I’ve had a lot of people ask me what the difference is between THC and THCA. In this article I will go over their differences, how to calculate total THC, and why you’ll need this information in the near future.

THC (tetrahydrocannabinol) is the chemical compound most cannabis connoisseurs are familiar with. THC is responsible for the euphoric high and many of the health benefits that cannabis provides. However, THCA (tetrahydrocannabinolic acid) is the beginning stage of THC. THCA is naturally found in cannabis and turns into THC when heated, which causes the loss of a carboxyl group (also known as decarboxylation). Decarboxylation is needed in order for our bodies to feel the euphoric effects that THC brings.


This is why we burn the plant matter of cannabis when consuming it. When we ingest THCA we don’t notice the intense euphoria we associate with cannabis. However, THCA can still provide health benefits without decarboxylation. Studies have shown that THCA can help with:

  • Nausea
  • Appetite Loss
  • Arthritis
  • Lupus
  • Neuro Degenerative Diseases
  • Certain forms of Cancer

While studies have shown that THC also assists with each of those ailments (and many more), it is important to point out that cannabis can assist with many ailments without getting people high.

As the cannabis industry grows, growers will need to adjust their practices to meet large-scale demands. A big part of meeting those demands will be diversification- not just growing numerous strains but also delving into new products like edibles, topicals, tinctures, etc. In order to sell all of these amazing products, growers must get their flower and products tested by a reputable third-party.

These tests tell growers and their subsequent customers exactly how much THC, THCA, CBD, CBDA, terpenes, etc., are in their products. There are currently two methods for this testing: Gas Chromatography (GC) and Liquid Chromatography (LC).

Tested with GC, customers can only see the THC Total (THCT) and the CBD Total (CBDT).

Gas Chromatography requires the heating of the cannabis sample, which decarboxylates THCA enough to make it irrelevant (0%). GC is still very popular for growers that only produce flower. However, GC cannot be used to test edibles, tinctures, or any products that are not heated enough when consumed to decarboxylate THCA. If GC were used to test products that are not heated when consumed, the test would show more THC than the product really contains and would provide an inaccurate test result for the product.

LC, however, does not decarboxylate THCA into THC. Therefore providing growers and consumers with more information. If the product was tested with LC, you will see a percentage for THC, THCA, CBD, and CBDA. When reading these labels, it’s important to understand that THC≠THCA when it comes to percentages. You cannot simply add THC and THCA to get THCT (THC Total).

When THCA is heated and decarboxylates, it loses about 12% of it’s mass and therefore 12% of it’s potency as THC. Using the label for Dirty Girl by Cascadia Gardens I will calculate the total THC (THCT).


THCT = (%THCA x 0.877) + (%THC)

THCT = (26.3 x 0.877) + (0.9)

= (23.06) + (0.9)

= 23.96 = THCT

So the next time you go to the dispensary and see THC 0.9%, don’t despair. Look at the THCA percentage and do some mental math (if possible).




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