Cannabidiol (CBD) oil contains CBD, a natural chemical derived from cannabis. According to data from more than 45,000 people who took the International Cannabis Policy Survey, CBD oil is the most popular way to consume CBD.

Many CBD-infused products boast of benefits ranging from relief of anxiety, pain, insomnia, and menstrual cramps to clearing your skin, staving off aging, and bulking up your bones. But scientific research is less clear on whether cannabis oil reliably provides these health boons.

People can take cannabis oil in several different ways.

1. Swallowing CBD oil: CBD passes through the digestive system when swallowed, and is metabolized by the liver. This sends its active compounds throughout the body over several hours. People often consume CBD oil in drops, tinctures, and capsules, or added to foods and beverages, such as gummy candies and coffee. People can also take CBD as a powder that manufacturers produce by removing all plant matter to create a crystalline substance that has no taste or odor.

2. Drops of CBD oil under the tongue: Another popular way to take CBD is to place a few drops of the oil or tincture, or a small bit of the powder, under the tongue and hold it there for several seconds. This allows the bloodstream to rapidly absorb the active ingredients into the bloodstream through the mucous membranes in the mouth.

3. Vaporizing and inhaling CBD oil: People can inhale CBD by vaporizing the oil or by adding the oil to e-cigarettes or tobacco and smoking them. Inhaled CBD enters the bloodstream rapidly through the lungs, avoiding the digestive system. For this reason, “vaping” has been a popular way of using CBD. But a mysterious series of lung injuries linked to inhaling products has led the Centers for Disease Control and Prevention (CDC) to urge people to refrain from vaping while they investigate. Most of the people in the more than 800 cases reported by the end of September 2019 were in patients who used products containing THC, according to the CDC. Like CBD, THC is a cannabinoid, and the two often occur together in vaping products.

4. Applying CBD oil to the skin: People can rub CBD-infused products such as oils onto the skin, which may help relieve pain and reduce inflammation directly where necessary. Topical products include creams, salves, patches, shampoos, suppositories, lip balms, bath salts, and personal lubricants.

No, you can’t get blissed out on CBD alone. Its chemical cousin, THC, is the only cannabinoid that causes the high associated with cannabis use. For this reason, it’s important to know exactly what type of CBD you’re buying.Marijuana-derived CBD oil comes from high-THC cannabis plants, which can contain varying amounts of THC. (Packing typically lists the ratio of CBD to THC on the product label.) Any product with more than 0.3 percent THC is considered a controlled substance and can only be bought in a state where medical or recreational cannabis is legal. Some people consume marijuana-derived cannabis oil that producers extract using this same process.Although the science is scant, very limited research reported that some experts believe combining CBD with THC enhances CBD’s pharmacological benefits, a theory known as the “entourage effect.”

Hemp-derived CBD oil comes from low-THC cannabis plants. This is the type of CBD nutrition stores and supermarkets sell over the counter in nutrition stores, cool coffee shops add to lattes, and luxe beauty product manufacturers infuse into creams.

Because it’s not intoxicating, hemp-derived CBD is behind most commercially available CBD products. Health stores are now embracing what once was called “hippie’s disappointment” precisely because it can induce the relaxing effects of marijuana without impacting your consciousness or ability to function in daily life, explains the psychologist Lara Fielding, PsyD, the author of Mastering Adulthood: Go Beyond Adulting to Become an Emotional Grown-Up.

“I’ll confess, I tried CBD, and my whole life I’ve been an adamant antidrug person because people I’ve known and loved have ruined their lives with drugs,” Dr. Fielding says. “And I’ve been converted. It triggered a wonderful feeling of going from tension and pain and distress to feeling fine without altering me in any other way.”

CBD interacts with the endocannabinoid system, a large messaging network in your body that plays a key role in regulating many physiological functions. In fact, cannabinoids are so essential to good health that your brain produces its own.

According to a review, cannabinoids interact with the following crucial functions:

• Appetite, digestion, and metabolism

• Mood, memory, and sleep

• Motor control

• Saliva and tear production

• Pain perception

• Immune function (including inflammation)

• Heart and lung function

The strongest scientific evidence of CBD’s efficacy in humans is for reducing seizures in two rare types of epilepsy that occur in children: Dravet syndrome and Lennox-Gastaut syndrome. Based on that evidence, a liquid CBD anti-seizure drug, cannabidiol (Epidiolex), obtained approval from the U.S. Food and Drug Administration (FDA) in June 2018.The National Center for Complementary and Integrative Health (NCCIH) has found that current research also supports CBD’s potential for reducing nausea and vomiting after chemotherapy treatment and managing weight and appetite loss for people with advanced HIV. A small body of evidence suggests CBD may provide slight benefits for those living with chronic pain or the effects of multiple sclerosis (MS).

On the other hand, the NCCIH does not single out CBD oil as an effective form of delivery for these conditions. The studies also included sprays, capsules, and other medications.

No studies have shown that CBD is harmful, says Debra Jaliman, MD, the author of Skin Rules: Trade Secrets From a Top New York Dermatologist. While research into CBD’s usefulness in skin-care products is admittedly limited, some facts point to its potential benefits. “CBD has been shown to be rich in amino acids, [which] provide nutrients to nourish the hair, skin, and nails,” Dr. Jaliman notes. “CBD’s also a powerful antioxidant. Antioxidants protect the skin by limiting the production of free radicals, which can damage skin cells. And CBD contains fatty acids, which help in keeping the skin healthy.”

In a 2023 survey, people most commonly reported using CBD for anxiety, depression, and chronic pain.

Although the FDA has not approved using CBD to treat any of those conditions, there are signs CBD could be beneficial. Interestingly, over 70 percent of those in the study found that it helped symptoms in some way, while less than 2 percent responded that CBD made it worse. 

1. Anxiety While no large-scale clinical trials have tested CBD oil as a treatment for generalized anxiety disorder, social anxiety, panic disorder, or phobias, a small study published in 2019 showed promising results.

During the two-month study, 72 adults in a psychiatric clinic received CBD oil capsules once daily. Most received 25 milligrams (mg) of CBD, with a few receiving doses as high as 175 mg. Within the first month, more than 79 percent of the patients reported feeling calmer, and they continued to feel calmer for the duration of the study. “We saw no evidence of a safety issue that would limit future studies,” the researchers added.

2. Depression A study showed that CBD induces “sustained antidepressant-like effects in mice.” The researchers put this effect down to a possible change in how the connections between brain cells, known as synapses. It isn’t clear whether these effects carry over for human use. More research is necessary.

“The animal data are very promising for a number of conditions, but rigorous randomized clinical trials have yet to be done,” says Kevin Hill, MD, an addiction psychiatrist and a professor at Harvard Medical School in Boston. “That is one of the frustrating aspects of the current state of cannabis: There are many companies and states profiting from the sale of cannabis and cannabinoids, but those same companies and states are not putting financial resources toward advancing the science.”

3. Pain Research has found that CBD may reduce pain symptoms, improve sleep quality, and reduce inflammation in people with some conditions that can cause chronic pain. But a randomized, controlled trial has since found that oral CBD doesn’t significantly improve short-term pain relief when a person takes it along with acetaminophen and may increase the risk of adverse effects.

There are many reasons to be cautious when buying CBD. The main factor to keep an eye on is CBD content.

A study of 63 products in the United Kingdom, including 29 oils, found that few contained an amount of CBD that was within 10 percent of the advertised figure. Usually, the product contained less than the packaging claimed. This may mean that some manufacturers don’t maintain a high standard of production or that CBD content might degrade over time.

Speak to a doctor before using CBD oil or other CBD products. They can direct you toward reputable, reliable brands with robust production processes.

“CBD by itself appears to be relatively safe,” advises Dr. Hill. “But a relatively safe substance can be dangerous if labels are not accurate or if patients elect to use CBD to treat medical conditions instead of first- or second-line treatments with far more evidence.”

Importantly, poor-quality CBD can trigger troubling, dangerous consequences. The U.S. Army, for example, issued a public health alert in September 2019 after 450 were seen at medical centers across the country for health problems, many of which had links to tainted CBD vape oils.

A 2019 review of adverse effects noted that most studies into the side effects of CBD focused on treatments for Lennox-Gastaut or Dravet’s syndromes. The researchers identified the most common adverse effects as:

• Sleepiness

• Sedation

• Fatigue

• Tiredness

• Feeling unwell

Not everyone may tolerate CBD oil well. But so far, no major problems or health scares have surfaced. Widespread use is still in its early stages, and more research is necessary.

With the passage of the 2018 Farm Bill, CBD oil derived from low-THC hemp is now legal in every state. Previously, it was a controlled substance because federal law didn’t differentiate CBD derived from hemp from CBD derived from high-THC cannabis plants.

But there’s a catch: Because CBD was approved as the active ingredient in prescription Epidiolex, the FDA regards it as a drug, making it illegal to sell OTC as a dietary supplement or in food and beverages.

As with many trends, one factor spurring demand for CBD is a slew of celebrity endorsements. Those who have spoken publicly about their use include the This Is Us actor Mandy Moore, who revealed that she used a $60 Lord Jones CBD oil to keep her feet from aching when she wore stilettos to the Golden Globes.

A-lister Jennifer Aniston claims to take CBD, too. “CBD helps with pain, stress, and anxiety. It has all the benefits of marijuana without the high,” she told Us Weekly in 2019.

CBD may have benefits for some people, but people with certain allergies, mental health issues, or underlying health problems should steer clear of CBD oil and other CBD products. These may include:

• People who have liver disease or worsening liver damage, as higher doses of CBD can cause more liver damage than lower doses

• People who take certain medications that risk liver damage, including leflunomide, lomitapide, and valproate

• People who take medications with sedative effects, such as opioid pain relief or benzodiazepines, as CBD can cause more sleepiness

• People with a history of mood disorders, suicidal thoughts, or depression

• People who have had or currently have a substance or alcohol use disorder, as CBD may still have addictive properties despite not causing a “high”

There’s no clear data on how long CBD oil takes to have an effect on pain, anxiety, seizures, or any other use for which evidence backs it. But a 2021 review found that CBD has a half-life of 18–32 hours, meaning that around half of the CBD leaves the body within this time and it becomes far less likely to have an effect.

Its speed and effectiveness may vary depending on:

• The condition or health problem you’re taking CBD to manage

• The concentration of CBD in the oil

• How long a course lasts

• Other ingredients in the oil

• The dosage and delivery method

• Other medications a person is taking along with CBD, for example for MS

CBD oil is not psychoactive, meaning that a person will not feel a high when they consume CBD oil. But people who do not tolerate CBD well or who are taking too high a dosage might feel some noticeable side effects, including:

• Drowsiness

• Sleepiness

• Decreased appetite

• Diarrhea

• Agitation or irritability

Reducing the dosage or stopping use should resolve these side effects.

Project CBD

Started by two journalists covering medical cannabis, Project CBD offers a wealth of information on the therapeutic uses of CBD, including a Beginner’s Guide on CBD dosage.

WayofLeaf

This site produces an annual guide to the best CBD oil brands, as well as reviews of various oils. They also have tips on how to find medical cannabis doctors and dispensaries near you, and state-by-state guides on how to get a medical cannabis card.