Generally, CBD is considered a safe, well-tolerated substance with a low risk of abuse. Medical authorities such as the WHO (World Health Organization) deem CBD to have a good safety profile. Although most people experience positive effects from using CBD, others report mild side effects.

Some common side effects of CBD include drowsiness, dry mouth, reduced appetite, headache, and dizziness. Some CBD users also experience diarrhea and nausea. Let’s discuss these side effects and understand their causes and effects.

What Is CBD?

CBD (Cannabidiol) is one of the chemical compounds found in the cannabis plant (cannabis sativa). Before CBD became popular, people mostly viewed cannabis as a recreational drug and associated it with the psychotropic compound THC. CBD’s lack of psychotropic effects and reputed health benefits have made it an appealing supplement to millions worldwide.

How Serious Are the Side Effects of CBD?

Although it lacks the psychoactive component of cannabis, CBD can produce side effects in some users. The majority of these reactions are mild rather than serious side effects. Even everyday supplements, minerals, and vitamins run the risk of minor side effects. That said, CBD may also interact with some medications. Let’s discuss some of the potential side effects of CBD below.

Changes to Appetite

CBD seems to have varying effects on appetite. In some people, the molecule may speed up the metabolism and make them hungrier. In others, the cannabinoid seems to suppress appetite, potentially leading to weight loss.

The findings of a study published in Epilepsy & Behavior established that 13% of 117 parents of epileptic children administered with CBD-enriched cannabis extract reported a significant increase in their child’s appetite.


man experiencing fatigue at work

Many users report feeling relaxed after taking CBD. Vaping CBD products or taking CBD oil can help you unwind after a long day, but some users experience fatigue rather than a relaxed feeling.

Some people who take CBD in the morning before starting their day or during the day when they’re a bit stressed report feeling a bit more tired than usual. Research has yet to explain why this happens. It’s likely the state of fatigue stems from being in a deep state of relaxation.

Interestingly, anecdotal reports claim reduced fatigue in people suffering from chronic fatigue syndrome (CFS) following CBD administration. Since you may experience fatigue as a side effect, consider taking CBD in the evenings when you first try it. That way, you can doze off safely at home if you start to feel a bit exhausted.

Dry Mouth

The sensation of a dry mouth can occur for various reasons, ranging from consuming cannabis with high THC levels to dehydration. Some users also experience dry mouth following CBD use. This side effect results from an absent or reduced flow of saliva.

Both CBD and THC can cause this feeling. This is because THC binds to CB1 receptors and inhibits the production of saliva. CBD, however, doesn’t bind to CB1 receptors. Instead, it increases the levels of anandamide, which then binds to the CB1 receptor, resulting in a similar outcome.


Headaches are not a common side effect of CBD, but some users experience mild headaches after using it. This side effect seems to arise primarily in new users that take too much CBD too soon. Headaches may result from various other variables such as stress, certain foods, and dehydration. You want to rule out all these factors before settling on CBD as the cause of a headache.

Contrarily, CBD also shows positive results in treating people with chronic headaches. When used together with THC, CBD appears to increase serotonin levels, consequently reducing headaches.


Some users report an upset stomach or diarrhea after consuming CBD. Although the molecule causes a stomach upset in some users, it may not always be the direct culprit. If you take almost any supplement on an empty stomach, you could experience queasiness, nausea, and diarrhea.

Experiment to find when CBD has the best effects for you. Try to take CBD shortly after a meal or right before you eat to determine if you’re better off taking it with a full belly. It also helps to note that almost all CBD products contain other components. Full-spectrum CBD extracts contain several molecules like terpenes. Crude formulas also contain waxes, lipids, and chlorophyll that may contribute to an upset stomach.

CBD oil uses carriers such as coconut oil and olive oil to dilute the product, but these rarely cause any stomach issues. However, some product lines use medium-chain triglyceride (MCT), which can cause diarrhea in some people, especially if they’re new to CBD.

A 2018 study published by the journal Epilepsia documented diarrhea as an adverse reaction following the administration of CBD. The study tracked the effects of long-term CBD treatment in patients with Dravet syndrome.


woman feeling dizzy at a clinic

Dizziness is a relatively rare side effect of CBD that remains poorly understood. Several studies report dizziness as an adverse reaction after administering CBD alongside THC. Unfortunately, the cannabinoid that truly underpins these effects remains unknown.

No study, so far, digs deep into the reason why this might occur. Some scientists believe that dizziness may result from a change in the brain cells that activates the autonomic nervous system to alter blood flow to the brain. It seems THC is the main culprit for dizziness, but consuming too much CBD may also cause unease.

Lower Blood Pressure

This side effect is one of the more serious CBD reactions. It may serve as a relief in individuals with high blood pressure, but it can cause adverse reactions in those with a history of low blood pressure. Side effects such as lightheadedness and even fainting can be dangerous.

A study conducted in the United Kingdom in 2017 established that a dose of CBD lowered resting blood pressure in healthy volunteers. Even more intriguing, it reduced blood pressure increase in stressed individuals. Thus, people who suffer from anxiety attacks or high blood pressure may find CBD to be an effective natural solution.

While CBD might not be suited for some people, it could be beneficial for others. To avoid any adverse effects, always consult your doctor before using any CBD product or supplement.

Interactions with Other Medications

CBD changes the way the body metabolizes some medications. While it doesn’t directly interact with other chemicals in the blood, it changes the way the liver breaks them down. The liver plays a fundamental role in the human body, helping to activate enzymes, metabolize macronutrients, and filter blood. The liver also manufactures certain enzymes that break down drugs and end their effects in the body.

Will CBD Side Effects Go Away?

Side effects from CBD will usually dissipate quickly. All drugs have a half-life – how long it takes for their levels in the body to reduce by half. CBD’s half-life remains unconfirmed as different studies yield varying results. Although it takes a while for CBD to leave the system, its effects start to wane after about four to six hours.

How to Limit the Side Effects From CBD

buying cbd oil in a reputable website

The following tips can help you reduce the chances of encountering side effects from CBD.

Buy High-Quality CBD Oils

Thanks to CBD’s ever-growing popularity, brands have saturated the CBD market. As a result, the market has countless players selling all types of CBD products. Although many reputable companies sell high-quality oils, others sell sub-par products that haven’t been through necessary testing.

Opting for high-quality products from reliable companies will reduce the chances of experiencing the side effects of using CBD. A reputable seller will have detailed labels that state what’s in their products.

Start Low and Slow

Everyone experiences different effects from CBD. If you’ve just started using the cannabinoid, consider starting with a low, single dose to give your body time to get accustomed to it. Then slowly increase the amount and frequency as you get used to it.

Once you get the hang of it, you’ll know just how much to take before you start experiencing any unpleasant side effects.

Seek Natural Ingredients

Unfortunately, not all hemp plants are equal. Some are not grown safely or responsibly, and the final product may contain harmful chemicals from pesticides. Check that the company you purchase from uses naturally cultivated hemp featuring low THC levels.

Purchase Tested CBD Products

Trusted companies batch-test their CBD products because they have confidence in them. Only purchase products that have been batch-tested before being sold. This ensures high-quality oil free from contaminants such as adverse levels of THC and heavy metals.

The Bottom Line

Most people who use CBD encounter no side effects at all and experience only enjoyable and clear-headed effects. However, should you begin to experience any side effects, especially after taking any form of medication, consult your doctor for professional advice. Your doctor will help you determine if CBD is the right choice for you.

There need to be a lot more studies conducted to help us truly understand the effects of CBD, and many of its mechanisms remain undisclosed or unidentified.