CBD Oil Benefits vs. Side Effects

While it may be helpful, it may not be safe for all

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CBD oil is said to have a variety of possible health benefits. It is used as an appetite stimulant, a sleep aid, a treatment for skin conditions like eczema and psoriasis, for relief of pain, to prevent seizures, and much more.

Though derived from cannabis, the same plants grown for marijuana, CBD oil is not he same as pot. But that doesn't mean that CBD oil is 100% safe. Some possible side effects, like dry mouth, may be fairly minor. Others, like anxiety, are potentially more significant. And certain potential side effects may even make using CBD oil inadvisable for some people.

This article goes over what CBD is used for, the possible side effects, and what you should look for if you choose to buy CBD.

What Exactly Is CBD Oil?

CBD oil is a hemp plant extract known as cannabidiol mixed with a base (carrier) oil like coconut oil or hemp seed oil. CBD oil comes from Cannabis indica and Cannabis sativa plants.

CBD Oil Benefits

People who support the use of CBD claim that CBD oil benefits people with a variety of health problems. CBD oil is said to be good for:

As CBD has gained popularity, researchers have been trying to study it more. Still, there has not yet been a lot of clinical research focused on finding evidence to back up these health claims.

Here's a deeper dive into what is known about a few of the purported health benefits of CBD oil.

Conditions that CBD oil may help to improve
Verywell / Brianna Gilmartin

Anxiety

A 2015 review of research that was published in the journal Neurotherapeutics suggested that CBD might help treat anxiety disorders.

The study authors reported that CBD had previously shown powerful anxiety-relieving effects in animal research—and the results were kind of surprising.

In most of the studies, lower doses of CBD (10 milligrams per kilogram, mg/kg, or less) improved some symptoms of anxiety, while higher doses (100 mg/kg or more) had almost no effect.

The way that CBD acts in the brain could explain why this happens. In low doses, CBD might act the same as the surrounding molecules that normally bind to the receptor that "turns up" their signaling. However, at higher doses, too much activity at this receptor site could produce the opposite effect.

There have not been many trials to look at CBD's anxiety-relieving effects in humans. However, one was a 2019 study published in the Brazilian Journal of Psychiatry.

For the study, 57 men took either CBD oil or a sugar pill with no CBD in it (placebo) before a public-speaking event.

The researchers assessed the participants' anxiety levels using measures like blood pressure and heart rate. The researchers also used a reliable test for mood states called the Visual Analog Mood Scale (VAMS).

The men who took 300 milligrams (mg) of CBD oil reported less anxiety than the men who were given a placebo; however, the men who took 100 mg or 600 mg of CBD oil did not experience the same effects.

Addiction

CBD oil might help people with substance use disorder, according to a 2015 review published in the journal Substance Abuse.

The review looked at the findings from 14 published studies. Nine of the studies looked at the effects of CBD on animals and five looked at the effects on humans.

The researchers reported that CBD showed promise for treating people with opioid, cocaine, or psychostimulant use disorders.

However, the effects of CBD were quite different depending on the substance. For example, CBD without THC did not decrease withdrawal symptoms related to opioid use.

On the other hand, it did reduce drug-seeking behaviors in people using cocaine, methamphetamine, and other similar drugs.

Some experts suggest that CBD could help treat cannabis and nicotine dependence, but more research is needed to provide this theory.

Skin Conditions

Some studies have suggested that CBD oil may benefit the skin.

A 2020 paper, for example, found that CBD oil may help reduce inflammation, which could be useful for treating a variety of skin conditions including allergic dermatitis, acne, and psoriasis. 

Cancer

Proponents say CBD oil has benefits for people with cancer. Although some studies have shown promise, there have been no large studies proving the benefits of CBD oil as a cancer treatment.

Other studies suggest that CBD might interact with cancer drugs.

If you have cancer and are considering CBD, talk to your oncologist first about whether or not it is safe for you to use. 

High Blood Pressure

A 2017 study found that CBD oil may reduce the risk of heart disease because it can lower high blood pressure in some people.

For the study, nine healthy men took either 600 mg of CBD or the same dose of a placebo. The men who took CBD had lower blood pressure before and after experiencing stressors like exercise or extreme cold.

The study also looked at the amount of blood remaining in the heart after a heartbeat (stroke volume). The stroke volume in the men who took CBD was lower than in was in the placebo group, meaning their hearts were pumping more efficiently.

The study suggested that CBD oil could be a complementary therapy for people with high blood pressure that is affected by stress and anxiety.

However, there is no evidence that CBD oil can treat high blood pressure on its own or prevent it in people at risk. While stress can complicate high blood pressure, it does not cause it.

Sleep

Proponents say CBD oil has benefits as a sleep aid, but research so far is inconclusive.

A 2017 review pointed out that many studies have been small and limited. However, the authors also noted that because cannabinoids seem to have an effect on the sleep-wake cycle, their potential as a sleep aid is worthy of additional research.  

Seizures

In June 2018, the Food and Drug Administration (FDA) approved a CBD oral solution called Epidiolex.

Epidiolex is used to treat two rare forms of epilepsy in children under the age of 2: Dravet syndrome and Lennox-Gastaut syndrome. These are very rare genetic disorders that cause lifelong seizures starting in the first year of life.

Other than for these two disorders, CBD's effectiveness for treating seizures is not known. Even with Epidiolex, it's not clear if the anti-seizure effects are from CBD or another factor.

However, there is some evidence that CBD interacts with seizure medicines like Onfi (clobazam) and raises their concentration in the blood. More research is needed to understand the link.

Possible CBD Oil Side Effects

Clinical research has shown that CBD oil can cause side effects. The specific side effects and their severity varies from one person to the next and from one type of CBD to another.

Some common CBD side effects people report include:

  • Anxiety
  • Changes in appetite
  • Changes in mood
  • Diarrhea
  • Dizziness
  • Drowsiness or fatigue
  • Dry mouth
  • Nausea
  • Vomiting

Do not drive or use heavy machinery when taking CBD oil—especially when you first start using it or switch to a new brand. Remember that some products do contain THC, even in small amounts.

Special Concerns

Your healthcare practitioner may advise against using CBD oil if you:

  • Have liver disease: CBD oil may increase liver enzymes, which is a marker of liver inflammation. Talk with your healthcare provider before taking CBD oil. You may need to have your liver enzymes checked regularly if you decide to use it.
  • Have eye issues: CBD oil may also cause eye-related side effects. A 2018 study found that it may increase pressure inside the eyes. For people with glaucoma, this can make the condition worse. Some people also report dry eyes as a side effect of CBD oil.
  • Are pregnant or nursing: You should not use CBD oil if you're pregnant or breastfeeding. Even though the effects of CBD are not fully understood, it does pass through the placenta.

The American Academy of Pediatrics (AAP) further states that pregnant people should not use marijuana because of the potential risks to a developing fetus.

Can CBD Oil Get You High?

CBD oil does not get you high. Although it is from a plant that is in the same family as the marijuana plant, it does not contain tetrahydrocannabinol (THC), the compound responsible for this feeling.

 CBD Oil Marijuana
A component of the hemp plant Separate plant in the hemp family that contains CBD and hundreds of other compounds.
No or trace amounts of THC  Significant amounts of THC
Works receptors in the brain, but not those that induce psychoactive effects (e.g., opioid receptors that help control pain, glycine receptors that impact mood control) THC binds to cannabinoid receptors in the brain to create "high" feeling

What CBD Oil Can Interact With

CBD oil can interact with medications, including many that are used to treat epilepsy. One of the reasons for this has to do with how your body breaks down (metabolizes) drugs.

Cytochrome P450 (CYP450) is an enzyme your body uses to break down some drugs. CBD oil can block CYP450. That means that taking CBD oil with these drugs could make them have a stronger effect than you need or make them not work at all.

Drugs that could potentially interact with CBD include:

  • Anti-arrhythmia drugs like quinidine
  • Anticonvulsants like Tegretol (carbamazepine) and Trileptal (oxcarbazepine)
  • Antifungal drugs like Nizoral (ketoconazole) and Vfend (voriconazole)
  • Antipsychotic drugs like Orap (pimozide)
  • Atypical antidepressants like Remeron (mirtazapine)
  • Benzodiazepine sedatives like Klonopin (clonazepam) and Halcion (triazolam)
  • Immune-suppressive drugs like Sandimmune (cyclosporine)
  • Macrolide antibiotics like clarithromycin and telithromycin
  • Migraine medicine like Ergomar (ergotamine)
  • Opioid painkillers like Duragesic (fentanyl) and alfentanil
  • Rifampin-based drugs used to treat tuberculosis

Always tell your healthcare provider and pharmacist about all the medicines you take, including prescription, over-the-counter (OTC), herbal, or recreational drugs.

The interactions between these medications and CBD are often mild and you might not have to change your treatment. However, in some cases, you might have to change medications or space out your doses to avoid a reaction. Never change or stop medication without talking to your provider.

What's a Safe Dosage of CBD Oil?

There are no guidelines for use, nor is there a "correct" dose of CBD oil. That said, the average dose range is from 5 mg to 25 mg.

Available forms include:

  • Tinctures (CBD oil mixed with a base oil)
  • Capsules
  • Gummies
  • Sprays

Which you choose largely comes down to your preference and what you hope to get in terms of effects. For example, putting the oil under your tongue can produce effects more quickly than swallowing a capsule that needs to be digested.

Each product works a bit differently, depending on the form, so it's important to follow the provided directions.

How to Calculate a CBD Dose

Sprays, gummies, and capsules are easy to use because their doses are pre-measured.

Tinctures are a bit more challenging. Most oils come in 30-milliliter (mL) bottles and include a dropper cap to help you measure.

But some tinctures have concentrations of 1,500 mg per 30 mL, while others have 3,000 mg per mL or more. That means figuring out the exact amount of CBD per milliliter of oil requires a little math.

To determine an exact dose of CBD, remember that each drop of oil equals 0.05 mL of fluid. This means that a 30-mL bottle of CBD oil will have about 600 drops in it.

If the concentration of the tincture is 1,500 mg per mL, one drop would have 2.5 mg of CBD in it (1,500 mg ÷ 600 drops = 2.5 mg).

Safer Buying Practices

Remember that CBD oils are unregulated. There's no guarantee that a product is what it claims to be on its packaging. You also can't know for sure that it's safe and effective.

A 2017 study reported that only 31% of CBD products sold online were correctly labeled. Most had less CBD in them than was advertised, and 21% had significant amounts of THC.

If you are interested in buying CBD products, here are a few tips that can help you make the best choice:

  • Buy American: Domestically produced CBD oil might be a safer option than those that have been imported.
  • Go organic: Brands certified organic by the U.S. Department of Agriculture (USDA) are less likely to expose you to pesticides and other harmful chemicals.
  • Read the product label: Don't assume that every ingredient on the product label is natural. CBD products can also have preservatives, flavorings, or thinning agents in them. If you don't recognize an ingredient, ask the dispenser what it is or check online.

Frequently Asked Questions

  • Is one type of CBD oil better than another?

    CBD oil comes in different forms:

    • Isolates contain only CBD.
    • Broad-spectrum oils have nearly all of the components of the plant (e.g., proteins, flavonoids, terpenes, and chlorophyll), but do not have THC.
    • Full-spectrum oils have all the compounds including THC (up to 0.3%)

    Alternative medicine practitioners believe that the compounds provide more health benefits, but the is a lack of evidence to support these claims.

  • Are CBD oil and hemp oil the same?

    Not necessarily. While the names are sometimes used interchangeably, hemp oil can also refer to hemp seed oil, which is used for cooking, food production, and skincare products. CBD oil is made from the leaves, stems, buds, and flowers of the Cannabis indica or Cannabis sativa plant. It should contain less than 0.3% THC. Hemp oil is made from the seeds of Cannabis sativa and does not have TCH in it.

  • Is it possible to overdose on CBD oil?

    It would be hard to overdose on CBD oil. Research has shown that human tolerance for CBD is very high. One study reported the toxic dose would be about 20,000 mg taken at one time.

  • How old do you have to be to buy CBD oil?

    It depends on where you live, the type of product, how it was sourced, and its intended purpose (medical or recreational). In many states, you must be 18 or 21 to buy CBD oil. Check your state's laws.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Cathy Wong
Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.