Q&As

CBD is cannabidiol, a member of a special group of compounds in the cannabis plant called cannabinoids. Unlike the most well known cannabinoid, tetrahydrocannabinol (THC), CBD does not produce a "high". For many people, using cannabis products that mostly contain CBD rather than THC is an easier way for them to get started with a reduced risk of side effects. CBD was discovered in 19401. Since then, substantial research has been conducted on it, mostly using isolated cell cultures and animals. Many clinical trials with people have been conducted as well.

CBD products containing less than .3% THC became legal in 2018 as a result of the Farm Bill passed that year2. However, the Food and Drug Administration has formally approved only one CBD product, called Epidiolex, for the medical use of treating seizures associated with rare epileptic conditions. All other CBD products in the market are largely unregulated, but many producers conduct voluntary testing to ensure the safety and quality of their products. Such testing includes measuring the level of CBD in the product as well as ensuring the absence of contaminants like pesticides, bacteria, and heavy metals. While more regulation and research is needed, thousands of consumers currently report benefits from using over-the-counter CBD products. Benefits are more likely when lab-tested products are used.

There has been a substantial amount of research conducted on humans and CBD. For example, clinical studies have shown CBD exerts benefits in patients with schizophrenia, social anxiety, Parkinson’s disease, and various types of epilepsy 3. Case studies of individual patients along with animal studies suggest CBD could help many more conditions, including drug abuse problems, post-traumatic stress disorder, depression, and sleep disorders4. The antioxidant, anti-inflammatory, and neuroprotective properties of CBD appear to contribute to its benefits and may lead to CBD’s further use for other diseases that involve inflammation or nerve damage.

It has been reported from several sources that low doses of CBD tend to be energizing and high doses are sedating, although the only way for any individual to know how CBD will affect them is to try. For example, a CBD website run by an experienced cannabis physician states that 1-10mg CBD can be stimulating, while higher amounts above 25mg may be sedating5. This means CBD may help with both low energy and sleep.

While more clinical trials are needed to confirm how much CBD can really do, the existing evidence is promising. Many people have found that CBD has benefited their health conditions when other treatments failed. It is important to remember there are no guarantees of effectiveness for any particular individual, but CBD is a remarkably safe compound that is often worth exploring.

Effects vary across people and not everyone responds the same. However, using CBD products definitely presents less risk than using THC products.

CBD could theoretically help canines with anything it could for humans, because dogs have the same biological system, the endocannabinoid system, that humans do, which is largely responsible for the beneficial effects of ingesting CBD. There is far less clinical research with dogs and CBD than humans and CBD, but some does exist. A 2022 study identified several trials where CBD improved activity levels and reduced pain in dogs with osteoarthritis6. Another trial found that CBD reduced seizures in dogs with epilepsy7. These studies indicate that CBD can work for dogs with at least some conditions, and give more weight to the anecdotal evidence from people who report benefits in their CBD-treated dogs.

Despite the overall safety, it is still best to start with low doses of CBD and increase slowly to make sure there are no side effects. Another reason to use low doses is that dogs have more cannabinoid receptors in their brains than humans 8, so lower doses may be needed to achieve the same effects. The additional receptors may also increase side effects if the doses are too high. Besides arthritis and epilepsy, anecdotal evidence suggests CBD can help with neuropathic pain, anxiety, nausea, and appetite stimulation9.

Clinical evidence suggests that CBD is a remarkably safe compound. A systematic review of clinical trials published in 2020 reported that the only side effect of CBD found in trials outside of childhood epilepsy studies was diarrhea 10. In epilepsy studies, other effects like abnormal liver function, drowsiness, and pneumonia also occurred, but the authors noted these may have been a result of CBD interacting with anti-epileptic medications. Nonetheless, some people have reported side effects after taking CBD. A physician writing for the Mayo Clinic noted that CBD may cause side effects of diarrhea, dry mouth, reduced appetite, and drowsiness11.

The best way to reduce possible side effects of CBD is to start with low doses of 1-2mg and increase by 1-5mg per dose. While starting with a higher dose is probably okay, anyone who wants to be as safe as possible should follow the “start low and go slow” dosing advice.

There is evidence that CBD can interact with some types of medications. CBD is known to inhibit enzymes in the liver which are responsible for processing pharmaceutical drugs12. Therefore, if CBD is taken at the same time as drugs which are processed by these enzymes, it may slow their metabolism and lead to higher drug levels in the body than intended by the drug manufacturers, which may increase side effects of the drugs. The most well-characterized effect concerns combining CBD with anti-epileptic medications like clobazam and sodium valproate, where it is potentially likely to interfere with liver function and increase likelihood of pneumonia10. The minimum doses at which interference may emerge appears to be between 25-40mg13.

Much more research is needed on how CBD interacts with other drugs, as right now, the only serious known risks appear to be combining CBD with anti-epileptic drugs, including benzodiazepines. Risks could exist for other medications, however, so care is needed when combining CBD with other drugs. Thankfully, there are some methods for reducing risk. Spacing out CBD from the doses of any other medications as long as possible will reduce risk of interactions. Taking as little CBD as you need to achieve benefits will also reduce risk, since higher doses of CBD have a greater impact on liver enzymes.

You should also be aware of the common side effects of medications you are taking. If you have not been experiencing listed side effects of a certain prescription, and begin experiencing them after taking CBD, you should stop CBD, reduce the dose, or space it out longer from that medication. For example, CBD may exacerbate the drowsiness, sedation, or nausea of other medications14.

A tool called the Medscape Drug Interaction checker can check for drug interactions15. You can put in “cannabidiol” and any other drugs you are taking and the tool will tell you if they interact. If they do, it is especially important to space out the CBD from that drug by as much time as possible. Eventually, more research will better answer what drugs can be safely combined with CBD. .

There is no evidence that giving CBD to children has any negative effects, although more research is needed. The most research with CBD and children has only taken place in the context of epilepsy trials, so the results are not applicable to children without epilepsy. A 2020 review of studies on the benefits and risks of CBD products for children determined that any potential risks have not been rigorously studied yet16. Given the lack of research, it is probably most prudent to avoid giving children CBD unless they have a clear medical need.

Cannabis is not absorbed well transdermally (through the skin and into the bloodstream) and needs to be combined with other substances to achieve this property17. Cannabis can be used topically to potentially alleviate pain and inflammation, but this effect is limited to where the cannabis is applied18. Cannabis products that are processed in such a way to become transdermal can enter the bloodstream and exert effects on the whole body. Transdermal patches tend to be time-released, so the effects will often last longer than inhalation and act more like orally ingested cannabis.

A study published in 2022 followed patients with sleep disorders for 3 months who combined low doses of melatonin (1.5mg) and CBD (2.5mg)19. Results suggested the patients had reduced anxiety, depression, and pain as a result of treatment. There was no evidence of a harmful effect. However, this is the only study apparently in existence for now, and given its short-term nature, nothing can be said for certain about long-term effects. However, there are many products available that combine CBD and melatonin, so their rising presence suggests continued demand for them.

It is more efficient to consume cannabis after having eaten a fatty meal, as fat helps cannabinoids absorb better. A 2019 trial found that taking CBD 30 minutes after a high-fat meal led to a 14 times higher maximum concentration of CBD in the blood than in a fasted state22. Given the structural similarities between CBD and other cannabinoids, it is reasonable to assume that other cannabinoids in cannabis are also absorbed better after a fatty meal.

Extracting cannabis into a food-grade oil is a process known as infusion, and it allows people to easily ingest the compounds in cannabis without eating the plant directly. There is little scientific evidence showing what oils are best, but olive and MCT (medium-chain triglyceride oil derived from coconut or palm fruit) oils are by far the most popular. Thankfully, there is some evidence which supports the benefits of using these oils. First, a 2013 study compared four different substances for extracting or infusing cannabinoids, including naphtha, ethanol, petroleum ether, and olive oil24. Of these, olive oil pulled out more THC and terpenes than the other substances, indicating it is a good oil to infuse cannabis into.

Next, an informal study in 2016 conducted by a cannabis journalist compared the infusion effectiveness of five different fats, including butter, olive oil, avocado oil, coconut oil, and bacon fat25. Even though the same process was followed for each infusion test, two different labs produced different results, with one showing olive oil was the best and the other showing clarified butter was the best. Coconut oil was the second most efficient oil in one of the tests as well. It is reasonable to expect that MCT oil would act similarly to coconut oil since MCT oil used in cannabis infusions is usually derived from coconuts. Final point - Evidence shows that the most commonly used oils for infusing cannabis, olive and MCT, are effective and their use is justified.

Producing concentrated extracts is different from producing infusions. It involves soaking the cannabis in a solvent like ethanol or running a gas through it like butane or carbon dioxide. The solvent can be evaporated leaving just the concentrated plant materials and no other substance, unlike infusions where the fatty oil remains as well. The 2013 study referenced above showed that ethanol is effective for extracting24, and the cannabis marketplace has demonstrated that butane and carbon dioxide are also effective for pulling out a wide range of cannabinoids and terpenes. For most patients, there is no need to use extracts, as they are designed either for smoking or taking in very high doses of cannabinoids. Infused oils are easier for most patients to use and allow more precise dosing.

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