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Do You Know The Difference Between THC and THCa?

Posted: November 6, 2019 in Difference Between THC and THCa, Understanding Product Labels

With the constant stream of news and information about medical cannabis hitting the airwaves and social media, millions of Americans are familiar with THC, the most prevalent cannabinoid in cannabis. But, are you familiar with THCa, which is its acid form found in the raw and live cannabis plant? If you are not, this article is for you. I will attempt to explain the differences between the two cannabinoids, especially when it comes to making sense of their percentage values on medical cannabis labels.

While THC binds with both CB1 and CB2 receptors, THCa does not closely bind with either receptor. It is thought to interact with 5-hydroxytryptamine (5-HT) which is responsible for the output of serotonin in the body. The presence of THCa may also increase 2-AG, the naturally occurring endocannabinoid, which regulates many of our body functions.

When heat and/or sunlight are applied to the non-psychotropic THCa, it goes through the decarboxylation process which converts it into its psychotropic form, THC:

  • Sunlight Exposure; it is a slow process, but if a cannabis plant sits in the sun for an extended period, the THCa will convert to THC.
  • Room Temperature Exposure; if you leave a cannabis plant for 10 days in a 77°F environment, the THCa will convert to THC.
  • Heat Exposure by way of desktop and portable vape products, smoking devices such as pipes, joints, water pipes and bongs, dabs and concentrates, and oven decarboxylation for about 30 minutes at 240°F

Potential Benefits of THC and THCa

Both THC and THCa have many of the same potential properties. These include:

  • Anti-inflammatory
  • Neuroprotective
  • Sleep aid
  • Analgesic
  • Appetite stimulant
  • Anti-spasmodic
  • Antioxidant
  • Anti-emetic
  • Anti-proliferative

Additional Potential Benefits of THC

  • Anxiolytic
  • Vasodilation
  • Metabolic Output Increase
  • Addiction Treatment Option

Raw Cannabis

Think of raw cannabis as a vegetable which not only contains cannabinoids, but it also provides the body with fiber, calcium, and iron.

One popular method of consuming it is juicing it. It is a healthy way to start your day without any psychotropic effects. Researchers believe that in its raw state, it is assisting with the following:

  • Immune system booster
  • Strengthens bones
  • Improves neural functioning
  • Provides anti-inflammatory benefits

If you find raw cannabis too bitter, mix it with some more palatable flavorings like carrot juice or orange juice.

Lab Testing Methods

If you have been confused by the percentage values of THCa and THC on medical cannabis products, you are not alone. It is not possible to know definitively how much THCa converts to THC in any given strain. To compensate for this, labs use the following mathematical formula:

There are 2 common lab testing methods used to test the potency of cannabinoids in the cannabis plant.

1. Gas chromatography (GC) uses high temperatures to extract the cannabinoids by converting them into a gaseous mixture. The different cannabinoid levels are measured after running them through a filtering system.

The use of heat causes the following limitations:

  • Only the THC level is available at the exclusion of the THCa level
  • Some of the THCa decarboxylates
  • The actual THC potency level may be underestimated
  • The conversion of THCa to THC is only 70%
  • This process is fairly useless to calculate edibles because it is crucial to have the levels for orally active THCa and active THC
  • Separate levels for both THC and THCa
  • Testing of THC and THCa

2. Liquid chromatography (LC) is gaining more and more popularity as a better testing method. It occurs at room temperature, so no heat is applied in the process.

As a result, no decarboxylation occurs which allows for the following:

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

To illustrate this, we will use the following numbers:

THCa 20.89% and THC 0.25%

THCtotal = 20.89 % x 0.877 + 0.25% = 18.57%

THCa Research Studies

A 2011 study published in the Biological and Pharmaceutical Bulletin investigated the anti-inflammatory effects of THCa along with other cannabinoids.

A July 2013 study conducted by researchers at the University of Guelph in Ontario, concluded that THCa and CBDa had stronger antiemetic properties, appetite stimulation and reduced nausea, than THC and CBD, using rat models.

A December 2017 study, that appeared in the British Journal of Pharmacology, investigated the potential for THCa to treat neurodegenerative disorders such as Huntington’s Disease. The results suggested that THCa showed potent neuroprotective activity and is worth considering as a treatment option for neuroinflammatory diseases.

These few studies suggest that THCa may have even more powerful properties than does THC for certain conditions. Further research is definitely warranted.

Sources:, What is Raw Cannabis?, THCa and THC: What’s the Difference?, THCa vs THC: How to Read a Lab Result, Sirius J, July 20, 2015, Cannabinoids 101: THCa – The Apothecarium, Tetrahydrocannabinol: What is THC? Dr. Joseph Rosado, updated Dec 28, 2018


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