While each has its pros and cons, HPLC is the hemp and cannabis potency testing gold standard due to its speed and ability to measure the largest spectrum of cannabinoid analytes.

GC is less commonly used for testing potency in cannabis and hemp. You will most often see this method used in cases where a long list of cannabinoids isn't needed. The largest difference is that a GC will decarboxylate all acid-cannabinoids in its measurement process. The outcome is that you end up with a single result for the total of the acid and neutral cannabinoid (e.g. a single result for total THC instead of separate results for THC and THCa). One benefit of the GC is that you can also test for terpenes on a system configured for cannabinoid analysis!