THCA is a non-psychoactive chemical found in raw cannabis.
Contrary to popular belief, THC is not the most plentiful chemical in marijuana. In fact, marijuana flowers hardly contain any THC at all.
Instead, THC is mostly present in the cannabis plant as a different compound called tetrahydrocannabinolic acid (THCA).
Have you ever tried to eat raw cannabis? If you have, you’ll know that cannabis in its raw form can’t get you high. That’s because THCA is non-psychoactive and must be converted to THC to have any noticeable effect.
THCA becomes THC when you add heat, such as by smoking or vaporizing your cannabis, through a chemical process called decarboxylation.
Cannabinoids and Cannabinoid Acids
Cannabinoids are the chemicals in marijuana that are responsible for its effects.
The production of cannabinoids occurs in tiny, crystal-like structures called trichomes. These trichomes are heavily concentrated on the flowers or “buds” of female cannabis plants.
Patients and physicians today know a lot about certain cannabinoids like THC and CBD. But THC and CBD are just two of over 113 cannabinoids that have been identified in marijuana.
What many people don’t know is that when the cannabis plant produces cannabinoids, it synthesizes them in their acid forms.
THCA is the most common cannabinoid found in fresh marijuana flowers. THCA is the acid form of THC.
Besides THCA, other compounds found in fresh cannabis include cannabidiolic acid (CBDA), cannabinolic acid (CBNA), cannabigerolic acid (CBGA), cannabichromenic acid (CBCA) and cannabinodiolic acid (CBNDA).
The decarboxylation reaction removes the carboxyl group from these acids, which transforms them into their active state. Through decarboxylation, THCA becomes THC, CBDA becomes CBD, and so on.
THCA vs THC
THCA is very similar in chemical structure to its non-acid counterpart THC.
But THCA contains a carboxylic acid group that is absent in THC. While this may seem like a small difference, it actually has a large impact on how THCA and THC affect the body.
THCA is also produced by biological processes in the plant, while THC is produced from natural conditions that the plant is exposed to (i.e. sunlight and heat).
In fact, THCA is the predominant cannabinoid in marijuana during its growing stages. THC, on the other hand, is mostly produced after the plant is harvested during the drying and curing stages.
Given these differences, it is important to consider how these compounds are similar.
In particular, THC would not exist if it weren’t for THCA. THCA acts as the backbone for THC production and is converted to THC when exposed to high temperatures, through a process known as decarboxylation.
Measuring THC / THCA Levels
The presence of THCA in raw cannabis creates an issue for testing labs when measuring the cannabinoid content of different strains. This is due to certain methods that rely on heat during testing, as well as differences in the molecular weights of THC and THCA.
Gas chromatography, or GC, is one testing method that changes the cannabinoid composition of samples. The machines used to perform this analytical test require heat and have been found to alter up to 70% of the THCA contained in samples, creating significant discrepancies among lab results.
Liquid chromatography, or LC, is an alternative to GC that does not use heat to determine molecular compositions of samples. This method of analyzing cannabinoid content is used more commonly in lab testing, since the results tend to be more accurate.
It is also important to consider the differences in molecular mass when converting THCA content to THC. For example, a strain with 15% THCA and 2% THC may be mistaken to have 17% THC when completely decarboxylated. The THCA content however needs to be adjusted according to the molecular weight of THC.
This is done simply by using the molecular weight of THC divided by the weight of the heavier THCA molecule to get a ratio of 0.877:1. This means that a single gram of THCA will only contain 877 mg of THC when fully decarboxylated.
In other words, a sample with 15% THCA and 2% THC would actually contain 15.155% total THC when entirely decarboxylated. This is because the THCA percentage needs to be multiplied by 0.877 and then added to the THC percentage to calculate the final THC content.
THCA and Decarboxylation
Like other acidic cannabinoids, THCA is produced through natural processes that occur in the cannabis plant. THCA can then be converted to THC by a chemical reaction known as decarboxylation.
Decarboxylation involves the removal of the carboxylic acid group found on THCA. This results in the production of THC.
The efficiency of decarboxylation depends on two factors: temperature and time. Decarboxylation starts to occur at 194°F (90°C) and speeds up as the temperature increases.
The optimal temperature for decarboxylation is between 284-320°F (140-160°C). At lower temperatures, decarboxylation can take hours while decarboxylation at optimal temperatures can occur in a few minutes.
Decarboxylation is usually achieved when cannabis is smoked, vaporized, or baked into edibles.
When fresh marijuana is baked into food, approximately 1/3 of total THCA will be converted to THC. This is because the internal temperature of the food will never reach as high as the temperature of the oven.
To fully decarboxylate THCA, it takes 3 hours at a temperature of 212°F (100°C) or 4 hours at 208°F (98°C).
Decarboxylation is a time-dependent process, meaning that more THCA is converted to THC when exposed to high temperatures for longer periods of time.
However, this only lasts for a short duration, after which THC can begin to breakdown into another cannabinoid known as CBN. This particular reaction is interesting, as THCA and THC degradation to CBNA and CBN can occur at lower temperatures than decarboxylation.
THCA does not undergo decarboxylation in the body when eaten, which explains the absence of psychoactive effects when consuming raw cannabis.
How To Consume THCA
THCA can be taken or consumed in a variety of ways, but because THCA becomes THC when heated, it generally cannot be smoked or vaporized.
The most common ways of taking THCA include topicals, tinctures and raw cannabis juice.
THCA-based topicals are available as lotions, salves, and oils that are applied to the surface of the skin. This allows patients suffering from pain or inflammation to apply THCA directly to an affected area and treat their symptoms without experiencing psychoactive effects.
When THCA is available in a pure crystalline form as either a powder or crystal, it can be measured into appropriate dosages that can be consumed in capsules or as a food additive.
Cannabis-based tinctures are also available. These tinctures are typically alcohol solutions containing THCA and sometimes other cannabinoid acids. They have the benefit of being consumed either under the tongue, on the skin, or swallowed.
Juicing raw cannabis is another popular way of ingesting THCA. This method of consumption does not interfere with the cannabinoid composition of the plant since it doesn’t involve heat, meaning THCA and other cannabinoid acids remain intact.
A juicing regimen recommended by Dr. William Courtney, a proponent for raw cannabis juicing, suggests a serving of 15 fresh leaves and 2 large fresh buds (2-4 inches wide) each day.
When juicing cannabis, the leaves and buds should be harvested prior to trichome clouding, which is indicative of decarboxylation.
Benefits and Effects of THCA
THCA is non-psychoactive and, as a result, has different effects than THC. THC works by binding to cannabinoid receptors, which are found in the brain and other parts of the body.
But how THCA affects the body is less clear. Studies suggest that THCA either does not act on cannabinoid receptors at all or has much weaker action on them than THC.
Nevertheless, THCA’s lack of psychoactive effects makes it more desirable than THC as a medicine. Unfortunately, not much research has been conducted on the medical uses of THCA.
In the few studies that exist, THCA was found to have the following benefits:
The anti-inflammatory properties of THCA make it unique from other cannabinoids. For example, researchers have examined the effects of THC and THCA on levels of a chemical that regulates immune cell function, known as tumor necrosis factor alpha (TNFα). They determined that THC increases the level of TNFα in the body, whereas THCA lowers its production.
This may contribute to the anti-inflammatory properties of THCA, as TNFα plays a role in inflammation and fever. It also suggests that THCA may be useful in treating pain, muscle spasms, menstrual cramping, and immune system disorders.
Marijuana is commonly used to treat nausea and vomiting, due to its anti-emetic (anti-nausea) properties. Interestingly, THCA has been found to have anti-emetic effects that are distinct from other cannabinoids like THC.
In one study, researchers found that THCA significantly reduced nausea and vomiting in animal models, although these effects were not achieved through activation of the CB1 receptor.
Much like other cannabinoids, THCA has shown potentially beneficial effects in cancer. THCA has been shown to slow tumor growth in a variety of tumor cell types. These effects however were not found to be as significant as other cannabinoids like CBD.
THCA may also have neuroprotective effects, meaning that it can help protect cells of the brain and nervous system (neurons) from damage. A study using brain cell cultures exposed to a toxic chemical known as MPP found that THCA protected the brain cells from toxicity.
THCA was able to increase the number of living cells after exposure to MPP by 123%. CBD was also tested in the study and showed similar levels of protection (117%). The neuroprotective properties of THCA suggest that it may be useful for treating neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease.
THCA is just one of the many cannabinoids in cannabis that display potential for improving health. And while it may be a precursor to THC, THCA seems to offer many benefits of its own.
Perhaps most importantly, THCA is a cannabinoid that does not produce a high, which is a critical factor for patients who require medical marijuana but do not enjoy the effects of THC.