Cannabis 101: What’s the Difference Between THC and THCA?

what's the difference between THC and THCA?
Image by chuck herrera from Pixabay

Cannabis 101: What’s the Difference Between THC and THCA?

Cannabis labeling can sure get confusing. Unfortunately, there’s no consistency in what appears on your favorite cannabis strains and products. Some list THC, others list THCA, and those are just two of the cannabinoids that appear on retail products today. If you’re wondering what’s the difference between THC and THCA, you’re not alone.

States with legalized cannabis require products and cannabis strains to be lab tested to ensure that products are free of contaminants and harmful chemicals. They also run panels for potency and cannabinoids. Unfortunately, lab results aren’t standardized which can lead to confusion in cannabis labeling.

THCA Needs Heat to Become THC

Tetrahydrocannabinolic acid (THCA) occurs naturally in the cannabis plant and is the precursor to THC, the psychoactive compound that makes people feel euphoria and other sensations associated with feeling “high.” It only converts to THC when heated.

So, what does it mean when you see a product that says 24% THCA and 2% THC? It means that the laboratory used a testing method called liquid chromatography which separates the compounds in cannabis for analysis at room temperature instead of using heat.

Call Your Favorite Math Genius

What it means for you, the consumer, is that you’ll need to do some math to find out the true THC content of a particular product.

Here’s the formula, go nuts! THC total = (%THCA) x 0.877 + (%THC)

Or you can just sort of average it out – take approximately 15% off the THCA figure and then add the THC percentage. In the above fictional strain, 15% of 24 is around 3.5 then add the 2% THC for a sum of 22.5% THC in total for the strain. Annoying, isn’t it?

You’re most likely to see THCA listed on edibles but it can appear on any result from labs using this analysis method. If you’re not seeing THCA, then the lab most likely used gas chromatography which isn’t able to separate the two compounds from each other. If you only see a THC percentage, that should be the true total for that strain.

Want to know more about cannabinoids? Read: What are cannabinoids and terpenes?

Or check out this list of cannabinoids and their known effects.