Short answer
The United States has no federal label standard for medical cannabis. Cannabis sits in Schedule I of the Controlled Substances Act, so each state writes its own label rules. Labels in states with medical programs list THC and CBD in milligrams per serving and per package, the serving count, and the batch number. FDA-approved cannabis drugs use a different system: standard drug labels with fixed milligram strengths.
How to Read a CBD Label: Serving Size, THC, and Batch Code
Numbers found on a state medical label
- THC in milligrams per serving
- CBD in milligrams per serving
- Total THC and total CBD per package
- Servings per package
- Net weight or volume in grams or milliliters
- Batch or lot number
- Harvest or manufacture date and an expiration date
- License numbers for the cultivator and the processor
- Warning statements on impairment, pregnancy, and child access
Flower labels work on percentages. A label reading 20% THC on a 0.5 gram joint equals about 100 mg of THC. Concentrate labels list both percent and total milligrams in most states.
how to understand thc percentage on weed labels
Serving and package limits
Several states set the same baseline for edibles.
- Colorado: 10 mg THC per serving and 100 mg THC per package for medical edibles.
- California: 10 mg THC per serving and 100 mg THC per package.
- Some states allow higher package totals for concentrates and tinctures. The range runs from 100 mg to 1,000 mg per package.
A 2017 study in JAMA tested 84 CBD products sold online. Measured cannabinoid content differed from the label in many samples. Some had less CBD than stated. Some had more. Some contained THC that the label did not list.
FDA-approved cannabis medicines
Four cannabis-related drugs carry FDA approval and full prescribing labels.
- Epidiolex: CBD oral solution, 100 mg per mL.
- Dronabinol (Marinol): capsules of 2.5 mg, 5 mg, and 10 mg.
- Syndros: dronabinol oral solution, 5 mg per mL.
- Cesamet: nabilone capsules, 1 mg.
These labels list an approved dose range, interactions, and storage conditions. State-legal medical products do not.
Why label numbers can differ from lab results
Potency testing uses high performance liquid chromatography (HPLC). The test measures THC and CBD in a sample from one batch. Variation comes from plant genetics, harvest timing, extraction, and mixing. Label rules also differ on whether the number covers THC acid (THCA) after conversion. A label that lists THC alone can read lower than a label that lists total THC after decarboxylation. Hemp rules add another layer. The 2018 Farm Bill defines hemp as cannabis with delta-9 THC at or below 0.3% on a dry weight basis, and hemp-derived products do not carry state medical labels.
How to read the label
- Find the serving size and the milligrams of THC per serving.
- Multiply milligrams per serving by the serving count to get the package total.
- Check whether the label reports THC, total THC, or THCA.
- Note the batch number and the test date.
- Compare the label to the certificate of analysis when the seller supplies one.
- Record the expiration date.
Open questions
No national database tracks label accuracy for state medical products. State rules on per-serving breakdowns for concentrates and tinctures vary, and several states do not publish testing tolerance limits. A patient who needs a precise dose has to rely on the state label, the lab report, and the batch number.