.