Confused by all the different products containing CBD? What CBD dosing you should take? Unsure of what to make of the labels? Don’t know what a milligram is?
This post is for you. We’ll discuss how CBD is quantitated, explain the units involved, and make sure you understand what you are buying.
Metric System
First, let’s do a metric system refresher. Weight (mass) is measured in the base unit of grams, while 1000 grams is equal to a kilogram, and 1000 milligrams is equal to a gram. There are 28 grams in an ounce, and 2.2 pounds in a kilogram. The abbreviations for kilogram and milligram are kg and mg. Volume, on the other hand is measured in the base unit of liters, and similarly, there are a thousand milliliters (ml) in a liter. Kiloliter is a rare unit to see: once volumes get that big, cubic meter become the base unit. One liter is a little more than an English quart.
Volume and mass are connected very nicely in the metric system: one milliliter of water weighs 1 gram, thus a liter of water weighs a kilogram.
CBD Dosing
CBD products generally come with two data points on the label: total CBD in mg, and the concentration of the contained CBD in the formulation. The total CBD is what you are paying for, while the concentration determines the dosing. Let’s consider total CBD for a moment. You may purchase a cream or an oil that contains 250 mg total CBD, while someone else might purchase a product with 500 or 750 mg total. How do you compare the price of the items? Well, you have to compare apples to apples, so you need to calculate the price per gram. This is simply the price paid divided by the mg times 1000:
By doing this simple calculation, you can directly compare the costs of various products, on a CBD basis.
Now, on to concentration. This is the mass of material in a given volume. Concentrations are measured in the units of milligrams per milliliter, or mg/ml. The concentration determines what volume of material is needed to achieve a desired dose.
Dosing Example
Say you have a product with a concentration of 35 mg/ml and you desire to measure out 20 mg of CBD. The required formula to determine the volume needed is simply the desired amount (the dose) divided by the concentration:
In the above example, the volume needed to obtain a dose of 20 mg would be:
Vol = 20 mg / (35 mg/ml) = 0.57 ml.
Another way to measure concentration is weight percent. This is just the weight of desired material (CBD) divided by the total weight of the product times 100:
If we assume our CBD is dissolved in a substance with a density of 1 g/ml, then the concentration of the above example is 35 mg/ml = 35 mg/g = 3.5 wt%.
Weight percent calculations are not normally done for solutions, since it is much easier to measure volume than weight (accurate weighing scales are expensive). However, the weight percent of THC in a CBD product must be below 0.3…so producers must be mindful of this.
CBD Dosing, Efficacy and Safety of Cannabidiol Administration in Adults
What is the appropriate dose? Well, that’s up to you. But now you should be able to accurately measure it.