Cannabis potency testing measures the concentration of cannabinoids such as THC and CBD in a product. The results appear on labels as percentages or milligrams per serving, helping you compare products and estimate effects before you buy.
What Cannabis Potency Testing Measures
Labs analyze a sample to quantify cannabinoids. The main ones are:
- THC (tetrahydrocannabinol): the main psychoactive compound.
- CBD (cannabidiol): a non-intoxicating cannabinoid.
- Minor cannabinoids like CBG, CBN, and CBC.
- Terpenes in some tests, which contribute to aroma and flavor.
Testing may also screen for pesticides, heavy metals, and mold, but potency specifically focuses on cannabinoid content.
How Potency Testing Works
A lab receives a representative sample from a batch. Technicians prepare the sample and run it through instruments such as high-performance liquid chromatography (HPLC). This method separates and measures each cannabinoid. The lab calculates total THC by accounting for THCA, the acidic form that becomes THC when heated. Results are reported to the producer and often printed on the product label or a lab report.
Reading Potency Labels in a Dispensary
Labels typically show total THC and total CBD. For flower, potency is often a percentage (for example, 20% THC). For edibles and concentrates, you may see milligrams per package and per serving. A 100 mg THC chocolate bar with 10 servings means about 10 mg per piece. Check the serving size because it affects how much you consume.
Why Potency Varies Between Products and Batches
Potency can differ due to:
- Genetics: strains have different cannabinoid profiles.
- Growing conditions: light, nutrients, and harvest time matter.
- Extraction and processing: methods can concentrate or degrade cannabinoids.
- Storage: heat, light, and air can reduce potency over time.
Even within the same strain, two batches may test at different percentages. That is normal.
What to Check Before You Buy
Ask for a lab report or check the label for:
- The testing lab name and date.
- Total THC and total CBD, not just THCA or CBDA.
- Batch number that matches the product.
- Harvest or manufacture date.
If a budtender cannot provide a lab report, consider another product. Potency testing is your best tool for making an informed choice.