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ConsumerLab.com Answers
Question: Is CBD (cannabidiol) helpful and safe? Is it legal?
Answer:
Efficacy:
Cannabidiol (CBD) is a compound derived from cannabis (a hemp plant also known as marijuana). However, unlike other compounds found in cannabis, such as THC, cannabidiol is not believed to be a psychoactive compound affecting perception, and behavior. Preliminary evidence suggests CBD may modestly reduce anxiety, certain measures of dystonia (a movement disorder), and glaucoma (Health Canada 2013).
A placebo-controlled clinical trial found a high daily dose of CBD (20 mg per kg of body weight, i.e., hundreds of milligrams) to reduce the frequency of convulsions in a rare form of epilepsy known as Dravet syndrome in children and young adults, although it was also associated with a higher rate of adverse effects including diarrhea, vomiting, fatigue, pyrexia, somnolence, and abnormal results on liver-function tests (Devinsky, New Eng J Med 2017). Similarly, the same high daily dose reduced the number of drop seizures among people with treatment-resistant Lennox-Gastaut syndrome in a 3-month study. Seizures per month decreased 44% with CBD compared to 22% with placebo; however, again, those taking CBD also had a higher rate of adverse effects including diarrhea, somnolence, fever, decreased appetite, and vomiting (Thiele, Lancet 2018).
A study of high-dose CBD (1,000 mg per day) among adults with schizophrenia found that adding CBD rather than placebo to existing treatments for six weeks reduced psychotic symptoms and caused a trend, although not statistically significant, toward improved performance on cognitive tasks. In this study, CBD was given in two divided doses (morning and evening) and was well tolerated with no increase in adverse effects (McGuire, Am J Psy 2017).
Legality:
Although CBD is not psychoactive, it is not permitted to be sold an ingredient in dietary supplements, as the FDA considers it an investigational new drug. (Note: If an ingredient is marketed as a supplement prior to the FDA authorizing its investigation as a drug, it may continue to be marketed as a supplement, but this was not the case with CBD, according to the FDA). Two conditions for which CBD has been or is being investigated as a new drug are cancer pain and, as noted above, Dravet syndrome (view a list here of completed, ongoing, and planned studies with cannabidiol). In Canada, cannabidiol is a controlled substance.
Despite the fact that CBD cannot be legally sold in the U.S. as a dietary supplement, many CBD products are available. These include oils and capsules sold as supplements and CBC waters sold as foods. In February 2016, the U.S. FDA issued warning letters to eight companies selling products containing cannabidiol. The FDA also published the amounts of CBD, THC and other cannabis compounds it found in these products and those tested in 2015 (click here and select the year to view). Many products did not contain the levels of CBD they claimed. The FDA cautions that "Consumers should beware purchasing and using any such products." Most products contained very small concentrations of CBD — similar to what is normally found in hemp oil (about 0.0025% CBD) while others contained very large concentrations (25% to 35% CBD) yielding doses similar to those used in clinical trials (typically 200 mg or more per day).
The reason why hemp oils would not be expected to contain much CBD is that hemp oil is typically made from hemp seeds (i.e., hempseed oil), which contain little CBD. CBD is not found within in the seed (although some may contaminate the surface); it is principally found in the flowers and, to a lesser extent, the upper leaves of the hemp plant. A "CBD oil" product is typically an oil, such as from hemp seed or other sources, to which a CBD extract (from hemp flowers) has been added (Mead, Epilepsy & Behavior 2017). [NOTE:In February 2018, ConsumerLab.com published its Review of CBD and Hemp Oils and Pills, providing tests, comparisons, and reviews of popular CBD-containing supplements and products for people and pets, and updated information about CBD. CL also tested hempseed oils as part of its review of seed oil supplements as sources of omega-3 and omega-6 fatty acids.]
At least one seller of CBD supplements to the public, PlusCBD LTD, appears to claim that is not illegal to sell these products if they are derived from "industrial" or "agricultural" hemp. Industrial hemp is typically a larger plant with more stalk and less leaves and flowers than that used to produce marijuana or CBD for medical use. It is grown for its fiber (for textiles) and seeds (as food and oil), which would be very low in THC (less than 0.3%) and CBD. It is true that the U.S. Drug Enforcement Agency (DEA) has statedthat CBD in trace amounts from cannabis stalk or seeds is not a controlled substance, in contrast to CBD derived from cannabis flower which is a controlled substance -- despite the compound being the same. However, this does not seem to override the FDA's position that CBD cannot be sold as dietary supplement. It would also seem difficult to obtain large quantities of CBD from industrial hemp or cannabis stalk. To help CL members understand how much CBD is actually in oils, capsules, and waters made from hemp, ConsumerLab.com will be testing these products for CBD.
Many states now have medical marijuana laws that permit products with high CBD content to be sold by approved dispensaries and used by residents for medical purposes recommended by a healthcare provider. In addition, several states without medical marijuana laws allow products that are high in CBD (e.g., at least 5%, 10%, or 15% CBD) and low in THC (typically less than 0.3%) to be used for specific medical purposes (typically intractable epilepsy) as approved or recommended by a healthcare professional (See list of states on ProCon.org). However, these state laws do not make the general sale of such products legal, and some specifically require that the products be purchased out-of-state.
Safety concerns:
CBD can cause side effects and interact with certain medications and conditions, although these effects have typically been reported only with very high daily intake, i.e., hundreds of milligrams daily.
High daily doses of CBD (20 mg per kg of body weight, i.e., hundreds of milligrams) may cause decreased appetite, diarrhea, vomiting, fatigue, fever, somnolence, and abnormal results on liver-function tests (Devinsky, New Eng J Med 2017; Thiele, Lancet 2018).
CBD should be used with caution with sedative and sleep-inducing medications, as it may enhance their effects.
CBD can increase blood serum levels of antiepleptic drugs (Gaston, Epilepsia 2017). CBD may increase the blood-thinning effects of warfarin (Coumadin, Jantoven) likely because CBD competes for the same liver enzymes that break down warfarin and other drugs. This was observed in a man with post-stroke epilepsy taking warfarin: His INR (a measure of how long it takes blood to clot) began increasing several weeks after starting CBD (Epidiolex, Greenwich Biosciences, Inc.) for his seizures. His CBD dosing started with several hundred milligrams daily and increased to over 1,000 mg, at which point his warfarin dose had been reduced by approximately 30% (Grayson, Epilepsy Behav Case Rep 2017).
CBD Oil and Supplements with CL founder, Dr. Tod Cooperman
ConsumerLab.com Answers
Question: Are there any supplements I should avoid when taking acetaminophen?
Answer: Acetaminophen (Tylenol, paracetamol) is the most common drug ingredient in the U.S. and is found in more than 600 combination formulas, including Alka-Seltzer Plus Cold formula and the drug Percocet. Although few supplement interactions with acetaminophen have been reported in people, research suggests certain vitamins and herbs may affect how acetaminophen is metabolized in the body — increasing its potential for adverse effects or decreasing its effectiveness. In addition, if you are taking high doses of acetaminophen (which can cause liver damage), it may be best to avoid supplements with the potential to damage the liver. Certain foods can also interact with acetaminophen. There has been some concern over the risk of bleeding when using herbal supplements along with acetaminophen, although recent evidence argues against this.
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Product Review:CBD & Hemp Supplements
Initial Posting: 2/10/18 Last Update: 6/19/18
Choosing the Best CBD & Hemp Oil Supplements
Learn How Much CBD Is Really in CBD & Hemp Oils
We test, evaluate, and compare CBD oils and hemp extracts so you can stay healthy and safe!
CBD oils and hemp extracts in report
Bluebird Botanicals Hemp Classic 6 x Concentrated
CW [Charlotte's Web] Paws
Plus +CBD Oil
Canna-Pet Advanced
Elixinol Natural Drops Hemp Oil + Coconut Extract
PrimeMyBody Nano-Enhanced Hemp Oil
CW [Charlotte's Web] Everyday Plus - Infused Oil Mint Chocolate
Endoca Raw Hemp Oil
SOL CBD Pure Hemp Extract
Make sure the CBD you use passed our tests and is right for you!
Isn't your health worth it?
CBD (cannabidiol) has become popular despite the fact that the FDA has stated it cannot legally be sold as a supplement. There is preliminary evidence that it can help reduce seizures, and may help for anxiety and insomnia. It can be hard to pick the best CBD oil because product labels often don't list what they contain and, even then they do, many have been shown to be wrong. To help, we purchased and tested a variety of CBD oils and hemp extracts for people and pets.
Our tests of CBD products revealed that actual doses ranged from just 2.2 mg to 22.3 mg, and that you can't rely on listed amounts of "cannabinoids" to tell you how much CBD is in a product. We also found that the cost to obtain an equivalent amount of CBD (10 mg) ranged over 5-fold from 80 cents to as much as $4.54. In addition, we checked for contaminants (arsenic, lead, and cadmium) in all products. Products that were the best quality and best value were chosen as our Top Picks.
You must be a ConsumerLab.com member to get the full test results along with ConsumerLab.com's Top Picks and ConsumerTips on how to choose and use CBD. You'll get results for nine popular supplements selected by ConsumerLab.com based on reader requests.
You'll get all of the following information about CBD liquids and pills in this comprehensive report:
Which CBD supplements passed or failed testing
Which CBD supplements offer the best quality and value and are CL's Top Picks
What CBD can and cannot do for your health
The important difference between hemp oil and hemp extract
The dose of CBD for specific uses and how the amounts in products compare to those shown to work in clinical trials
What to look for on product labels
Cautions about the safety and potential side effects of CBD
![CW [Charlotte's Web] Everyday Plus - Infused Oil Mint Chocolate](https://cdn.consumerlab.com/images/products/6046_small_CW-CBDOil-Small-2017.jpg)
![CW [Charlotte's Web] Paws](https://cdn.consumerlab.com/images/products/6053_small_CW-Paws-CBDOil-Small-2017.jpg)
