Quick answer
The mg on a medical cannabis label is the weight of the active cannabinoid, usually THC, CBD, or both, in that product. It is not the weight of the plant material. A 10 mg THC gummy holds 10 mg of THC. One mL of a 20 mg/mL tincture delivers 20 mg. Flower is the odd one out: it gets labeled by percentage, so you do the math yourself. One gram of flower that tests at 20% THC equals about 200 mg of THC in the jar, spread across however many puffs you take.
how to read cannabis dosage labels
Why label mg is not the same as mg in your body
Inhaled THC reaches the blood in minutes. Eaten THC passes through the liver first, where it converts to 11-hydroxy-THC, a metabolite that crosses into the brain more readily. That is why 10 mg in a cookie can hit harder and last longer than 10 mg from three puffs. Milligram counts are a starting point for comparison, not a promise about effect.
Common reference points
- 2.5 mg: a common starting dose for someone new to oral THC.
- 5 mg: a low to moderate single serving.
- 10 mg: the standard single serving in most U.S. markets, and the per-serving cap in many states.
- 100 mg: typical cap for a whole package of edibles where limits exist.
- CBD: often dosed far higher. Clinical cannabidiol products run 100 mg/mL, and 10 to 50 mg per day is routine in trials.
How to read the three most common labels
Edibles
Look for mg per piece and mg per package. A 100 mg chocolate bar scored into 10 squares is 10 mg per square. If it is not scored, you are guessing, and a knife cut is rarely even.
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Tinctures and oils
The label gives mg per mL. A 30 mL bottle of 20 mg/mL contains 600 mg total. A standard dropper is usually 1 mL, but check, because some hold 0.5 mL. Half a dropper of a 20 mg/mL oil is 10 mg.
Capsules and tablets
These are the easiest to trust because the dose is fixed. Scored tablets let you split down to 2.5 mg or 5 mg without measuring anything.
Flower math
Take the percentage, move the decimal, and multiply by the weight in milligrams. A 0.5 g joint of 18% flower carries about 90 mg of THC in the material. You will not absorb all of it. Combustion destroys some, and inhalation efficiency is often estimated around 20 to 50 percent, so a few puffs might deliver 5 to 15 mg. Treat that as a rough band, not a precise number.
Where convenience fits
Walk a dispensary shelf and the deciding factor is rarely potency. It is whether the dose is already measured. Pre-scored chews, single-serve 2.5 mg mints, metered-dose inhalers, and droppers with printed graduations all sell because they remove arithmetic from the equation. For a patient who needs a stable dose at 7 a.m. before work, that is a real benefit. The trade-off is that convenience hides dose creep. It is easy to take one more mint when the unit is small and the package reseals, and easy to lose count. A product that measures itself still needs a patient who writes it down.
A practical starting routine
- Pick one product and one route. Do not change both at once.
- Start at 2.5 mg THC or less if you are new, or at your current dose if you are not.
- Wait. Two hours for oral, 15 minutes for inhaled, before adding more.
- Hold that dose for three to five days before adjusting.
- Log time, dose, and effect. Patterns show up in a week that you cannot feel in a single session.
Milligrams are a measuring stick, nothing more. They tell you how much you took, not how much you will feel. Body weight, liver enzymes, tolerance, and whether you ate beforehand all shift the response. Use the number to stay consistent, then adjust based on what your own log says.