Forms of Cannabis Intake

Forms of intake are the specific vehicles by which cannabis or cannabinoid-rich oils are delivered into the body. Both the plant material and the oils yielded at the conclusion of the extraction process influence the performance of the different forms of intake, which each have a particular set of benefits. Thus, the medicinal effect experienced by the end-user is a function of the quality of the raw material – the cannabinoid and terpene profile of the cannabis – and of the derived oil yielded during extraction. The goal is to preserve the fidelity of the volatile medicinal compounds – such as the cannabinoids, terpenes, and flavonoids – throughout the entire chain of custody so that the therapeutic effect is intact and the dose is delivered in the most efficacious means possible.

Cannabis (drug-containing plant) —>
extracted/infused oil (drug substance) —>
delivery/intake (drug product)

Forms of intake are designed according to specific pathways that allow the drug to enter into one’s system. These pathways are commonly referred to as routes of administration. The diagram below breaks down what is called the pharmacokinetics of THC – pharmacokinetics is the science concerned with the movement of drugs within the body. We see below that the “form” in which THC is administered determines how it moves and works medicinally inside the body:


Each form of intake is, therefore, formulated to take advantage of those pathways as effectively as possible in delivering a therapeutic dose of cannabinoids (e.g. THC or CBD).

The medicinal effects are then, we can conclude, dependent on the route of administration and the quality of materials by which the form of intake was made and the quality and effectiveness of the “form.” Below is a simplified breakdown of the important factors when considering each form of intake:

  • bioavailability – the fraction of the administered dose that reaches systemic circulation; the higher the number, the larger fraction of the dose that reaches systemic circulation. (Note: 100% bioavailability is intravenous delivery and the standard by which bioavailability is defined and compared).
  • accuracy of dose – the degree to which one can quantify the amount of medicine in each dose
  • time to onset – the amount of time before the medicinal or pharmacological effects are felt
  • duration of effect – the length of time the medicinal or pharmacological express themselves
  • quality and consistency of effect – the degree to which one can depend on a repeatable experience
  • Like the administration of your typical medicine, every patient’s care plan is unique and should reflect their respective wants and needs so long as the therapeutic dose is reached and the dose is properly titrated. In most cases, the intended goal is to do the least harm to the patient while maximizing the medical efficacy of each dose.

These are three common routes of administration of medical cannabis:

1. Route of Administration: Lungs/Inhalation
Form of Intake: Smoking and Vaporizing


1.1. Smoking

Smoking is the inhalation of combusted, dried flowers of the cannabis plant. It is one of the quickest ways to feel the effects of medical marijuana and the most common form of intake. Typically, the onset is rapid, immediate, and the duration is short. this “peak effect” is due to the high bioavailability of cannabinoids in the smoke and rapid metabolizing of the cannabinoids in vivo.

Pipes, joints, and water pipes are all used to smoke medical cannabis; however, habitually smoking medical marijuana can lead to lung damage as well as a habituation of “high” caused by the rapid onset and diminishing dose-response, i.e. “peak effect,” which is why registered marijuana dispensaries will, when asked, either recommend vaporization or alternative methods of intake instead of smoking.

  • bioavailability: high
  • dose accuracy: low
  • time to onset: seconds
  • duration of effect: 1.5 hours +/- 1.5-2 hours
  • quality and consistency of effect: high degree of variability

1.2 Vaporizing

Vaporizing is a process whereby the dried cannabis flower or extract or concentrate is slowly subjected to heat at lower and more precise temperature allowing for the therapeutic ingredients in cannabis, cannabinoids such as THC, to phase-change into a gas or vapor and extract from the plant without burning the plant. This process produces vapor instead of smoke.

While reducing the harm of long-term cannabis use, vaporizing does not really change the absorption of cannabinoids into the body. The cannabinoids are taken in through the alveoli in the lungs like smoking. It is safer than inhaling smoke and allows the patient to better control the dose.

  • bioavailability: high
  • dose accuracy: fair (depending on quality of the vaporizers)
  • time to onset: seconds
  • duration of effect: 1.5 hours +/- 1.5-2 hours
  • quality and consistency of effect: “lighter” high than smoking; high degree of variability

2. Route of Administration: Oral
Form of Intake: Edibles and Capsules


2.1 Edibles and Capsules

Infusing cannabis into butter or cooking oil or any other edible fat or sugar alcohol produces edible cannabis in the form of food or capsules. Edible consumption is occasionally recommended for patients who experience severe chronic pain because it’s effects manifest in more of a “body high” than a “head high” and have been described as a deeper or heavier feeling.

Patients should take caution with edible cannabis because it can sometimes take up to twenty minutes to an hour to take effect and can last for four hours or more. This is caused by a chemical change and loss of the molecular structure of THC during digestion and metabolism, a process known as first-pass metabolism.

A significant portion of the administered dose is destroyed due to the high PH of the stomach acids, and a part of the surviving portion of its molecules change into Δ11-HydroxyTHC, which is a much more psychoactive metabolite of Δ9-THC that takes much longer to cross the blood-brain barrier. When eating an edible, this causes one to easily over consume and for one to have a more significant psychoactive effect. So, it is recommended that patients eat small portion of edible medical cannabis at a time – a form of dose monitoring known as “titration” – and wait an hour or so for it to take affect before deciding how to proceed.

  • bioavailability: extremely low
  • dose accuracy: low
  • time to onset: hours
  • duration of effect: 4-6 hours
  • quality and consistency of effect: psychoactive; high degree of variability

3. Route of Administration: Skin
Form of Intake: Transdermal


Transdermal delivery is a self-contained, discrete dosage form which, when applied to intact skin, deliver the drug(s) through the skin at a controlled rate into systemic circulation. It comes in the form of a patch or a gel that is applied directly to the skin.

The advantages of transdermal are many. The dose is pre-loaded and is hidden from view – no smell, no ritual, easy to use. The rate at which the dose is administered is consistent and reliable happening gradually over a set time course.

  • bioavailability: medium
  • dose accuracy: very high
  • time to onset: 1.25hrs +/- 0.5 hrs.
  • duration of effect: 6-8 hrs.
  • quality and consistency of effect: light, high-functioning “high”; high degree of consistency

References, including figures

Grotenhermen Franjo. 2003. Clinical Pharmacokinetics of Cannabinoids. Journal of Cannabis Therapeutics. 3(1): 4-51.

Grotenhermen Franjo. 2003. Clinical Pharmacokinetics of Pharmacodynamics of Cannabinoids. Clinical Pharmacokinetics. 42(4): 327-60.

Huestis Marilyn A. 2007. Human Cannabinoid Pharmacokinetics. Chemisty & Biodiversity. 4(8): 1770-1804.