CBD and Human Health: What's the Evidence?

CBD and Human Health: What's the Evidence?

We get asked a lot: is there actual scientific evidence supporting CBD's role in human health? 

The answer is yes, but the research is really just getting started.

A shortage of good studies––with blinding, controls, and an adequate size for producing statistically-relevant results––has for years made establishing unequivocal proof of CBD's activity in various health issues difficult. The pharmaceutical industry, which understands how to create such trials and can afford to do so, has largely ignored cannabis as a research subject, as the cannabis plant is not patentable and includes THC, a Schedule I substance.

Furthermore, natural cannabis products are derived from a wide assortment of cannabis plants, each containing very different quantities of THC and CBD as well as trace amounts of minor cannabinoids such as CBG and CBN. Each of these compounds has differing effects on the body’s cannabinoid receptors, depending on the concentration achieved in the blood. This variability in the cannabinoid mixture complicates comparisons among and consolidation of the results of different studies.

Fortunately, as consumer interest in CBD grows, so does the Food and Drug Administration's need for high-quality data to inform its regulatory pathway for the industry.  This has incentivized funding for the large-scale human safety studies that will add further momentum to research on CBD's potential applications. Impact Naturals is currently participating in one such study to determine the liver-safety profile of CBD, as well as the effects of long-term use on testosterone and drowsiness (read more about this milestone study  ).

For a bird's eye view of the state of the research today, our own Dr. Jim (James Lowder, MD, Chief Medical Officer at Impact Naturals) has given us this round-up on what notable studies in the field have to say about cannabinoids.

What hard evidence supports the use of cannabinoids to modify health? 

  • The broad expression of cannabinoid receptors throughout the body. CB1 and CB2 receptors are located on nerves (especially in the synapse), immune cells (especially macrophages and mast cells), and skin epithelial cells.
  • The expression of CB2 receptors is increased in inflammatory or trauma circumstances, influencing the production of naturally-occurring cannabinoids by the body and their local modulating activity.
  • The well-known psychotropic effects of THC.
  • The improved mental function, anti-anxiety, and anti-paranoia influence of CBD upon those unwanted effects produced by THC.
  • The endocannabinoid system is central to the production of the 'runner’s high' that can follow vigorous exercise.
  • Acetaminophen's (Tylenol's) analgesic (pain-relieving) mechanism of action is mediated through a metabolite which is a cannabinoid agonist.
  • Functional MRIs of the brain show changes in blood flows to various parts of the brain changing in response to CBD and THC (often diametrically opposed).

What cannabinoid-based prescription drugs are already FDA-approved?

CBD isolate

  • Epidiolex (Oral high-dose CBD): GW Pharmaceuticals developed naturally-derived CBD in relatively high doses (20 mg/kg) for refractory seizure disorders (Dravet syndrome) in children.

Nabiximols (Fixed-ratio combinations of THC and CBD)

  • Sativex (Oral mucosal spray 1:1): GW Pharmaceuticals developed this combination of THC and CBD, approved for use in spasticity in patients with multiple sclerosis.

THC isolate

  • Dronabinol (Nabilone): Synthetic THC approved for use in chemotherapy-induced nausea and vomiting.

A particularly useful characteristic of CBD is that it has been found to evoke neither tolerance effects nor abuse potential, and research is in the process of determining whether CBD can work in a variety of non-endocannabinoid systems in the body. This means research still has a lot of runway, and the potential applications of CBD may be more wide-ranging than we expected.  



  1. WHO White paper on CBD
  2. Shannon et al the Permanente J 2019;23:18-041
  3. Bergamaschi MM simulated public speaking 2011 36:1219-26
  4. Devinsky  Dravet syndrome NEngJMed 2017 376:2011-20
  5. Donvito NeuroPsychPharm Rev 2018
  6. Cristino et al Nature Rev 2020 V 16 p9