DEAR MAYO CLINIC: For years, I have been hearing about the advantages of taking CBD products for sleep, pain and just about anything that ails you. I now see these products everywhere being sold over the counter in drug stores. Is CBD beneficial, and does it live up to its claims?

ANSWER: CBD is one of the main cannabinoids found in the marijuana, or cannabis, plant. Overall, more than 500 compounds and more than 100 cannabinoids are in a marijuana plant.

Products made with CBD in the U.S. retail market should not contain THC, the psychoactive ingredient in marijuana that produces a high. These products are supposed to be only derived from the marijuana strain cannabis sativa, which naturally has less than 0.3% of THC.

CBD is available by prescription commercially alone or as an added ingredient in many over-the-counter products. These products are legal at the federal level as long as the CBD is derived from a cannabis sativa plant grown in the U.S. from a company with a specially issued license. The products are illegal if derived from the higher THC-containing cannabis indica strain or a sativa plant not grown in the U.S.

Although CBD claims to have many beneficial effects, the Food and Drug Administration (FDA) classifies it under its orphan drug designation. This is a special status designation that must meet criteria of therapy for a rare disease or is used so infrequently that it may not be a profitable product because of low use or demand.

CBD has primarily been marketed as an anti-convulsant agent for rare seizure disorders, though some newer indications are being investigated.

At this time, nonprescription CBD products lack consistent oversight to ensure their purity and safety, or verify manufacturer claims. The CBD that you can buy over the counter is regulated more like herbal supplements than medications. This is because the FDA only enforces quality and safety standards if a safety issue arises once a product is on the market.

The standards for CBD products, like herbal supplements, are based on manufacturers making ethical and honest claims. You cannot rely on the amount of CBD listed on labels, unless assessed by an independent party such as the United States Pharmacopeial Convention. In addition, you cannot be assured that CBD is free from contaminants such as THC, pesticides or heavy metals.

At this time, CBD cannot be rated for any condition other than epilepsy due to lack of evidence. This is true even though it is used for, or claimed to be effective for, many other conditions.

CBD is a central nervous system depressant, so it can make you drowsy. However, its long half-life in the body of 50–60 hours makes it undesirable as a sleep aid. Half-life is defined as how long half of the drug is eliminated after one dose. Sleep aids are best suited to medications with shorter half-lives, so fatigue and drowsiness are not experienced into the next day. Other common side effects are decreased appetite, fever, increased liver function tests, anemia, fatigue and gait disturbances.

The highly touted pain relief indication of CBD has not been shown by current research.

CBD is also metabolized in a complex way by many enzymes in the body, while it interferes with other enzymes that metabolize other drugs, making CBD a substance to use carefully if you take other over-the-counter or prescription medications.

Current research indicates that CBD is not as beneficial as claimed. While research is ongoing into CBD as a treatment for a wide range of conditions, including cancer, hepatitis, Parkinson's disease, diabetes, certain rare inherited disorders and some psychiatric disorders, future indications may result in CBD not being classified as an orphan drug. Until better evidence indicates that more common uses are safe and effective, CBD will continue to be a product that lacks evidence to support claims of efficacy for many conditions.

Before you try nonprescription CBD for any medical concern, you should speak with your health care provider or pharmacist about whether it would be safe and effective for you. Also, your health provider may be able to help you determine which product to purchase. — Michael Schuh, Pharm.D., R.Ph., Pharmacy, Mayo Clinic, Jacksonville, Florida

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