CBD stands for Cannabidiol, one of many cannabinoids from the hemp or cannabis plant. A cannabinoid is naturally occurring compound found in cannabis plants. Your body has many cannabinoid receptors that make up what’s called the endocannabinoid system, and this system plays a key role in keeping your brain – and therefore your body – robust and healthy.
How Does CBD Work?
CBD and THC interact with our bodies in a variety of ways. One of the main ways is by mimicking and augmenting the effects of the compounds in our bodies called “endogenous cannabinoids” – so named because of their similarity to compounds found in the cannabis plant. These “endocannabinoids” are part of what scientists refer to as the “endocannabinoid system.”
The discovery of the endocannabinoid system has significantly advanced our understanding of health and disease. It has major implications for nearly every area of medical science and helps to explain how and why CBD and THC are such versatile compounds – and why cannabis is such a widely consumed plant, despite its illegal status.
The endocannabinoid system plays a crucial role in regulating a broad range of physiological processes that affect our everyday experience – our mood, our energy level, our intestinal fortitude, immune activity, blood pressure, bone density, glucose metabolism, how we experience pain, stress, hunger, and more.
What happens if the endocannabinoid system doesn’t function properly? What are the consequences of a chronically deficient or overactive endocannabinoid system?
In a word, disease.
Cutting-edge science has shown that the endocannabinoid system is dysregulated in nearly all pathological conditions. Thus, it stands to reason that “modulating endocannabinoid system activity may have therapeutic potential in almost all diseases affecting humans,” as Pal Pacher and George Kunos, scientists with the U.S. National Institutes of Health (NIH), suggested in a 2014 publication.
By modulating the endocannabinoid system and enhancing endocannabinoid tone, CBD and THC can slow – or in some cases stop – disease progression.
For those who can’t obtain pharmaceutical CBD, there are numerous internet storefronts, community markets, coffee shops, health clubs, chiropractic offices, upscale boutiques and gas stations that retail various hemp-derived CBD oil products, including pure CBD isolates comparable in chemical make-up to Epidiolex.
CBD oil products and flower with varying levels of THC and CBD are also available for smoking or vaping at cannabis dispensaries in states that have legalized the herb for therapeutic use.
In response to massive consumer demand, a huge, unregulated market in CBD oil products reached a critical mass in 2018. A surge of consumer interest in all things CBD was suddenly newsworthy with hosanas of praise coming from athletes, film stars, soccer moms, and parents of desperately ill children.
CBD oil has been touted as a curative for the sick and a preventive for the healthy, an all-purpose palliative for pets as well as people of all ages.
But along with a growing awareness of cannabidiol as a potential health aide, there has also been a proliferation of misconceptions about CBD and cannabis therapeutics.
How to use CBD
Everybody processes cannabis and cannabinoids a little differently. The diversity of human experience means that finding your ideal form of cannabis consumption may take some experimentation.
The key differences between ways of using cannabis pertain to these questions:
- Onset: How quickly will cannabinoids begin to work?
- Dose: What’s a reasonable starting dose?
- Distribution: Which parts of the body will be most affected?
- Duration: How long will the effects last?
The dosage required, of course, depends on the quality of the product and the reason for its use. The doses we describe below are based on initially managing the psychoactivity of THC.
Edibles & Capsules
- Onset: 1-2 hours.
- Dose: The threshold for mild psychoactive effects is 3 mg THC in most new users. Doses of CBD-rich products range from 5 mg to hundreds of milligrams. 
- Distribution: Absorbed through the gut and modified in the liver, then spreads fairly evenly throughout the body.
- Duration: Psychoactive effects subside after about 6 hours in most people. Other effects may last up to 12 hours.
Ingested cannabinoids are absorbed through the intestines and sent to the liver. It takes about an hour to feel effects when taken on an empty stomach, or up to three hours with food. People should not re-dose THC edibles for at least three hours after ingestion.
On the way to the liver, cannabinoids will interact with receptors in the gut, so the effect on conditions like inflammatory bowel disease will be more pronounced. Once in the liver, three enzymes will start to modify THC and CBD in a process called “first-pass metabolism.” THC is largely converted to 11-OH–THC, which appears to cause a stronger high than THC. This, along with the long duration of edibles, is why new users should become comfortable with being high before using edibles containing more than 5 mg of THC.
The longer-lasting effect of edibles and capsules make them suitable for many chronic conditions.
Tinctures & Sublingual
- Onset: 15 minutes to an hour.
- Dose: 2.5-5 mg of THC and CBD is a common starting dose. This could cause a slight high in new users. 
- Distribution: Absorbed into the bloodstream in the mouth, then distributes evenly.
- Duration: After 6-8 hours, most of the THC and CBD has been metabolized or eliminated from the body.
Oral-mucosal drugs are absorbed directly into the blood vessels in the mouth and under the tongue. If sprayed under the tongue, the patient should try to wait at least one minute before swallowing (see Accidental Ingestion below.) Effects usually start after 15-30 minutes and peak around an hour and a half after administration. For consistency, it is best to avoid eating immediately before or after using a tincture. 
Oral mucosal tinctures usually come in one of two forms: an under-the-tongue spray or a dropper with a marking at a specific volume (usually 0.5 ml or 1.0 ml). This allows for consistent, measurable dosing. Pay close attention to the labels on these products. Products should be labeled with the dose of cannabinoids per spray or per ml.
Tinctures involve a solvent like ethanol or sesame oil.  Some of the adverse side effects attributed to cannabis extracts may actually be due to ingesting large amounts of the carrier oil.
Although sublingual sprays can provide rapid and precise dosing, they are often confusing for patients. If you spray CBD oil under the tongue but then swallow immediately, your body will process most of it like an edible. This means that you will receive a lower dose over a longer period of time. With CBD products, this may just make for a weaker effect. But with a THC-rich tincture, people may take another dose after half an hour – thinking they hadn’t had enough – leading to accidental intoxication with THC.
Other Routes of Cannabis Administration
Topicals and rubs are one of the more common kinds of cannabis products. They can be used effectively for skin or joint issues, but will not be absorbed into the bloodstream. The presence of terpenes or non-intoxicating acid cannabinoids (THCA and CBDA) seem to increase skin permeation, but still not enough to get it into the blood. Large concentrations of terpenes in topical products may irritate and damage the skin.
Although transdermal products are applied to the skin, their effects are nothing like topicals. A transdermal patch is designed to release cannabinoids into the bloodstream at a constant rate. If it has THC, the user can experience psychoactive effects.
Transdermal administration should confer an experience somewhat like sublingual use, although a transdermal patch could be designed to work for longer periods of time. It’s worth noting, however, that a transdermal CBD isolate failed to treat epilepsy in a clinical trial, whereas a sublingual CBD isolate was successful. Any company claiming to market a transdermal product should have public data demonstrating how well it is absorbed.
Cannabinoids are sticky, waxy chemicals. They like to mix with oil, not water. There are, however, a number of ways to get cannabinoids to dissolve in water , allowing for products like CBD-infused and THC-infused beverages. But the research in this area is limited. The processes that make cannabinoids soluble in water may also make it easier for your body to absorb THC and CBD. This means that such products will have a quicker onset compared to an edible (as quick as 20 minutes) and the dose may be stronger over a shorter period of time.
The process of solubilzing CBD and/or THC can reverse over time, so groups developing water-soluble formulations need to ensure the stability of their product. On the whole, ingesting water-soluble cannabinoids shouldn’t be much different than ingesting an edible, though the former may turn out to be faster acting and a bit more potent.
(Portions reprinted with permission from Project CBD / Adrian Devitt-Lee)