Cannabinoid Science 101: What Is Cannabidiol (CBD)?

A blue-gloved hand holding a small dropper bottle. In the background are cannabis plants

CBD is a non-psychoactive component of cannabis. CBD gained popularity much later than psychoactive THC, but was isolated more than 20 years earlier. Currently CBD is being thoroughly studied and investigated for its medicinal applications in treating numerous ailments. As it stands CBD now tops THC as the most well-understood cannabinoid in cannabis plants.

Cannabidiol (CBD) is one of the better-known and intensively studied phytocannabinoids. Acting as a mediator for the effects of THC, it is widely considered to be non-psychoactive in nature. However, research has indicated that CBD has a sedative effect. This may partly explain why cannabis strains high in CBD are known for their ‘stoned’ (relaxed and calm) effect rather than their ‘high’ (uplifted and energized).

If you follow the latest advances in dietary supplements for health and wellbeing you may already have heard of CBD products, even if you’ve never seen a cannabis plant. There is increasing and compelling evidence that adding CBD nutritional supplements to your diet can potentially alleviate and protect against a variety of conditions.

Chemical properties of the cannabidiol molecule

CBD has the same chemical formula and molar mass as THC (C21H30O2, 314.46 g/mol), although the molecular structure differs slightly. Like THC and most other lipids, CBD is hydrophobic and lipophilic, meaning that it does not dissolve or emulsify readily in water, but will dissolve in fat (as well as most organic solvents, such as butane and alcohol).

In acidic conditions, CBD cyclises (forms a new carbon ring) to become THC. In alkaline conditions (when water is present) CBD oxidises to become cannabidiol-hydroxyquinone, which is as yet poorly-studied, but may exert an inhibitory effect on the hepatic (liver) enzymes that are vital in the metabolism of ingested drugs.

The chemical structure of THC and CBD
The THC and CBD molecules, showing their extremely close resemblance

Cannabidiol in the endocannabinoid system

Although widely considered to have no affinity for the cannabinoid receptors, CBD has been shown in an at least one study to act as an inverse agonist of the CB2-receptor. An inverse agonist is a receptor ligand that induces an opposite response to an agonist. While THC increases the level of receptor activity above the intrinsic level found in the absence of any ligand, CBD reduces the level below this baseline. An antagonist, on the other hand, binds to a receptor and remains inactive, blocking the actions of nearby agonists.

The speculative new cannabinoid receptor, GPR55, may be influenced by the action of CBD. This receptor has been shown to respond to both CBD and THC, as well as the endocannabinoids 2-AG, anandamide, and noladin ether (also known as 2-AG ether). It has even been postulated as the CB3-receptor itself.

It is also thought that while CBD has little direct affinity for the cannabinoid receptors, it may have various indirect effects. For example, CBD inhibits the degradation of the endocannabinoid anandamide, by inhibiting the enzyme responsible for breaking it down. This increases anandamide’s endogenous levels and bioactivity. CBD may also act on receptors that are not part of the endocannabinoid system but work in combination with it.

A small dropper bottle, a glass jar full of blue pills, and coloured gummie bears

CBD’s effect on non-endocannabinoid receptors

CBD is a full, but weak agonist of the transient receptor potential vanilloid type 1 (TRPV1), which plays an important role in the response to heat and noxious stimuli. TRPV1 is a nociceptor: when sufficient excitation of the receptor occurs, signals are sent to the brain, triggering a set of automatic responses including the sensation of pain.

Various cannabinoids including the endocannabinoids anandamide and N-Arachidonoyl dopamine (a CB1-receptor agonist) affect the TRPV1 receptor. Conversely, several vanilloids affect cannabinoid receptors, including olvanil and pseudocapsaicin, but not including capsaicin itself. The close chemical similarity between many vanilloids and cannabinoids has led researchers to conclude that there is great therapeutic potential in researching vanilloid cannabimimetics (substances that mimic cannabinoids).

CBD has also been demonstrated to act as a 5-HT1a receptor agonist. This receptor regulates the expression of serotonin (5-HT) in the central nervous system, and may explain many of CBD’s anxiety- and depression-relieving properties. Further, CBD’s modulatory effects on the Mu and Delta opioid receptors, which are involved in the analgesic and euphoric response, may add to the overall effect experienced by the cannabis user.

A hemp field
The dominant cannabinoid found in industrial hemp is CBD

Cannabidiol and its potential for medicinal application

CBD has been described as being of even greater medical importance than THC. It is non-psychoactive, and can therefore be used safely without fear of intoxication. Beyond this, it has numerous known beneficial properties, and no doubt many that are yet to be discovered.

CBD has an analgesic, antidepressant and anxiolytic (anti-anxiety) effect, and is also being explored for its neuroprotective properties. Neuroprotection, in which the structures of the brain and central nervous system are protected against damage (including further damage, in the case of degenerative illnesses such as Parkinson’s), is a growing area of medicine which is of huge importance.

Perhaps most excitingly, CBD has been shown to have an inhibitory effect on the proliferation of cancer cells. It is thought that CBD’s effect on the CB2- and TRPV1 -receptors may play a role here, through the induction of oxidative stress. Systemic biological functions produce reactive oxygen species (ROS) such as peroxides, oxygen ions and free radicals, which must usually be detoxified to mitigate damage to the cells.

The most studied medicinal application of cannabidiol is in the treatment of epilepsy. The case of Charlotte Figi, whose parents successfully used medicinal cannabis to reduce the seizures she suffered due to Dravet Syndrome, led to the development of the Charlotte’s Web cannabis strain.

A cannabis bud

As more children were treated with this low THC, high CBD variety, scientists began investigating the remedial effects CBD could have on seizure incidence and seizure cessation. The ability of CBD to treat epilepsy has been investigated in multiple high quality, placebo controlled adjunctive-therapy trials. It is one of CBD’s only medicinal applications that has hard evidence as to its medicinal validity. Research into all the others continues apace.

  • Disclaimer:
    This article is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with your doctor or other licensed medical professional. Do not delay seeking medical advice or disregard medical advice due to something you have read on this website.


16 thoughts on “Cannabinoid Science 101: What Is Cannabidiol (CBD)?”

  1. Anna Maria Giovanelli

    In anziano in terapia con anticoagulanti può avere effetti collaterali negativi?

    1. Mark - Sensi Seeds

      Buon giorno Anna,

      Grazie per la tua domanda.
      Sfortunatamente, non sono in grado di fornire una risposta, poiché è al di fuori della nostra area di competenza.
      Poiché Sensi Seeds non è un professionista medico, non possiamo fornire alcun consiglio medico diverso dal consultare il tuo professionista sanitario registrato.
      A volte i nostri altri lettori saranno in grado di offrire le loro opinioni.

      Potrebbe interessarti anche il nostro articolo su Cos’è la cannabis medicinale e come scegliere una varietà di cannabis medicinale?

      Mi dispiace non poterti aiutare ulteriormente e spero che il blog continui a piacerti.
      Buona giornata,


  2. Thank you for the useful information, I have time now in my property in Berlin tranio/germany/berlin/ as I have now much time

  3. Alex Parker

    As much as know about CBD is that it’s a short form of cannabidiol, which is a chemical compound from the Cannabis sativa plant, which is also known as marijuana or help, according to the US National Library of Medicine.
    It’s a naturally occurring substance that’s used in products like oils and edibles to impart a feeling of relaxation and calm. Unlike its cousin, delta-9-tetrahydrocannabinol (THC), which is the major active ingredient in marijuana, CBD is not psychoactive. Marijuana has many curing effects on our bodies. It has proven to be a cure to certain health conditions. Many patients have relieved their chorionic pain using medical marijuana. Here I read some wonders of medical marijuana which are a must-read for marijuana users. There is a long debate on uses and misuses of Marijuana but if you manage your dose accordingly it is harmless. I really like this how beautifully you have explained everything. The best thing is you have mentioned the types and their effects on body, which are not known by a lot of people. The best thing is Marijuana/CBD is the non-psychoactive portion of the plant, so what that means is you won’t have any effects like euphoria. You won’t feel sedated or altered in any way.

  4. Hey there, This was very informative article with beautiful content, I would love to read more of this content in the coming days. Thanks for sharing.

    1. Suzanne Stephens

      I would love to get the word out that the thc/CBD tinctures that I have been taking for breast cancer have made my eating orders disappear.

  5. Hugh Horner

    Ave been taking tramadol 4 8 years now after lost 2 toes and part off my foot in work accident just want to no will these capsules help my pain and will i feel high on them

    1. Scarlet Palmer - Sensi Seeds

      Hi Hugh,

      Thank you for your comment. We are sorry to hear about your situation. As Sensi Seeds is not a medical agency or practitioner, we cannot give any kind of medical advice other than to consult your registered healthcare professional.

      We do have this article about CBD and how it could be used in medicine, which specifies that ‘THC causes the psychoactive effect of cannabis, whereas CBD is non-psychoactive. This means that it does not produce sensations of intoxication.’

      You may also find it helpful to contact a support group for medicinal cannabis patients. In the UK there is the United Patients Alliance, and throughout much of the rest of the world there is NORML, who should be able to put you in touch with a group in your area (search United Patients Alliance or NORML followed by your area name).

      With best wishes,


  6. Yes, cancer passes as a disease that is qualified to be treated with cannabis because it is reported with severe pain, and the sublingual tincture form of cannabis alleviates it. Patients with depression or other ailment make use of, say, vaporization form. The dose has to be monitored according to the most commonly reported symptoms like severe nausea and cachexia, as mentioned that CBD is indeed a non-psychoactive cannabinoid that may lessen the impacts of THC, and there can be implications as an anti-inflammatory and neuroprotective agent. I wonder about the cannabinoid ratio as well that it has to be balanced accordingly with THC: CBD showing efficacy. In cancer patients, this ratio is increased over time.

  7. Can I Put CBD Oil in my Coffee? - KyrosCBD

    […] So the overall answer is yes, you are able to add CBD oil to your morning java. This comes with a catch though, CBD is hydrophobic and lipophylic, this means that it resembles an oil chemically. […]

  8. Sarah Wilfley

    Excellent information and I agree. Facts and valid education is the ONLY way to help those who have no idea of what CBD is, the fear that the DEA have said claiming it’s illegal. We really do need more than what is out there. Great article!

  9. Awesome article! I just wish sources were cited, I’d like to look further into the studies you referenced.

  10. Nice article, and factually correct despite the lack of cited scientific references. It seems backwards that Canada would restrict public access to medical CBD, especially when it’s legally available OTC in the US? Makes one wonder what those politicians are smoking!

    1. This is definitely an amazing read so so glad I did the research and factual information is an eye opener for sure. I hope a lot of people read this I’m going to share it . Thank you

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    The Sensi Seeds Editorial team has been built throughout our more than 30 years of existence. Our writers and editors include botanists, medical and legal experts as well as renown activists the world over including Lester Grinspoon, Micha Knodt, Robert Connell Clarke, Maurice Veldman, Sebastian Maríncolo, James Burton and Seshata.
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