People taking high doses of CBD may show abnormalities in liver related blood tests. Many non-prescription drugs, such as acetaminophen (Tylenol), have this same effect. So, you should let your doctor know if you are regularly using CBD.
A significant safety concern with CBD is that it is primarily marketed and sold as a supplement, not a medication. Currently, the FDA does not regulate the safety and purity of dietary supplements. So, you cannot be sure that the product you buy has active ingredients at the dose listed on the label. In addition, the product may contain other unknown elements. We also don’t know the most effective therapeutic dose of CBD for any particular medical condition.
Side effects of CBD include nausea, fatigue and irritability. CBD can increase the level of blood thinning and other medicines in your blood by competing for the liver enzymes that break down these drugs. Grapefruit has a similar effect with certain medicines.
Is CBD safe?
Cannabidiol (CBD) is often covered in the media, and you may see it touted as an add-in booster to your post-workout smoothie or morning coffee. You can even buy a CBD-infused sports bra. But what exactly is CBD? And why is it so popular?
CBD has been touted for a wide variety of health issues, but the strongest scientific evidence is for its effectiveness in treating some of the cruelest childhood epilepsy syndromes, such as Dravet syndrome and Lennox-Gastaut syndrome (LGS), which typically don’t respond to antiseizure medications. In numerous studies, CBD was able to reduce the number of seizures, and, in some cases, stop them altogether. Epidiolex, which contains CBD, is the first cannabis-derived medicine approved by the FDA for these conditions.
The evidence for cannabidiol health benefits
Outside of the US, the prescription drug Sativex, which uses CBD as an active ingredient, is approved for muscle spasticity associated with multiple sclerosis and for cancer pain. Within the US, Epidiolex is approved for certain types of epilepsy and tuberous sclerosis.
CBD comes in many forms, including oils, extracts, capsules, patches, vapes, and topical preparations for use on skin. If you’re hoping to reduce inflammation and relieve muscle and joint pain, a topical CBD-infused oil, lotion or cream – or even a bath bomb — may be the best option. Alternatively, a CBC patch or a tincture or spray designed to be placed under the tongue allows CBD to directly enter the bloodstream.
Sex was associated with sexual enhancement where males reported experiencing more sexual enhancement (9.9%) than females (2.9%) (aOR 0.274, [95% CI 0.11–0.70], p = 0.007). There were no other associations between sex and other CBD benefits. Those aged 55+ (23.1%; aOR 3.8, [95% CI 1.63–8.87], p = 0.002) and those aged 35–54 years old (16.8%; aOR 2.72, [95% CI 1.258–5.876], p = 0.011) reported taking less of their other medications in comparison to those aged under 34 years old (9.9%). Those ages 55+ reported experiencing more “no positive experiences” (14.3%) in comparison to those under 34 (2.7%; aOR 5.31, [95% CI 1.45–19.41], p = 0.012).
When used in high doses, somnolence is a primary adverse effect (Machado Bergamaschi et al. 2011). Patients in CBD clinical trials were more likely to experience sedation (OR 4.21, 95% CI 1.18–15.01) and somnolence (OR 2.23, 95% CI 1.07–4.64) in comparison to placebo (Chesney et al. 2020). Despite this preclinical and experimental research, there is a lack of human clinical trials to establish the efficacy and appropriate CBD indications fully. The effective dose for most of the above indications is still to be determined. In much of the research, high doses of CBD are used (between 300 and 1200 mg), whilst at the same time, globally, millions of CBD users are using low dose CBD. Thus, a disconnect exists between clinical research and the current state of the market.
Corroon et al. found a more even distribution between various application methods with the most popular being sublingual CBD (23% vs 72,6% in our study sample). Our approach of recruiting respondents through email databases of non-vape CBD brands may explain why the sublingual administration route is much more frequent in our study than in the American survey.
Amongst our study sample, almost 11% experienced having a dry mouth, most likely indicating levels of THC in the product, as this is a common side effect of THC rather than CBD (Darling and Arendorf 1993; LaFrance et al. 2020). People living outside of the UK had higher odds of experiencing a dry mouth, which might be explained by the different legislation regarding permitted THC content and CBD quality between countries. This differentiation leads to some concerns about product safety, consistency, and ultimately trust amongst CBD consumers. A recent study of 29 CBD products showed that only 11% contained within 10% of the advertised CBD concentration, 55% of the products had traces of controlled substances such as THC (Liebling et al. 2020). There is still a need for external and internal control within the CBD industry to ensure consumer safety is prioritised.
A cross-sectional study of 2409 cannabidiol users from the USA found that the top three medical conditions reported were chronic pain, arthritis/joint pain, and anxiety, followed by depression and insomnia (Corroon and Phillips 2018). A recent survey carried out by Wheeler et al. of 340 young adults, some of whom were CBD users, found the top reasons to be stress relief, relaxation, and sleep improvement. They found edible CBD products to be the most prevalent (Wheeler et al. 2020). Another study of 400 CBD patients in New Zealand observed an increase in overall quality of life, a decrease in perceived pain, depression, and anxiety symptoms, as well as an increase in appetite and better sleep (Gulbransen et al. 2020).
Our measures were retrospective self-reported symptoms, rather than contemporaneous reports or object assessments, and thus prone to recall bias. This approach may lead to over- or under-estimation of benefits and harms. In reporting anxiety symptoms, it should be noted that many anxiety measures are self-reported, and scales are often an accurate measure of anxiety. Stress itself is not often measured, but scales assessing self-reported stress are reliable (Morgan et al. 2014). Regarding sleep problems, our measures do not accurately correspond with objective measures of sleep such as actigraphy (Girschik et al. 2012), which has implications in the epidemiology of sleep, including in the present study. Future research should use validated measures of anxiety, stress, and sleep. However, it should be noted we included responses to gain an insight where CBD may not help, with about 20% responding that CBD did not help with sleep or anxiety and about 10% saying CBD did not help with stress. There is also a risk of selection biases regarding our recruitment method from email databases of current users and social media recruiting. As we had a self-selected sample, we do not represent the general population or even the overall population of CBD users. It is more likely that respondents with a positive experience have responded to this survey, and continue to use CBD. Still, users with a negative experience may have stopped using CBD and therefore were not reached by this survey, which might further contribute to the selection biases.
Reasons for cannabidiol use amongst 397 adult cannabidiol users who were allowed to respond to more than one option leading to a total of 1622 responses. Y-axis represents percentage based on total responses
The Cannabis plant has been cultivated and used for its medicinal and industrial benefits dating back to ancient times. Cannabis sativa and Cannabis indica are the 2 main species.1 The Cannabis plant contains more than 80 different chemicals known as cannabinoids. The most abundant cannabinoid, tetrahydrocannabinol (THC), is well known for its psychoactive properties, whereas cannabidiol (CBD) is the second-most abundant and is nonpsychoactive. Different strains of the plant are grown containing varying amounts of THC and CBD. Hemp plants are grown for their fibers and high levels of CBD that can be extracted to make oil, but marijuana plants grown for recreational use have higher concentrations of THC compared with CBD.2 Industrial hemp must contain less than 0.3% THC to be considered legal, and it is from this plant that CBD oil is extracted.3
Kathleen Louden, ELS, of Louden Health Communications provided editorial assistance.
Descriptive statistics for anxiety and sleep scores among adults using cannabidiol treatment