CBD Side Effects

CBD is known to have potential for treating many health conditions. The cannabinoid is non-psychoactive (does not cause a “high” feeling) and is largely non-toxic -But does it have any side effects?  

A 2017 review published within the journal Cannabis and Cannabinoid Research documents the safety and side effects of CBD. The review discusses the numerous clinical studies, most of them regarding epilepsy and psychotic disorders. The most common side effects of CBD appear to be tiredness, diarrhea, and changes in weight and appetite. The author of these studies also commented on the fact that these side effects seemed minor compare to other drugs used in treatment of the medical conditions mentioned above. 

Another review published in the journal Current Drug Safety, show that CBD has no adverse effects upon physiological parameters including heart rate, blood pressure, body temperature, psychological and psychomotor functions, gastrointestinal transit, and food intake.    

Liver Drug Metabolism

One side effect of CBD that is yet to be fully investigated is how it affects drug metabolism within the liver. CBD has been found to interact with drug-metabolizing enzymes such as the cytochrome P450 family. In essence, they deactivate each other. Since a large portion of pharmaceutical drugs on the market are metabolized by this enzyme, CBD can become a “competitive inhibitor” and therefore alter the effectiveness of the drug by slowing down or speeding up the rate at which it’s absorbed. The extent to which cannabinoid behaves as a competitive inhibitor depends on many factors such as how much CBD is administered, the unique attributes of the individual taking the medication, and whether isolate CBD or full spectrum is used. A 2013 report on a clinical trial using a pharmaceutical called Satives, a whole plant CBD spray, found no interactions with P450 enzymes when approx. 40mg were administered. A subsequent clinical trial however found 25mg of orally administered CBD significantly blocked the metabolism of an anti-epileptic drug. 


A team of Canadian scientists identified certain compounds in grapefruit that inhibit the expression of some cytochrome P450 enzymes, which is why physicians often warn patients not to eat grapefruit before taking their meds. CBD, it turns out, is a more potent inhibitor of cytochrome P450 enzymes than the grapefruit compound Bergapten. 

When taking pharmaceutical drugs, you should consult your physical before taking CBD. Such interactions may proven to be only a minor issue. CBD also poses beneficial actions on liver enzymes, such as enhancing levels of enzyme CYP1A1, which is capable of breaking down cancer causing substances like benzopyrene. 


Cannabinoids have been shown to be exceptionally non-toxic, which large doses such as 1500mg per day of CBD have been shown to have well-tolerated in human studies. This 10-20times more than the typical dose recommended. 

Love and light, 

Mimi May

  1. An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5569602/  
  2. Safety and side effects of cannabidiol, a Cannabis sativa constituent. – PubMed – NCBI  https://pubmed.ncbi.nlm.nih.gov/22129319/  
  3. Effects of cannabidiol in the treatment of patients with Parkinson’s disease: an exploratory double-blind trial. – PubMed – NCBI https://pubmed.ncbi.nlm.nih.gov/25237116/
This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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