A prescription cannabidiol (CBD) oil is considered an effective anti-seizure medication. However, further research is needed to determine CBD's other benefits and safety.

Once a holistic health trend, cannabidiol (CBD) has officially gone mainstream—14% of U.S. adults use the wellness product, according to a 2019 Gallup poll. And people use it for various reasons: 40% of people use CBD products for pain relief, 20% use them for anxiety management and 11% use them to improve sleep. But the number of product options on the market today is overwhelming, especially when it comes to CBD oil. So we’re cutting through the noise and identifying the best of the best for you.

To choose the best CBD oils of 2021, the Forbes Health editorial team analyzed data on more than 40 CBD oil products made from plants grown in the U.S.; have a certificate of analysis (COA) confirming the absence of pesticides, heavy metals and molds; are third-party tested by ISO 17025-compliant laboratories; and are organic and non-GMO. From price to potency, see which CBD oil products stand out as our top picks.

CBD is a chemical found in marijuana. CBD doesn't contain tetrahydrocannabinol (THC), the psychoactive ingredient found in marijuana that produces a high. The usual CBD formulation is oil, but CBD is also sold as an extract, a vaporized liquid and an oil-based capsule. Food, drinks and beauty products are among the many CBD-infused products available online.

Currently, the only CBD product approved by the Food and Drug Administration is a prescription oil called Epidiolex. It's approved to treat two types of epilepsy. Aside from Epidiolex, state laws on the use of CBD vary. While CBD is being studied as a treatment for a wide range of conditions, including Parkinson's disease, schizophrenia, diabetes, multiple sclerosis and anxiety, research supporting the drug's benefits is still limited.

CBD use also carries some risks. Though it's often well-tolerated, CBD can cause side effects, such as dry mouth, diarrhea, reduced appetite, drowsiness and fatigue. CBD can also interact with other medications you're taking, such as blood thinners.

Another cause for concern is the unreliability of the purity and dosage of CBD in products. A recent study of 84 CBD products bought online showed that more than a quarter of the products contained less CBD than labeled. In addition, THC was found in 18 products.

What to Look for When Choosing a CBD Oil
Because CBD oil is considered a dietary supplement and isn’t regulated by the Food and Drug Administration (FDA), consumers need to do their own research to ensure the quality of the product they choose to try. Here are a few criteria to consider when shopping for CBD oil:

U.S. sourcing. The FDA doesn’t regulate CBD oil products specifically, but it does regulate the cannabis sativa plants grown on U.S. soil, requiring that they contain no more than 0.3% THC by dry weight. (THC, or tetrahydrocannabinol, is the most well-known psychoactive compound found in the cannabis sativa plant, and some states have yet to legalize it due to its mind-altering effects.) Buying CBD oil sourced in the U.S. ensures the product you’re using meets these legal requirements.

Third-party testing. By sending samples of a product to an independent and accredited laboratory for testing, a company can ensure safety and security standards are being met, which is important for supplements like CBD oil.

Certificate of Analysis (COA) availability. This document is supplied by the third-party laboratory to confirm whether the CBD product meets the specifications advertised on its label. It also acknowledges any presence of pesticides, heavy metals or molds, which can be harmful to human health. Look for a CBD brand that transparently provides COAs for their products on their website.

How to Use It
Experts advise newcomers to start with a low dose of CBD oil, such as 25 milligrams a day, and gradually increase their dose to a level that provides the desired effects. It’s best to navigate this process under the guidance of a qualified physician, as reactions to CBD can vary per person.

If you plan to use products containing CBD, talk to your doctor.