Have you ever wondered about the difference between Epidiolex, the first cannabidiol (CBD)-based prescription medication, and the CBD oils lining store shelves? If CBD is the active ingredient in Epidiolex, how is it different from the many CBD oil products you can buy without a prescription?

Epidiolex and over-the-counter CBD products have important differences that can affect how they work for seizures. Continue reading to learn more about the differences between CBD oils and Epidiolex.

What Is CBD?

CBD is a chemical found in the Cannabis sativa plant. Although tetrahydrocannabinol (THC) is found in the same plant, CBD doesn’t make you feel “high,” like THC does. CBD is nonintoxicating.

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CBD can be isolated from either hemp or marijuana. When CBD is isolated from the plant, it can be put in products such as:

• Oils
• Capsules
• Gummies
• Creams

CBD has been studied for potential health benefits in several conditions, including:

• Anxiety
• Sleep problems
• Chronic pain and inflammation
• Addiction

The strongest evidence is for certain seizure disorders.

The U.S. Food and Drug Administration (FDA) approved Epidiolex to treat seizures associated with severe forms of epilepsy such as Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex (a condition that causes noncancerous tumors) in people age 1 and older.

8 Differences Between CBD Oil and Epidiolex

Although cannabidiol is the active ingredient in both CBD oil and Epidiolex, there are several key differences.

Epidiolex is currently the only FDA-approved CBD product available. This means that the FDA has evaluated Epidiolex for the following factors:

• How well it works for epilepsy
• Drug interactions (for instance, with other anti-seizure drugs)
• Side effects
• Safety concerns

Other CBD oils haven’t gone through the same FDA drug-approval process. The FDA hasn’t evaluated these products to determine whether they work, what dose is appropriate, how they interact with other medicines, or whether they’re safe. The FDA still regulates CBD products under other laws.

It’s legal to have and use Epidiolex with a valid prescription because it’s an FDA-approved medication. However, CBD laws vary by state.

Talk to your doctor to learn more about CBD laws in your state.

It’s important to note that you may test positive during a cannabis drug test while taking either CBD or Epidiolex. If you need a drug test, you should tell the testing center that you’re currently taking Epidiolex as prescribed by your doctor.

The dosage and how often you take CBD oil products versus Epidiolex may vary. Your doctor will determine your dose of Epidiolex based on your weight and the type of seizures being treated.

Clinical trials have studied the appropriate dosage to balance seizure control with possible side effects. It can also take time to find the right dosage for you.

A MyEpilepsyTeam member shared, “It took me a long time to get to the dosage for Epidiolex I am at.”

Your dose for other CBD oil products may not be as clear. Talk to your doctor before trying CBD oil.

Unlike Epidiolex, over-the-counter CBD products don’t have an FDA-approved dose. Your doctor can help you understand the possible risks, side effects, and drug interactions.

The side effects of a CBD oil product and Epidiolex may be different. CBD can cause side effects and interact with other medicines, but the amount of safety information may vary by product.

Possible side effects of CBD include:

• Liver damage
• Drowsiness or sleepiness
• Headache
• Diarrhea
• Changes in appetite
• Irritability or agitation

Because Epidiolex has been studied in clinical trials, much more information is available about its potential side effects. Its prescribing information lists common side effects such as:

• Sleepiness
• Decreased appetite
• Diarrhea
• Increased liver enzymes
• Tiredness and weakness
• Rash
• Sleep problems
• Fever
• Vomiting
• Infections

Epidiolex is manufactured to comply with the FDA’s strict Good Manufacturing Practices regulations. This means Epidiolex must meet strict standards for its strength, purity, quality, and consistency from batch to batch.

Additionally, the CBD used to make Epidiolex comes from hemp plants that are grown specifically to make a high amount of CBD. The CBD isolated for use in Epidiolex is highly purified.

The cannabis plants used to make Epidiolex are grown in a regulated environment and are free from:

• Pesticides
• Heavy metals
• Contaminants

Other CBD oil products don’t go through the same drug-approval process as Epidiolex. Without the same standards, products may have different amounts of CBD or have unexpected contaminants.

A 2024 study of 202 commercial CBD products found that 74 percent differed from the CBD amount listed on the label by at least 10 percent. Heavy metals, residual solvents, and pesticides were also found in some products.

An inactive ingredient is any ingredient in a drug product other than the active ingredient. Some inactive ingredients may matter if you’re following a special diet or have a food allergy.

Epidiolex doesn’t contain sugar or gluten (wheat, barley, or rye).

Inactive ingredients in Epidiolex include:

• Dehydrated alcohol
• Sesame seed oil
• Strawberry flavor
• Sucralose

Labeling may not be accurate for CBD oils sold over the counter. In a 2017 study of 84 CBD products bought online, 31 percent were accurately labeled for CBD content, and 21 percent contained THC.

A larger 2024 study also found labeling problems. Researchers reported that 46 percent of CBD products contained more CBD than the label claimed, and 28 percent contained less.

To help avoid CBD oil products with inaccurate labeling or contaminants, look for a certificate of analysis from an outside laboratory (also known as third-party testing). A certificate of analysis can give you information about the quality and purity of CBD oil.

Epidiolex is available by prescription at a specialty pharmacy with a valid prescription from your doctor. Many insurance plans may cover Epidiolex for its FDA-approved indications.

CBD oil products are not FDA-approved medications for seizures and are generally not covered by insurance plans. Unlike Epidiolex, CBD oil can be purchased in many places, including online, specialty stores, grocery stores, and gas stations in some states.

Talk to Your Doctor

Talk to your doctor to find out if Epidiolex may be a good option for you or whether it’s safe for you to try CBD oil. Always be open and honest with your doctor about everything you’re taking — including over-the-counter medications, vitamins, and other supplements like CBD oil.