Cannabidiol (CBD)-what we know and what we don’t
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?
How is cannabidiol different from marijuana, cannabis and hemp?
CBD, or cannabidiol, is the second most prevalent active ingredient in cannabis (marijuana). While CBD is an essential component of medical marijuana, it is derived directly from the hemp plant, a cousin of marijuana, or manufactured in a laboratory. One of hundreds of components in marijuana, CBD does not cause a “high” by itself. According to a report from the World Health Organization, “In humans, CBD exhibits no effects indicative of any abuse or dependence potential…. To date, there is no evidence of public health related problems associated with the use of pure CBD.”
Is cannabidiol legal?
CBD is readily obtainable in most parts of the United States, though its exact legal status has been in flux. All 50 states have laws legalizing CBD with varying degrees of restriction. In December 2015, the FDA eased the regulatory requirements to allow researchers to conduct CBD trials. In 2018, the Farm Bill made hemp legal in the United States, making it virtually impossible to keep CBD illegal – that would be like making oranges legal, but keeping orange juice illegal.
The Farm Bill removed all hemp-derived products, including CBD, from the Controlled Substances Act, which criminalizes the possession of drugs. In essence, this means that CBD is legal if it comes from hemp, but not if it comes from cannabis (marijuana) – even though it is the exact same molecule. Currently, many people obtain CBD online without a medical marijuana license, which is legal in most states.
The evidence for cannabidiol health benefits
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.
Animal studies, and self-reports or research in humans, suggest CBD may also help with:
Studies and clinical trials are exploring the common report that CBD can reduce anxiety.
- Insomnia. Studies suggest that CBD may help with both falling asleep and staying asleep.
- Chronic pain. Further human studies are needed to substantiate claims that CBD helps control pain. One animal study from the European Journal of Pain suggests CBD could help lower pain and inflammation due to arthritis when applied to skin. Other research identifies how CBD may inhibit inflammatory and neuropathic pain, which are difficult treat.
- Addiction. CBD can help lower cravings for tobacco and heroin under certain conditions, according to some research in humans. Animal models of addiction suggest it may also help lessen cravings for alcohol, cannabis, opiates, and stimulants.
Is CBD safe?
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.
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.
How can CBD be taken?
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.
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.
The bottom line on cannabidiol
Some CBD manufacturers have come under government scrutiny for wild, indefensible claims, such that CBD is a cure-all for cancer or COVID-19, which it is not. We need more research but CBD may prove to be a helpful, relatively non-toxic option for managing anxiety, insomnia, and chronic pain. Without sufficient high-quality evidence in human studies, we can’t pinpoint effective doses, and because CBD currently is typically available as an unregulated supplement, it’s hard to know exactly what you are getting.
If you decide to try CBD, make sure you are getting it from a reputable source. And talk with your doctor to make sure that it won’t affect any other medicines you take.
The Potential Side Effects of CBD
Wendy Rose Gould is a lifestyle reporter with over a decade of experience covering health and wellness topics.
Verywell Mind articles are reviewed by board-certified physicians and mental healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more.
Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.
Verywell Mind content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication. Learn more.
Karen Cilli is a fact-checker for Verywell Mind. She has an extensive background in research, with 33 years of experience as a reference librarian and educator.
Verywell / Alex Dos Diaz
Generally speaking, CBD is considered a safe substance when applied topically or taken orally. There are, however, some potential side effects to keep in mind when using this substance, the majority of which are mild.
Common Side Effects of CBD
The most comment side effects of CBD include drowsiness, gastrointestinal issues, dry mouth, reduced appetite, nausea, and interaction with other medications. Those are outlined in detail below.
Some common side effects when using CBD include drowsiness and sedation. This is also considered a benefit, but Dr. Jas Matharu-Daley, a physician and chief medical officer for a CBD brand, notes that the effects might be too strong if you’re also taking CBD with other sedating medications.
Some people may get diarrhea or liver problems [when using CBD]. This is dependent on the individual and their medical history, so monitoring is important,” says Dr. Matharu-Daley.
Also known as “cotton mouth,” CBD can potentially cause your mouth and eyes to feel very dry. Though this side effect is more likely to occur with THC, it can happen with CBD as well.
Can Interact With Other Medications
CBD might interfere with the other medications you take. Dr. Matharu-Daley says it’s important to talk to your doctor about whether CBD could affect your existing prescriptions.
In some cases, those who ingest CBD supplements might experience nausea, says Dr. Matharu-Daley. This depends on how sensitive the person is to CBD, as well as the amount they ingest.
Because CBD supplements come in so many different forms—such as oils, gummies, tinctures, and vapors—the amount that’s actually absorbed can vary drastically. This, combined with each person, will ultimately affect which (if any) CBD side effects you might experience.
What Is Cannabidiol (CBD)?
CBD—the abbreviation for cannabidiol, a substance that’s generally derived from the hemp plant—has skyrocketed in popularity over the last five years. In fact, according to research, “CBD” as a Google search term remained stable from 2004 to 2014 but has since ballooned by up to 605%.
CBD is one of the many chemical compounds that is found in the cannabis plant—referred to as cannabis sativa. There are two primary parts of the plant that humans use. One is THC, or Delta-9-Tetrahydrocannabinol, and the other is CBD. Though they’re from the same plant, THC and CBD are quite different from each other.
“CBD is not an intoxicating substance, whereas THC is a psychoactive that can get you high,” explains Dr. Jas Matharu-Daley, a physician and consultant for a brand that specializes in CBD production.
Are There Any Benefits Associated With Using CBD?
There are several reasons why someone might want to use CBD. The substance can be found in a multitude of products ranging from pain-relieving creams to edible tinctures to skincare. Research is still underway, but over the last few decades scientists have become more aware of how CBD might be beneficial when applied either topically or ingested.
“Since discovering the endocannabinoid system (ECS) in the body in the 1990s, CBD has been researched more extensively. The ECS is a central regulatory system restoring normal balance and homeostasis in a range of human physiologic systems throughout the body and brain and has cannabinoid receptors and chemicals in its function,” explains Dr. Matharu-Daley.
CBD benefits include the following:
- CBD can have positive impact on the brain. In fact, Dr. Matharu-Daley says that the substance is legally prescribed in a specific medication for certain severe forms of epilepsy in children.
- It has also been shown to have anti-inflammatory properties, which is why you often see CBD in topical products such as oils, creams, and lotions.
- Some research points to CBD’s ability to relieve stress and anxiety.
- It has been used as a nausea treatment in some countries.
- CBD may potentially reduce pain symptoms.
- It has antioxidant properties, which means it can help fight off free radical damages that leads to premature aging.
- Regarding skincare, CBD may help reduce excessive oil production in those with very oily skin types.
Ultimately, the primary reasons why people use CBD is because it tends to have calming, relaxing, pain-reducing effects. It has been used to alleviate joint pain and nerve pain, reduce anxiety and stress, treat insomnia, improve migraines, and address nausea.
CBD Is Still an Unregulated Substance
It’s important to point out that CBD is not regulated by the FDA and therefore dosages might not be accurate. It’s also difficult to know what an appropriate dose is the first time you try a new product.
“If the CBD is from a reputable source and one that has been inspected by a third-party independent lab, the content of CBD is more reliable,” notes Dr. Matharu-Daley. “The CBD should be organically grown, free of pesticides and heavy metals, and not sourced in food which can affect absorption. Generally, CBD is safe and side effects are few at low doses.”
A Word From Verywell
CBD is technically an unregulated substance in the United States and therefore it ought to be used with caution. This is especially important for those taking additional medications and/or those with ongoing medical issues. That said, preliminary research on CBD and its benefits are promising in relation to helping with mild to moderate health concerns and it is generally considered a safe substance. Health professionals do not consider CBD a cure-all for serious medical issues, including cancer.
As with any sort of supplement, we recommend speaking to your medical doctor about whether using CBD makes sense for you. Your doctor can also recommend certain products that align with your needs and help ensure you get the correct dosage.
What Is CBD Oil?
This cannabis extract may help treat nerve pain, anxiety, and epilepsy
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.
Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more.
Meredith Bull, ND, is a licensed naturopathic doctor with a private practice in Los Angeles. She helped co-author the first integrative geriatrics textbook, “Integrative Geriatric Medicine.”
Cannabidiol (CBD) oil is an extract from hemp plants called Cannabis indica and Cannabis sativa . You might be more familiar with cannabis plants because they are grown for marijuana. However, CBD is not the same thing as marijuana.
CBD oil contains CBD that’s mixed with a base (carrier) oil, like coconut oil or hemp seed oil. These are called tinctures. You can get tinctures in different concentrations. The oil can also be put into capsules, gummies, and sprays.
People who support using CBD oil say that it can treat pain and anxiety; can help stimulate appetite and may help manage some types of seizures.
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.
CBD vs. Marijuana
CBD is one component (called a cannabinoid ) that’s found in a hemp plant. Marijuana is a separate plant but it’s from the same species that hemp belongs to. Marijuana has CBD and hundreds of other compounds in it.
The main difference between hemp plants and marijuana plants is how much of a compound called tetrahydrocannabinol (THC) is in them. Hemp is grown to have less than 0.3% THC, while marijuana has more.
THC is what’s responsible for the psychoactive effects of cannabis—in other words, it’s what makes you feel “high.”
CBD oil generally does not have THC in it; however, a very small (trace) amount might be in products sold in certain states.
What Is CBD Oil Used For?
We’re not sure exactly how CBD works. Unlike THC, CBD doesn’t have a strong connection with the molecules in the brain that THC binds to create psychoactive effects. These are called cannabinoid receptors.
Instead, CBD works on other receptors, like the opioid receptors that help control pain. It also affects glycine receptors that control a brain chemical called serotonin which helps control your mood.
People that support the use of CBD claim that CBD oil can treat a variety of health problems, including:
- Chronic pain
- Drug use and withdrawal
- High blood pressure
- Muscle spasms
- Poor appetite
As CBD has gained popularity, researchers have been trying to study it more. Still, there has not been a lot of clinical research to look for evidence in support of these health claims.
CBD is not a safe option for everyone. Talk to your healthcare provider if you want to try it for managing a health condition.
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 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.
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 studies 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.
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.
In June 2018, the U.S. 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. That said, more research is needed to understand the link.
Possible Side Effects
Clinical research has shown that CBD oil can cause side effects. The specific side effects a person has and how bad they are varies from one person to the next and from one type of CBD to another.
Some common side effects people report from using CBD include:
- Changes in appetite
- Changes in mood
- Dry mouth
CBD oil may also increase liver enzymes, which is a marker of liver inflammation.
People with liver disease should talk to their healthcare provider before taking CBD oil. They may need to have their liver enzymes checked regularly if they are using CBD.
Can You Use CBD If You’re Pregnant?
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.
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.
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. That said, never change or stop medication without talking to your provider.
Dosage and Preparation
There are no guidelines for using CBD oil. Each product works a bit differently, depending on the form.
For example, putting the oil under your tongue can produce effects more quickly than swallowing a capsule that needs to be digested.
Here are a few ways that you can take CBD oil:
- Placing one or more drops under your tongue and holding it there for 30 to 60 seconds without swallowing. You can also use a spray that is spritz in your mouth/under your tongue.
- Taking a capsule or chewing a gummy
There’s no “correct” dose of CBD oil. How much you take and the form you choose will depend on your needs and what you hope to get for effects. The average dose range is from 5 mg to 25 mg.
Most oils come in 30-milliliter (mL) bottles and include a dropper cap to help you measure.
That said, it’s hard to figure out the exact amount of CBD per milliliter of oil. Some tinctures have concentrations of 1,500 mg per 30 mL, while others have 3,000 mg per mL or more.
How to Calculate CBD Dose
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. The math to figure that out looks like this: 1,500 mg ÷ 600 drops = 2.5 mg
What to Look For
CBD oil comes in different forms: isolates, broad-spectrum, and full-spectrum.
- Isolates contain only CBD
- Broad-spectrum oils nearly all of the components of the plan (e.g., proteins, flavonoids, terpenes, and chlorophyll), but does not have THC 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.
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 to keep in mind:
- 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: Even if you choose a full-spectrum oil, 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.
Hemp plants can be grown for different purposes. Some species are made for marijuana but others are used to make CBD products.
Unlike marijuana, CBD oil does not “get you high.” Instead, it may help relieve stress, anxiety, drug withdrawals, and nerve pain.
While there are many claims about the health benefits of using CBD oil, the evidence is lacking. A lot of studies were done with animals, not humans.
If you want to try CBD oil, you should learn about the different dosages and preparations first.
You should also know that the products are not regulated, which means you can’t know for sure that a product will work and be safe.
Before you use CBD oil, talk to your provider. If you take certain medications or have a health condition, you may not be able to use these products.
Frequently Asked Questions
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.
It depends on where you live, the type of product, how it was sourced (e.g., is it from hemp or marijuana), 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.
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.