The methodological quality of randomized controlled trials (RCTs) was assessed using the Cochrane risk of bias tool . If all domains were judged as being at low risk of bias, the study was considered at low risk of bias. If at least one domain was rated high, the study was considered at high risk of bias. In situations that differ from those described above, the study was considered at unclear rick of bias. Data extraction and risk of bias was assessed by two independent reviewers and disagreements were solved by a third reviewer or with consensus.
In addition to its good safety profile and the lack of psychoactive effects, CBD presents also a wide range of therapeutic effects . Possibly for these reasons, CBD is currently one of the most studied cannabinoids . Several experimental in vitro and in vivo studies have shown that CBD has a broad range of therapeutic applications, displaying anti-inflammatory and immunomodulatory properties , anti-psychotic , analgesic  and anti-epileptic  effects, among others. Compared to Δ9-THC, CBD shows low affinity for cannabinoid receptor type 1 (CB1) and type 2 (CB2) . CB1 receptors are mainly found in the terminals of central and peripheral neurons and CB2 receptors mainly in immune cells . Several in vitro studies have shown that CBD, at low concentrations, has weak CB1 and CB2 antagonistic effect . It has also been reported that it behaves as a negative allosteric modulator of CB1, meaning that CBD does not activate the receptor directly but alter the potency and efficacy of orthosteric ligands of this receptor: Δ9-THC and 2-arachidonoylglycerol (2-AG) . These preliminary results need further validation, but may explain the ability of CBD to antagonize some of the effects of Δ9-THC reported in in vitro, in vivo and clinical human studies . It has also been suggested that the role of CBD as an allosteric modulator of CB1 can explain its therapeutic role in the treatment of central and peripheral nervous system disorders . CBD has also shown to have a strong inhibition effect of neutrophil chemotaxis and proliferation. In addition, it may induce stimulation of arachidonic acid release, reducing prostaglandin E2 (PGE2), and nitric oxide (NO) production. Furthermore, CBD reduces the expression of specific interleukins (IL-12 while increasing that of IL-10) by macrophages, and decreases the production and release of pro-inflammatory cytokines, such as IL-1, IL-6 and interferon gamma (IFNγ) from lipopolysaccharide (LPS)-activated microglial cells . The role of CBD as an inverse agonist of CB2 receptor may explain its known anti-inflammatory effects but this needs further investigation. There is also evidence of an antagonistic effect of CBD at the novel cannabinoid receptor G protein-coupled receptor 55 (GPR55), emerging from in vitro and in vivo studies. GPR55 has a role in bone physiology via regulating osteoclast function, formation and ultimately bone mass. CBD may affect the endocannabinoid system also indirectly, for example CBD can affect the endocannabinoid tone by increasing availability of anandamide; one possible mechanism is by inhibition of fatty acid amide hydrolase (FAAH), the enzyme that hydrolyzes the endocannabinoid anandamide .
Data collection and critical appraisal
We identified 362 studies of which 85 were assessed for full-text eligibility ( Fig. 1 ). Finally, 25 studies were included: 22 controlled clinical trials and three non-controlled (single arm) trials [10-34]. Among controlled clinical trials, two were non-RCTs and 20 RCTs (14 individually randomized parallel group trial, five individually randomized cross-over trials and one cluster randomized cross-over trial). Studies were conducted in five countries with the majority of studies being conducted in the UK. All studies were reported in full length journal articles. The administration of CBD varied from single doses to chronic administration, up to 48 weeks. The pure form of CBD was used in the majority of the studies except for two studies using seed CBD oil and CBD-rich botanical extracts. The most common form of drug administration was in the form of oral capsules, and other forms were vaporization and sublingual oil. The most common comparator was placebo only one study used an active-control group. Results for controlled clinical trials and non-controlled studies are presented in Table 1 [17-37] and Table 2 [38-40], providing a summary of the included studies and their principal findings.
Considering data from in vitro and in vivo studies, cannabidiol (CBD) seems to be a promising candidate for the treatment of both somatic and psychiatric disorders. The aim of this review was to collect dose(s), dosage schemes, efficacy and safety reports of CBD use in adults from clinical studies. A systematic search was performed in PubMed, Embase and Cochrane library for articles published in English between January 1, 2000 and October 25, 2019. The search terms used were related to cannabis and CBD in adults. We identified 25 studies (927 patients; 538 men and 389 women), of which 22 studies were controlled clinical trials (833 patients) and three were observational designs (94 patients) from five countries. Formulations, dose and dosage schemes varied significantly between studies. Varying effects were identified from the randomized controlled trials (RCTs), more apparent effects from non-RCTs and minor safety issues in general. From the controlled trials, we identified anxiolytic effects with acute CBD administration, and therapeutic effects for social anxiety disorder, psychotic disorder and substance use disorders. In general, studies were heterogeneous and showed substantial risks of bias. Although promising results have been identified, considerable variation in dosage schemes and route of administration were employed across studies. There was evidence to support single dose positive effect on social anxiety disorder, short medium-term effects on symptomatic improvement in schizophrenia and lack of effect in the short medium-term on cognitive functioning in psychotic disorders. Overall, the administration was well tolerated with mild side effects.
Questions about dosage and using CBD are common, especially to new users. You can always call us at (800) 563-0187, click the live chat button on the bottom right, visit our Help Center, or email us at [email protected] Whatever questions or help you need, we’re here for you.
This image shows the data we’ve collected & noticed from years of using CBD and also data from GW Pharmaceuticals.
In the case of CBD, side effects are very minimal, so that’s not a reason for someone to microdose. However, for healthy people looking for just overall health wellness, then microdosing is something to consider. Microdosing CBD is also great if you’re looking to take it during the day but not feel any effects of drowsiness, even the slightest.
While bodyweight does play a role in determining your optimal dosage, there are other factors, so the answer is no. This is mainly because everyone’s Endocannabinoid System is different regarding how sensitive your body is to cannabinoids. Some people may weigh less but have a high tolerance, while others might weigh heavier but have a lower tolerance.
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CBD consumers must learn to use a process called titration or slowly increasing their dose over time until they get the results they desire. While high doses are well tolerated, less is more. We recommend trying our CBD Product Finder Quiz as we designed a straightforward and fast quiz in bringing the best product to you as if you called and asked.
If you need help choosing what product is best for your needs, make sure to try our Product Finder Quiz. In less than 30 seconds, you’ll answer three simple questions that will show you products tailored to what you need.
If you notice it is less effective than before, do this:
Three Tips on CBD Dosing
Day 3-5: 7.5-10mg 1-2 times per day
Some people find that keeping a journal is very useful in finding the best optimal dose of CBD because they’re tracking how they feel. Keep it simple and straight to the point. When you notice it was very effective and not as much anymore, then it means you’re building tolerance, so lower your dose slightly.