Potential Side Effects of Using CBD

Side Effects of CBD

Cannabidiol (CBD) has been receiving a lot of attention lately for its promising health benefits. Benefits for everything from arthritis pain, anxiety, depression, acne and many more conditions.

The benefits sound great, but most treatments include a few possible side effects. So, what are the side effects of using CBD?

If you’re skeptical about using CBD, this article may be of use. After examining the latest research, here’s everything we have discovered about the potential side effects of using CBD. Just keep in mind that good research is limited and some of this is anecdotal.

Most Common CBD Side Effects

Pure CBD Vapors

CBD doesn’t include an enormously long list of side effects, but there are some. Additionally, some of these side effects may come from Tetrahydrocannabinol (THC), rather than just CBD. A lot of the existing research on CBD is focused on cannabis, which contains both compounds.

Nevertheless, there are a few CBD side effects that remain widely known, such as:

  • Dry mouth
  • Drowsiness
  • Low blood pressure
  • Light-headedness
  • Increased appetite

CBD may inhibit salivary secretion, resulting in dry mouth. This side effect is also not surprising, as three out of four Americans are chronically dehydrated anyway.

Luckily, this appears to be one of the easiest side effects to avoid. You simply need to stay hydrated while using CBD.

Taking CBD may also make you a little sleepy, but the compound affects everyone differently. Some people feel more awake when they take CBD.

Blood Pressure

Low blood pressure is another side effect that may not impact everyone. It’s apparently only reported with high doses of CBD, but it may lead to some light-headedness.

One of the most common CBD risks is increased appetite, but it’s not necessarily a negative effect. Individuals going through chemotherapy often experience reduced appetite and CBD may help stimulate their hunger.

Less Common CBD Side Effects

Some side effects are less common but appear in the latest research. There are occasional mentions of the following issues:

  • Gastrointestinal distress
  • Upset stomach
  • Diarrhoea
  • Nausea

Gastrointestinal (GI) distress is an interesting side effect, as some research suggests that CBD may help relieve GI disorders.

The endocannabinoid system that CBD interacts with helps protect the GI tract against inflammatory bowel disease and irritable bowel syndrome. It may also reduce nausea, vomiting, and abdominal pain.

Not everyone experiences these side effects after taking CBD. In fact, many users report that CBD helps alleviate some of these issues.

Interestingly, these side effects may not come from the CBD compound. They may come from the ingredients used to deliver the compound.

If you take a CBD pill or ingest CBD oil and experience an upset stomach, the distress is more likely the result of the carrier oil and other ingredients.

People tend to report these side effects more frequently with high doses of CBD. Currently, very little research or advice exists on correct CBD dosage.

It’s also important to note that many of the reported side effects of CBD come from research involving cannabis, which also includes THC. Additionally, CBD may help counter some of the negative aspects of THC.

Potential Safety Concerns of CBD

Along with the side effects discussed, I came across a few serious safety concerns. Please pay attention to these potential CBD risks:

  • Drug interactions
  • Withdrawal symptoms
  • Increased permeability of the placental barrier
  • Liver damage

These concerns only affect certain individuals and apply to specific situations, but they do require review if you plan on using CBD.

Look Out for CBD Drug Interactions

Drug Types

Negative drug interactions are another potential concern with CBD for those that already take prescription medications.

CBD interacts with a variety of enzymes, including CYP450 enzymes found in almost every prescription medication and many over-the-counter drugs, including:

  1. Antiarrhythmics
  2. Antipsychotics
  3. Antidepressants
  4. Anti-epileptics
  5. Antihistamines
  6. Benzodiazepines
  7. Beta blockers
  8. Calcium channel blockers
  9. HIV antivirals
  10. Immune modulators
  11. NSAIDs
  12. Oral hypoglycaemic agents
  13. PPIs
  14. Prokinetics
  15. Steroids

One study found that CBD may inhibit CYP2D6 enzymes, the same enzymes targeted by warfarin and diclofenac. Warfarin is a blood thinner often prescribed to cancer patients while diclofenac is an anti-inflammatory medication.

Apparently, researchers have known about the potential drug interactions of CBD for quite some time. In 1942, researchers found that CBD prolonged the hypnotic effects of certain barbiturates.

Researchers also know that CBD inhibits enzymes that may interfere with other xenobiotics, such as THC and other medicines. Due to these potential interactions, it may not be a good idea to take CBD if you currently take any prescription medications without talking to your doctor.

Not all drug interactions are bad. I also came across an 8-week-long clinical study involving 13 children treated for epilepsy with an antiepileptic drug.

CBD interacted with specific enzymes that increased the bioavailability of the medication. After administering CBD, doctors could reduce the dose of the antiepileptic drug and its side effects.

Additionally, some researchers believe that any adverse effects of CBD may be the result of drug interactions with existing medications.

Dependency and Withdrawal

There is very little risk of addiction to CBD, but it’s possible to develop a tolerance to the chemical compounds. When people suddenly stop taking CBD, they may experience some of the side effects associated with withdrawal, such as:

  • Irritability
  • Insomnia
  • Hot flashes
  • Nausea
  • Restlessness

Interestingly, it seems that CBD may also reduce the occurrence of some of these symptoms when experiencing withdrawal from other drugs.

Withdrawal is not common, but it seems that some individuals are more sensitive to CBD than others.

As CBD affects major organs and tissues besides the brain, it may bring increased CBD risk factors for those with a sensitivity to the compound. Some of these effects include:

  • Red eyes
  • Muscle relaxation
  • Digestive distress
  • Low blood pressure
  • Fast heartbeat

When users first experience some of these effects, they may also experience anxiety or panic due to the changes in their heartbeat and blood pressure.

Increased Permeability of the Placental Barrier


For decades, doctors have advised pregnant women to avoid cannabis due to the potential for developmental effects on the baby. However, taking CBD may also impact the pregnancy.

The American Academy of Paediatrics (AAP) published a report advising pregnant women about the risk of increased permeability of the placental barrier. This increases the exposure of the fetus to other substances that the mother takes.

So, if a pregnant woman uses CBD and THC, she may expose more of the THC to her unborn baby.

Can CBD Cause Liver Damage?

Liver Anatomy

Liver damage is a common safety concern of CBD. In one study, about 10% of patients experienced increased liver enzymes. However, it’s estimated that about 30 million US citizens have some form of liver disease.

Increased liver enzymes may indicate that 10% of the patients are already suffering from some form of inflammation or liver damage.

CBD may also help heal the liver. A 2011 study found that CBD killed harmful cells known to promote the spread of liver disease.

CBD Products Remain Unregulated

A lot of people are using CBD and a lot of companies are producing products to keep up with the demand.

In this unregulated market, it’s hard to determine if you’re really getting what you pay for. Some CBD products may contain different amounts of the compound compared to the information on the label.

Seventy percent of unregulated CBD products are improperly labelled. You may get more CBD, less CBD, and even some THC.

Summary – Is CBD Safe?

Most of the research points to the same conclusion – CBD is a safe substance with limited negative effects on the human body.

It’s worth noting that some of the CBD side effects are minor and less severe compared to medications used for treating the same conditions.

For example, patients with epilepsy received CBD and some experienced diarrhoea and changes to appetite or weight. However, these effects were still minor compared to the side effects of traditional epilepsy medications.

The bottom line is that CBD appears to provide a safe option for treating a wide range of health issues with minimal risks. Just remember to talk to your doctor before taking any supplements, including CBD, that may impact your current treatment.

Image Credits: Placenta by BruceBlaus [CC BY-SA 4.0], via Wikimedia Commons, Liver by Tvanbr [Public domain], via Wikimedia Commons


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