Does CBD have side effects?

Growing rapidly in popularity, some people wonder about CBD’s side effects. Here’s what you need to know…


While generally well-tolerated by most people, CBD can have some side effects. Most of those could be classed as mildly annoying, while other side effects can be more problematic. Especially if you are taking mega doses (in the 600 – 1500 mg/day range).

The World Health Organization found CBD to be safe, non-toxic, and non-addicting in 2017. Further, many studies have demonstrated its antioxidant, anti-anxiety, and neuroprotective benefits.

On its own, CBD is not an intoxicant, making it one of the safest of hemp and cannabis’ phytocannabinoids. Extracted from hemp or cannabis, CBD has minimal THC. By law, the THC content must not be above 0.3% by volume. For that reason, it will not produce a psychoactive reaction.  CBD comes in different forms, topical creams and ointments, tinctures, capsules, and edibles.

Still, CBD can affect some users with niggling side effects.

Dry mouth

Taken by mouth or under the tongue, CBD can interact with CB receptors in the submandibular glands. That interaction tends to reduce saliva production, causing what is popularly known as dry or cotton mouth. Drinking plenty of water soon dispels that problem.


CBD can impact sleep, paradoxically inducing wakefulness, and drowsiness. At higher doses (160 – 600 mg), researchers have found that CBD has a positive effect on insomnia and the sleep cycle. Users reported that it was easier to fall asleep and stay asleep.

At a dose of about 15 mg, clinical researchers concluded that users experienced more alertness and wakefulness.

Low blood pressure

CBD, especially in high doses, can affect blood pressure, usually within a short time after taking. That is good news for people with hypertension and who are seeking an alternative to traditional medications. However, it can also cause temporary light-headedness if you stand up too quickly.

If you are already taking medication for hypertension, talk with your doctor before using CBD.


Diarrhea and loose stools are more annoying potential CBD side effects. Typically, they’re caused by other ingredients in the CBD, such as the carrier oil. Coconut, olive, grapeseed, and other oils are the most familiar carrier oils, and they can affect first-time CBD oil users.

If you experience diarrhea, stop taking CBD oil for 24 hours to see if that’s the cause. If so, try a lower dosage. Choose your CBD oil with care and be sure of its purity. Reputable producers provide independent lab analyses at no charge.

MCT (medium-chain triglycerides) oil is a standard carrier oil for CBD. Generally speaking, it is safe for nearly everyone. If you experience diarrhea, consider taking your CBD as an edible or lowering the dosage. In most cases, that will remedy the problem.


If you are taking high doses of CBD, you may experience feelings of fatigue. The best advice if you are feeling fatigued, is to avoid taking CBD before driving.

Hepatic drug metabolic inhibition

Hepatic drug metabolism is the mechanism by which the liver breaks down, converts, and processes most drugs, whether prescription or over-the-counter. CBD has the potential to temporarily neutralize cytochrome P-450. Cytochrome P-450 is an enzyme that’s found mostly in the liver. Its function includes processing and transporting proteins.

If you are taking prescription medications, this is an important consideration. Talk with your doctor about potential effects before beginning to take CBD.

Pay attention to vape additives in your CBD

If you vape your CBD, you could face some potentially harmful side effects. The potential for an adverse reaction lies with the different additives, such as flavorings, in your vape juice. Although the FDA recognizes artificial flavorings as generally safe, those chemical additives may pose problems.

Vegetable glycerin is often used in CBD vape juices. However, it’s possible that vaping CBD may cause an allergic reaction. People who are especially sensitive to it may experience difficulty breathing, dizziness, and nausea. Propylene glycol, another vape additive, is also regarded as generally safe. Like vegetable glycerin, some users could have an allergic reaction to it.

Topical CBD applications and their side effects

Topical applications of CBD are popular for arthritis and other conditions. Users may experience an allergic reaction. Whether the cause is specific to the emollients used or the CBD itself isn’t clear without more testing.

Who should avoid CBD?

Despite being well-tolerated and viewed as safe by the World Health Organization, there’s still only limited research on CBD’s effects. Reputable health practitioners urge caution for pregnant women, children, and people with liver problems.

It’s best practice to monitor and control liver enzymes when CBD becomes part of your routine treatment. Similarly, CBD users who have hypertension and take medication should closely monitor their blood pressure and advise their doctor that they take CBD.

CBD can interfere with the way your body processes your medication. It can slow absorption or otherwise distort the effects of your medications. Discuss your CBD regimen with your doctor.

Proper dosage of CBD can help you to avoid side effects

Many of CBD’s side effects are caused by incorrect dosage. There are no universal guidelines for how much to take. The best advice is to start at a low dose and increase slowly over time.

Dosage is also an individual calibration. People with certain conditions may take more or less CBD according to what works for them. Of note, epilepsy patients take higher doses of CBD than people with anxiety disorders.

Your CBD dose should also take your weight into consideration. Those who weigh more will require a higher dose than someone who weighs less. Dosage is calibrated by 2.5 mg per kilogram of body weight.

Choose good quality CBD

Unreliable CBD products can include high THC levels, contaminants, synthetic compounds, and even heavy metals.

Unfortunately, labeling can be inconsistent throughout the industry. Clear labeling and certification by third-party laboratories are key in determining which CBD product to use. Such labeling and verification make it possible to be sure of what you’re getting.

Data regarding CBD and its benefits and effects are still being collected. Research is gaining ground over the previous dearth of scientific information. To date, the indications are that CBD is of relatively low toxicity and safe for a majority of users. As always, consult your physician.

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