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.
Cannabidiol Use in Older Adults
ABSTRACT: Cannabidiol (CBD) is a nonpsychoactive component of the Cannabis sativa plant. CBD products, which have become popular in the United States, are frequently used to treat pain, anxiety, and sleep disorders—conditions that affect older adults. Evidence is insufficient to recommend the use of CBD for these disease states. OTC CBD products are widely available, and there are significant concerns regarding their safety, including mislabeling, standardization issues, and drug interactions. The informed pharmacist will be a valuable resource for discussing the use and safety of CBD with older adults.
Cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) are among the many cannabinoids, or components, of the Cannabis sativa plant. CBD is nonpsychoactive, whereas THC has psychoactive properties such as euphoria and psychosis. Two common strains of Cannabis sativa are marijuana and hemp. 1 CBD may be derived from either marijuana (which often contains more than 15% THC) or hemp (having a THC concentration of no more than 0.3%). 2 In addition, CBD may be extracted from Cannabis indica and hybrid plants, which may have higher concentrations of CBD than THC. A recent survey revealed that one in seven Americans uses CBD products, with the most common reasons for its use being pain, anxiety, poor sleep, and arthritis. 3
Endogenous cannabinoids and phytocannabinoids such as CBD and THC modulate the endocannabinoid system (ECS). THC is a partial agonist on the cannabinoid (CB) 1 receptor that results in central nervous system (CNS) effects, such as the “high” associated with marijuana; it also has limited CB2 agonist activity in the immune system. CBD has minimal activity on CB receptors, but it affects the ECS and the non-ECS. 4 Some of the proposed mechanisms of CBD include agonist activity at serotonin 1A, transient receptor potential vanilloid 1, G protein–coupled receptor 55, and adenosine A2A receptors, which may explain some of the possible analgesic, anti-inflammatory, anxiolytic, and antiepileptic effects of CBD. 1,5
In the United States, about two-thirds of states have legislation approving cannabis for recreational use (11 states) and/or medicinal purposes (21 additional states). Seven states mandate pharmacist involvement, such as dispensing activities or consulting to dispensaries. 6 The only FDA-approved (in 2018) CBD product is Epidiolex, which is indicated for treatment of seizures associated with Lennox-Gastaut syndrome or Dravet syndrome. 7 The law prohibits the sale of foods or dietary supplements to which CBD has been added; however, a wide variety of products containing CBD are available at retail stores. 8
CBD formulations used in clinical trials include oral capsules, sublingual spray, oil-based solution, and topical gel. OTC CBD products are available in numerous other formulations, including topical balms and creams, e-liquid for inhalation, and infused foods and drinks. 1,9 Given the many formulations and manufacturers, nearly all CBD products lack standardization. The exception is Epidiolex, which is available as an oil-based oral solution formulated with sesame oil and standardized to contain 100 mg/mL of pure CBD extract. 7
CBD levels in commercially available products vary widely. The FDA has issued warning letters every year since 2015 to companies marketing unapproved new drugs that allegedly contain CBD. 8,10-13 As part of these warnings, the FDA tests the chemical content of CBD compounds, and it has found that many products do not contain the claimed level of CBD. Commercially available products have been assessed in laboratories, whose findings support the FDA’s concerns about product inconsistency and mislabeling. A laboratory assessment of OTC CBD products sold in the U.S. demonstrated that only 26 of 84 (31%) products tested were accurately labeled. 14 Not only was the amount of CBD in products overlabeled or underlabeled, but 21% of products contained THC even though it was not listed in the product information. In addition, the FDA has cited concerns regarding reports of contaminants such as pesticides and heavy metals. 8
The mislabeling of CBD products results in dosing uncertainty in the use of any commercially available OTC product. This is an important caveat in the extrapolation of dosages used in clinical research. In such research, a range of dosages have been used for different indications and routes of administration. For example, Epidiolex oral solution is approved for weight-based dosing from 5 mg/kg/day to a maximum of 20 mg/kg/day. 7 CBD has been given orally at dosages of 100 mg to 800 mg. 15,16 CBD topical gel has been used for fragile X syndrome at a dosage of 50 mg to 250 mg daily. 17 For smoking cessation, a CBD metered-dose inhaler has been administered at a dosage of 400 mcg as needed. 18
Administration and Absorption
CBD absorption depends on the product formulation. In animal and human studies, CBD administered orally has been shown to be poorly absorbed, with bioavailability of 13% to 19%. 19,20 CBD’s bioavailability is believed to be reduced by first-pass metabolism. Poor bioavailability can be avoided with the use of alternative formulations. There is an emerging market for novel delivery methods to increase CBD’s oral bioavailability. 21
Absorption of CBD may also be altered by food intake. In clinical trials, coadministration of Epidiolex with a high-fat, high-calorie meal increased plasma levels of CBD fourfold to fivefold compared with administration on an empty stomach. 7 In one study using a purified (99%) CBD capsule, coadministration with food resulted in a maximum concentration and AUC of 14-fold and fourfold higher, respectively, compared with administration on an empty stomach. 22 CBD inhalation in humans has an average bioavailability of approximately 31%, with the use of one type of metered-dose inhaler demonstrating bioavailability of more than 65%. 18,23 Transdermal absorption of CBD is variable in animal studies and has yet to be fully elucidated in humans. 4
CBD is FDA-approved for certain types of seizure disorders; for more information, see the manufacturer’s website for Epidiolex (www.epidiolex.com). The following section will focus on the common reasons for off-label CBD use, including pain, sleep disorders, and anxiety, all of which affect older adults.
Pain: An estimated 50 million American adults (20.4%) experience chronic pain, with persons aged 65 years and older constituting 61.2% of those affected. 24 Much of the data on chronic pain (e.g., neuropathic pain, cancer pain, diabetic peripheral neuropathy, fibromyalgia, HIV-associated sensory neuropathy, spasticity associated with multiple sclerosis [MS], and rheumatoid arthritis) involve the use of marijuana and cannabinoids (often THC, combination THC-CBD, or nabiximols [a specific mixture of THC, CBD, other minor cannabinoids, flavonoids, and terpenes]). Formulations used in pain studies range from smoked, oral, or oromucosal spray of THC; synthetic cannabis (nabilone); synthetic THC (dronabinol); and vaporized cannabis, with results suggesting modest reductions in pain and spasticity. 25
Sativex (nabiximols), an oromucosal THC-CBD spray, is approved in several European countries for treating symptoms of moderate-to-severe spasticity associated with MS, and a phase II/III clinical trial is currently under way in the U.S. to evaluate nabiximols for advanced cancer pain with inadequate analgesia from chronic opioids. 26 There is a paucity of data on CBD used for pain; most studies are in preclinical stages. 5,25,27
Sleep Disorders: Sleep disorders are disproportionately more prevalent in older adults. 28 Patients have commonly reported that cannabis is helpful for sleep. 29 CBD is used for alleviation of insomnia, but little is known about its effectiveness. One study that compared CBD with placebo for insomnia in 15 patients suggested that 160 mg of CBD may improve sleep duration without next-day sedation. 30 Somnolence was reported in nearly one-third of patients taking Epidiolex in clinical trials, which provides additional support for CBD’s benefits for sleep in some patients. 7 However, more research is needed to determine whether CBD is useful for individual components of insomnia, such as sleep latency, wakefulness after sleep onset, sleep duration, and overall sleep quality.
Anxiety: Evidence is not strong for the use of CBD for anxiety disorders. CBD has demonstrated some benefit for social anxiety disorder and social phobia when patients undergo a simulated public-speaking test. 31,32 However, these trials had small sample sizes and study biases. It is theorized that CBD could be beneficial for anxiety based on its mechanism of action at the serotonin receptor. 31
Other Disease States: Data on the use of CBD for various other conditions are mixed, and evidence is insufficient to recommend this practice. The efficacy of CBD has been studied in bipolar disorder, Crohn’s disease, diabetes, dystonia, fragile X syndrome, graft-versus-host disease, Huntington’s disease, opioid withdrawal, Parkinson’s disease, schizophrenia, and smoking cessation. 33 In addition, CBD has been reported to be useful for addiction, possibly by modulating dopamine and serotonin. 1
Adverse Effects and Safety
The use of CBD is considered “possibly safe” when used appropriately, based on some clinical evidence. 33 However, insufficient high-quality data exist to recommend CBD for most older adults. The most common adverse effects associated with CBD, reported in clinical trials of Epidiolex, are somnolence (~32%), decreased appetite (16%-22%), diarrhea (9%-20%), and increased liver-function tests (13%). 7 Other side effects are orthostatic hypotension, lightheadedness, and dry mouth. Adverse effects appear to be dose-related. The safety of CBD in the geriatric population has not been fully clarified, and Epidiolex clinical trials did not include patients older than 55 years. 7
There are practical concerns regarding CBD use in older adults. The geriatric population may be more susceptible to adverse effects of CBD commonly seen in younger adults, including sedation. CBD is hepatically metabolized, predominantly via CYP2C19 and CYP3A4. 4 Older adults with reduced hepatic function may be more susceptible to adverse effects of CBD.
Commercially available CBD products may not contain the CBD concentrations claimed on the label, and the FDA warns consumers to be aware of this inconsistency when using such products. 13 Of particular concern is the THC component in mislabeled CBD products. Older adults may be predisposed to adverse effects caused by the psychoactive properties of THC. The use of marijuana in older adults has been associated with increased risk of injury and adverse events. 34
CBD has been shown to inhibit hepatic enzymes. 4 In human studies, coadministration of CBD with antiepileptic drugs resulted in increased concentrations of drugs that are substrates of CYP2C9, CYP2C19, and CYP3A4. 35 Given CBD’s known sedative effect, there is also a theoretical concern for additive hypnotic reactions in combination with CNS depressants. TABLE 1 lists potential interactions with CBD.
The Pharmacist’s Role
A recent survey by the Arthritis Foundation revealed significant use of and interest in CBD for arthritis. The Foundation acknowledges the possible efficacy of CBD for treating pain, insomnia, and anxiety while also recognizing the lack of rigorous clinical studies. 36 Despite a scarcity of evidence for CBD use in the geriatric population, education on known and potential benefits and risks is vital to a patient’s decision-making process. The pervasive direct-to-consumer advertising and ubiquity of CBD products may foster misinformation or misinterpretation of actual evidence. The pharmacist should be prepared to give an unbiased assessment of CBD, including concerns about product mislabeling, underlabeling and overlabeling of CBD, and lack of THC labeling in a product containing it.
The pharmacist should consider patient-specific factors when discussing CBD use. A review of potential drug-drug interactions is warranted prior to using CBD. Counseling on pharmacokinetic variables, such as oral administration with or without food, may be relevant. Comorbidities may also be pertinent to the discussion, and safety concerns should be reinforced. For example, a patient with preexisting respiratory disease should avoid inhalation as the route of CBD administration. An honest and impartial discussion will facilitate a stronger patient–healthcare provider relationship.
If a patient has decided to use CBD, the pharmacist can direct the patient toward a top-quality CBD product. TABLE 2 provides questions to consider when recommending a CBD product. Given the increasing number of states and U.S. territories legalizing marijuana for medicinal or recreational use, the informed pharmacist will be a valuable resource for discussing the use and safety of CBD with older adults. 6