How Safe is CBD?

Claire Viscione, National Center for Health Research


Cannabis, a substance in marijuana, is becoming more and more mainstream across the U.S., and a related substance is also on the rise: CBD. Cannabidiol (CBD) is an ingredient in cannabis and hemp that has taken the public by storm. CBD products are divided into three classifications: CBD with less than 0.3% THC, CBD with more than 0.3% THC, and pharmaceutical CBD.[1] The only CBD product that is approved by the FDA is Epidiolex, an anti-seizure medication for children who suffer from severe, rare forms of epilepsy.[2] 

Companies have included CBD as a main ingredient in food, beverages, and beauty products[3]. Many products are also advertised as being “CBD-infused.”[3] CBD is sold in oil, extract, capsule, and vapor forms.[3] Products like lotions, gummies, soap, and dog treats are found almost everywhere, from gas stations to retailers to news-stands.[4] Some celebrities have even endorsed CBD products. Sales of CBD products are expected to reach $2 billion by 2022.[1] But the FDA says that other than Epidiolex, no CBD products are approved for medical purposes. 

What is CBD?

CBD is an active ingredient in Cannabis sativa, or hemp, plants that is not considered to have effects typically associated with the “high” of marijuana.[5] These plants are classified based on their THC concentration. THC is the active ingredient in marijuana that gives users the feeling of being “high.”[3] Plants with less than 0.3% of THC are often just referred to as hemp. Plants with more than 0.3% of THC are known as cannabis. CBD can come from either.[5]

CBD products are marketed as helping increase relaxation, decrease anxiety, and as having anti-inflammatory qualities.[6] However, there is no scientific evidence behind these claims. One study showed that over half of the people currently using CBD products say they use them to treat medical conditions like pain, anxiety, and depression.[7] However, making medical claims for a product requires FDA approval based on clinical trials proving safety and effectiveness, which CBD does not have. It can be sold as a dietary supplement, but only if it does not claim to improve health.[1] 

Are CBD products legal?

The THC concentration in CBD is important in determining whether or not it is legal. If CBD comes from the hemp plant with less than 0.3% THC, then it is legal under federal law.[1] If CBD has more than 0.3% THC, it is considered cannabis and is illegal on a federal level. The Drug Enforcement Administration (DEA) considers these products with more than 0.3% THC to be Schedule 1 controlled substances, meaning they have no accepted medical use and a high potential for abuse.[5] 

Even though CBD is legal if it contains less than 0.3% THC, it is illegal to buy or sell any CBD product interstate.[5] Buying CBD in one state for use in a different state violates the Food, Drug, and Cosmetic Act. However, you can purchase most products with less than 0.3% THC in-state, and if you live in the District of Columbia or one of 33 states you can legally buy higher-concentration CBD if you are over 21.[5]

The 2018 Farm Bill legalized the sale of hemp (with less than 0.3% THC) and its extracts, meaning that this is no longer regulated on a federal level.[1] Because CBD with less than 0.3% of THC is not regulated, manufacturers do not have to prove that their products are safe or effective before they sell them, as long as they do not make claims about the possible benefits.[1] Since the government has not enforced restrictions on marketing, this helps explain why there has recently been a surge in products with hemp-based CBD. 

Current Research

The FDA has concluded that CBD has benefits that outweigh risks for the epilepsy drug Epidiolex. This is based on studies of patients with Dravet syndrome and Lennox-Gastaut syndrome (LGS).[8] These two childhood epilepsy syndromes typically do not respond to anti-seizure medications.[8] The FDA approved Epidiolex based on 4 double-blind placebo-controlled trials showing that CBD oil could significantly reduce the number of seizures that participants were having.[9] If you have been using any CBD product besides Epidiolex to treat epilepsy, stop taking it and consult a doctor to find out if the product is safe and consistent with your symptoms.

Animal studies suggest that CBD might be effective in treating pain management and disorders like schizophrenia, PTSD, and phobias.[10] Some researchers even hope that CBD could help with substance abuse disorders and addiction cravings.[11] However, there is not enough research in humans to support those claims, or claims that CBD helps people “relax” more than just a placebo effect. Some human trials also looked at CBD to treat anxiety, but these trials are also too small and short-term to show effectiveness.[5] The FDA has allowed researchers to study CBD in humans since 2015, but the information currently available is mostly limited to animal trials.[12] 

Concerns About CBD

The benefits of CBD are not proven, but the risks seem to be clear. Reported side effects of CBD products may include fatigue, drowsiness, reduced appetite, dry mouth, and diarrhea.[3] Some research in animals has shown that CBD could also harm your liver and central nervous system.[13] Not enough is known about CBD to fully understand how it can interact with medications. Experts warn not to consume CBD products if you are on medications such as blood thinners.[3]

Another concern is unreliable labeling. A 2018 study of CBD products sold online revealed that more than a quarter of the products examined contained less CBD than labeled, and some of these products also contained more THC than advertised.[6] Another study found that 9 out of 14 samples of CBD products had “notably different” concentrations than the amount on their label.[6] The uncertainty of the actual content of CBD products may increase risks. In 2019, the Food and Drug Administration (FDA) sent four warning letters to the biggest CBD manufacturers, all of whom had incorrectly labeled the amount of CBD in their products and/or had falsely claimed that their products could cure diseases such as cancer and Alzheimer’s.[14]

Bottom Line

It is possible that CBD could benefit people with several different symptoms, but there is currently no concrete, scientific evidence other than for pediatric epilepsy. Before deciding whether to take CBD supplements, talk to your doctor to determine how CBD may affect you, and be aware that the advertising claims for most CBD products are unproven. The FDA is encouraging more clinical research to understand the science behind CBD and how it could be used in the future, but it currently remains a complicated issue. 

Learn more about the FDA’s stance on CBD. 

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.

References:

  1. Federation of American Scientists. FDA Regulation of Cannabidiol (CBD) Products. FAS.org. https://fas.org/sgp/crs/misc/IF11250.pdf. Published June 12, 2019.
  2. US Food and Drug Administration. FDA approves first drug comprised of an active ingredient derived from marijuana to treat rare, severe forms of epilepsy. FDA.gov. https://www.fda.gov/news-events/press-announcements/fda-approves-first-drug-comprised-active-ingredient-derived-marijuana-treat-rare-severe-forms. Published June 25, 2018.
  3. Bauer BA. What are the benefits of CBD — and is it safe to use? MayoClinic.org. https://www.mayoclinic.org/healthy-lifestyle/consumer-health/expert-answers/is-cbd-safe-and-effective/faq-20446700. Published December 20, 2018.
  4. Florko N. An introduction to CBD — and what Washington might do about it. StatNews.com. https://www.statnews.com/2019/06/18/introduction-to-cbd/?utm_source=STAT+Newsletters&utm_campaign=f0b735f239-Daily_Recap&utm_medium=email&utm_term=0_8cab1d7961-f0b735f239-151560461. Published June 18, 2019.
  5. Rubin R. Cannabidiol products are everywhere, but should people be using them? JAMA. 2019; 322(22): 2156-2158. https://jamanetwork-com.proxygw.wrlc.org/journals/jama/fullarticle/2756099
  6. Pavlovic R, Nenna G, Calvi L, Panseri S, Borgonovo G, Giupponi L, … Giorgi A. Quality traits of “cannabidiol oils”: Cannabinoids content, terpene fingerprint and oxidation stability of European commercially available preparations. Molecules. 2018; 23(5): 1230. https://www.mdpi.com/1420-3049/23/5/1230
  7. Corroon J, Philips JA. A cross-sectional study of cannabidiol users. Cannabis Cannabinoid Research. 2018; 3(1): 152-161. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6043845/
  8. Samanta D. Cannabidiol: A review of clinical efficacy and safety in epilepsy. Pediatric Neurology. 2019; 96: 24-29. https://www-clinicalkey-com.proxygw.wrlc.org/#!/content/playContent/1-s2.0-S0887899418311688?returnurl=null&referrer=null 
  9. US Food and Drug Administration. Drug trials snapshots: Epidiolex. FDA.gov. https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshots-epidiolex. Updated July 17, 2018.
  10. Blessing EM, Steenkamp MM, Manzanares J, Marmar CR. Cannabidiol as a potential treatment for anxiety disorders. Neurotherapeutics. 2015; 12(4): 825–836. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604171/
  11. Hurd YL, Yoon M, Manini AF, et al. Early phase in the development of cannabidiol as a treatment for addiction: Opioid relapse takes initial center stage. Neurotherapeutics. 2015; 12(4): 807–815. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604178/
  12. Grinspoon P. Cannabidiol (CBD) — what we know and what we don’t. Health.Harvard.edu. https://www.health.harvard.edu/blog/cannabidiol-cbd-what-we-know-and-what-we-dont-2018082414476. Published August 24, 2018. Updated August 27, 2019.
  13. Huestis MA, Solimini R, Pichini S, et al. Cannabidiol adverse effects and toxicity. Current Neuropharmacology. 2019; 17(10): 874-989. https://www.ncbi.nlm.nih.gov/pubmed/31161980
  14. US Food and Drug Administration. FDA warns company marketing unapproved cannabidiol products with unsubstantiated claims to treat cancer, Alzheimer’s disease, opioid withdrawal, pain and pet anxiety. FDA.gov. https://www.fda.gov/news-events/press-announcements/fda-warns-company-marketing-unapproved-cannabidiol-products-unsubstantiated-claims-treat-cancer. Published July 23, 2019.