How much CBD should you vape? Working it out

Why no chart can answer this

A dose is established by trials that give measured amounts and record what happens. For CBD that has been done in one setting — severe childhood epilepsy, with a prescription product, by body weight, under supervision. For sleep, aches, tension or anything else, no dose has been established, and none of it was established by inhalation.

Inhalation adds a second problem on top. Even where an oral dose can be stated exactly, an inhaled one cannot: the amount that arrives depends on the device, the power setting, how long the draw is, how deep it goes and how much of the aerosol is exhaled again.

Turning milligrams into puffs

The arithmetic is rough but it is better than nothing, and almost nobody does it.

How much actually arrives

Swallowed CBD goes through the gut and the liver first, and only a fraction reaches circulation. Inhaled CBD skips both. The reviewed pharmacokinetic literature reports a higher and faster delivery by inhalation, with wide variation between studies and between people.

So the two routes are not comparable milligram for milligram in either direction: fewer inhaled milligrams may deliver more to the blood, faster, and for less time.

What inhalation is better for

Finding out whether something happens at all. An effect that arrives within minutes can be attributed to the thing you just did, in a way that an effect arriving ninety minutes after a gummy cannot — by then you have also eaten, moved, and had an hour of your day.

That makes inhalation the better tool for answering "does this do anything for me", and the worse tool for answering "how much should I take every day". Those are different questions and it is worth knowing which one you are asking.

Why the device changes the answer

• Power setting. More power vaporises more liquid per second, which means more milligrams per puff and more thermal degradation of the carrier.
• Draw length. A two-second pull and a five-second pull are not the same dose.
• Coil condition. An old coil delivers less and tastes worse; a new one delivers more from the first puff.
• The cartridge itself. Airflow and wick design vary enough that the same liquid in two devices is two different experiments.

Which is why keeping the hardware constant matters more than counting precisely. The count only means something if everything around it stays still.

A method that produces an answer

More is not reliably stronger

The instinct to take more of something that did nothing is a poor fit for this compound. In the one trial that compared CBD doses side by side for anxiety, the middle dose lowered anxiety and the highest did not. That was one outcome in one setting, by mouth rather than by inhalation, and it is still the only direct dose comparison in the literature.

What the label problem does to it

Every number above assumes the cartridge holds what it says. A 2017 analysis in JAMA found around seven in ten CBD extracts bought online were inaccurately labelled, and forensic analysis of CBD e-liquids has reported undeclared compounds including a synthetic cannabinoid.

Which makes a published batch certificate matching the code on your cartridge the difference between measuring something and estimating it. Without one, the arithmetic at the top of this page is being done on a number somebody wrote on a box.

What a certificate should actually say

"Lab tested" on a box means nothing on its own. A certificate that is worth the paper names the laboratory, carries a date and a batch code that matches your bottle, and reports more than the cannabinoid content.

• Cannabinoids, including THC. The easy half, and the only half most brands show.
• Residual solvents, left over from extraction.
• Heavy metals, which can come from hardware as well as from the plant.
• Pesticides, on a crop that is grown agriculturally.
• What was looked for and not found, which is the section that would have caught the undeclared synthetic cannabinoids described above.

A brand that publishes all five per batch is doing something the shelf does not require of it, and on a product you inhale that is most of what separates one bottle from another.

Whether tolerance applies here

People who vape nicotine or cannabis are used to needing more over time, and reasonably ask whether CBD works the same way. The honest answer is that it has not been studied in the way that question deserves.

What is known points away from it. Tolerance to THC is a well-described adaptation at the CB1 receptor, the receptor CBD does not activate in that way. There is no equivalent body of evidence describing CBD tolerance, and the long-running epilepsy trials, where people took large doses daily for months, are the closest thing to a test of it.

When to stop rather than increase

The reported effects of CBD at high doses are sleepiness, loose stools and reduced appetite, and they are the sensible ceiling for an experiment. Anything sharper than that — a racing heart, disorientation, a head change that feels like intoxication — is a reason to stop and look hard at the product, because CBD is not intoxicating and something in the cartridge may not be CBD.