Some people believe CBD oil is safe and well-tolerated. Read about the side effects you can expect and what to be aware of. About 1 in 7 American adults use CBD, according to a 2019 poll. With CBD’s popularity, the question is — are there CBD oil side effects we should be aware of?
7 CBD Oil Side Effects You Should Watch Out For
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CBD oil is believed to be generally safe and well-tolerated, but it is not free of side effects. Read on to learn which adverse effects you should watch out for when using CBD oil, how the delivery form influences them, and what you can do to reduce your risk.
CBD Oil Side Effects
First, it is important to remember that CBD oil is considered experimental and investigational and far more clinical studies are needed before we can make any firm conclusions about its supposed benefits .
Similarly, it’s an insufficiently investigated supplement with a relatively unknown safety profile. The list of side effects listed in this article is, therefore, not a definite one.
So, make sure to speak with your doctor before starting on a CBD oil regimen.
With the recent legalization of CBD oil in many states worldwide, its popularity is booming and people are taking it for not only its FDA-approved use for seizures, but also conditions such as :
An advantage of CBD oil is that it’s considered generally safer and causes fewer adverse effects than the drugs typically used for these conditions. Chronic doses of up to 1500 mg/day were tolerated well in multiple studies [3+, 4].
Unlike THC, CBD doesn’t cause behavioral and psychological side effects. What’s more, it may even reduce some of them such as anxiety, psychosis, and memory loss [5, 6, 7, 8].
CBD oil is believed to cause fewer side effects than THC and most prescription drugs, even at high doses.
Nevertheless, there are some potential side effects of CBD oil that you should watch out for. Below is a detailed overview of the most common ones.
1) Dry Mouth
Whether you use them for recreational or medicinal purposes, cannabis products will often make your mouth feel as if it were stuffed with cotton balls. Almost 12% of 1500 people responding to a survey about CBD use experienced dry mouth, making it the most common adverse effect .
Stimulation of the CB1 and CB2 receptors in the salivary glands reduces saliva secretion, which makes the mouth feel dry. The well-known cannabis compound THC activates these receptors directly. In turn, CBD raises the levels of an activator naturally produced in the body – the cannabinoid anandamide [9, 10, 11, 12].
2) Digestive Issues
Both CBD oil supplements and the FDA-approved CBD medicine Epidiolex have been reported to cause digestive issues such as [2, 4]:
- Nausea and vomiting
- Increased or reduced appetite
- Weight loss or gain
Because preliminary research suggests that CBD improves rather than causes nausea and diarrhea, these effects most likely result from the irritating effects of other ingredients (e.g., carrier oils) on the bowels [13, 14, 15].
Alternatively, the loose regulation of supplements may allow for excessive CBD levels in products or harmful contaminants such as pesticides, heavy metals, and solvents [16+, 17].
In turn, the endocannabinoid system has a role in promoting appetite. The mixed effects of CBD on appetite and weight seen in different studies may be due to its dual effect: it blocks the CB1 and CB2 receptors but boosts the levels of their activator anandamide [18, 19, 11].
If you experience digestive issues from using CBD oil, tell your doctor. He or she may recommend reducing the dose or shifting to another brand.
Contaminants and additives are likely responsible for the digestive side effects of low-quality CBD oil: nausea, vomiting, diarrhea, and appetite and weight changes.
3) Drowsiness and Fatigue
People taking CBD oil often report feeling sleepy and tired. Indeed, this side effect was observed in early clinical trials and one of the most common uses of CBD oil is to improve sleep disorders [20+].
If the symptoms are very severe, you shouldn’t drive or operate heavy machinery.
The effect of CBD on sleep seems to be biphasic: high doses may increase sleeping time, lower amounts may promote wakefulness. Additionally, levels of endocannabinoid receptors depend on the circadian rhythm. This may explain why CBD tends to cause drowsiness later in the day but has the opposite effect in the morning [21, 22, 23].
CBD oil may make you feel sleepy, especially if you take high doses at night. Low morning doses, on the contrary, seem to increase wakefulness.
High doses of CBD lowered blood pressure in a small trial on 9 people. In turn, THC seems to have a more complex effect: it slightly raises blood pressure in people lying down but increases the risk of sudden blood pressure drops when standing up [24, 25+].
As a result, a common adverse effect of CBD – both alone and with equal amounts of THC (nabiximols) – is feeling dizzy and light-headed [26, 27, 28].
If your blood pressure drops too much, you may faint. The risk is especially high in people diagnosed with low blood pressure or on blood pressure medications – such as diuretics, ACE inhibitors, and beta-blockers. These people should be especially cautious with CBD oil and never try it out without discussing it with their doctor.
CBD oil, alone or with THC, may reduce blood pressure. This can make you feel dizzy and light-headed, especially if you are prone to blood pressure drops.
5) Possible Liver Damage
Several trials testing CBD for seizures found possible liver damage (high transaminases ALT and AST) in 9-25% of the people. The risk increased with the dose and was highest in people also taking the anti-seizure drug valproate, which is known to cause liver injuries [29+, 30, 31, 32, 33, 34].
Similarly, CBD caused signs of liver toxicity (high transaminases, alkaline phosphatase, and bilirubin) in mice and dogs. However, the doses were generally higher than those used in human trials [35, 36, 37].
Make sure to talk to your doctor, especially if you are taking valproate, and never exceed the recommended CBD oil dose to reduce your risk of liver damage.
CBD oil may cause liver damage at very high doses and in people prescribed the anti-seizure drug valproate.
CBD is often used to curb anxiety, although research suggests it has “inverted U-shaped” effects: moderate doses, but not low or high amounts, may be effective for a range of anxiety disorders and stressful situations [38, 39].
In contrast, very high doses may even trigger anxiety and irritability. This was the case in 7-9% of the children in 2 clinical trials using CBD for seizures and autism [40, 41].
The effect probably involves the TRPV1 receptor, the activation of which increases the brain’s response to stressful situations .
CBD boosts the naturally-produced cannabinoid anandamide. While moderate anandamide levels activate CB1 receptors and curb anxiety, high amounts may worsen it by binding to TRPV1. CBD also activates this receptor directly, further contributing to the potential anxiety-triggering effects [43, 44, 11, 45].
7) Immune Suppression
CBD may reduce the immune response. It prevents T cells from dividing, migrating to inflammation sites, and producing pro-inflammatory cytokines. This may be beneficial in people with autoimmune conditions such as rheumatoid arthritis or multiple sclerosis [46, 47, 48, 49, 50, 51, 52].
The downside of blocking the immune response is that it may make people with weakened immune systems more prone to infections. Thus, people on immunosuppressants or with conditions such as HIV, diabetes, and Down syndrome might want to avoid it .
CBD oil seems to reduce the immune response, which may make people with a weak immune system more prone to infections.
CBD didn’t damage the kidneys in clinical trials. In fact, researchers believed it protected against kidney injury and inflammation in numerous animal studies [54, 55, 56, 57, 58]. Remember that larger and better designed clinical trials are needed before these findings are conclusive.
Though more clinical trials are needed, the current evidence suggests CBD oil will not harm your kidneys at normal doses.
On the other hand, people with kidney disease should probably avoid THC-containing medical marijuana without consulting a doctor.
According to a recent review, THC may worsen kidney health and increase urination by activating CB1 receptors. Remember that, unlike THC, CBD blocks these receptors. However, CBD may indirectly activate them by increasing anandamide levels in the body [59+].
Lastly, avoid synthetic cannabinoids at all costs (products like “spice” and “K2” sold in smoke shops). These chemicals caused sudden and severe kidney injury in several cases [59+].
Unlike THC and synthetic cannabinoids, CBD oil probably does not cause side effects on the kidneys; some researchers believe it might even be protective.
Are You at Risk of CBD Oil Side Effects?
CBD altered the levels of two drug transporters in placental cells. This suggests that taking CBD oil during pregnancy may increase the exposure of the fetus to any drugs that the mother takes. Pregnant women should avoid CBD oil in any case, since safety data are lacking .
Taking THC-containing CBD oil during pregnancy and breastfeeding is particularly dangerous, since THC may reduce growth and cause brain developmental anomalies in babies [61+].
Because there are no studies testing its safety in children below 2 years old, it’s better to avoid giving them CBD oil unless prescribed by a doctor.
CBD is thought to be safe in older children, but they may be more sensitive to THC and toxic contaminants such as heavy metals and pesticides than adults. Be sure to use high-quality, THC-free CBD in children and consult the doctor first.
Pregnant women and children under 2 years old should avoid CBD oil due to the lack of safety data; THC during pregnancy is known to be dangerous.
Most drugs are broken down by liver enzymes. Among them, cytochrome (CYP) P450 plays a key role. A single CBD dose blocks several CYP enzymes, such as:
By doing so, it may slow the breakdown of several drugs and enhance their effects [62, 63, 64, 65, 66].
Indeed, CBD reduced the breakdown of the sedative hexobarbital, the anti-seizure drug clobazam, and the blood thinner warfarin in humans. It had the same effect on the immunosuppressant cyclosporin and the cannabis compound THC in cells [67, 68, 69, 70].
On the other hand, repeated CBD doses can increase the levels of some enzymes of this group and reduce the effects of the drugs they break down [71, 72, 73, 74].
Plus, CBD itself is broken down by CYP enzymes, especially by CYP34A and CYP2C19. Drugs that block these enzymes (such as ketoconazole and ritonavir) will enhance its effects, while those that activate them (such as phenobarbital and rifampicin) will have the opposite effect [75, 4].
If you are on prescription medication and plan to use CBD oil, ask your doctor about potential interactions and dose readjustment. Additionally, avoid combining CBD oil with grapefruit or other supplements that block the same liver enzymes (such as St John’s wort or watercress).
CBD oil can block or activate liver enzymes that metabolize drugs. This may increase the side effects of both CBD oil and the medication you’re taking.
How Does the Delivery Form Influence CBD Oil Side Effects?
While rapid-release forms (mouth sprays and oil tinctures) deliver CBD directly into your bloodstream, slow-release forms (capsules, edibles, and teas) have to pass your digestive system first. This means their ingredients may irritate your bowels and give you nausea and diarrhea [76+, 77].
However, rapid-release forms will release CBD faster, so you may experience both wanted and unwanted effects sooner [76+, 77].
And since tinctures and sprays are directly applied in the mouth, they will quickly reach the salivary glands and cause dry mouth. Mouth sprays may also cause a stinging sensation and even burns, especially if they contain alcohol [9, 78].
Capsules and edibles are more likely to cause digestive side effects, while mouth sprays and tinctures more frequently cause dry mouth.
Vapes bypass the digestive system without irritating your bowels, but they may trigger the other adverse effects faster [76+, 77].
Vaping is considered safer than smoking cigarettes or joints because the oil is heated at lower temperatures that produce fewer toxic byproducts [76+ 79].
However, the additives used as flavorings and thinning agents in vaping oils may still pose some hazards. Although they are normally food-grade, they may release harmful compounds (including the cancer-causing formaldehyde) when vaporized. Their heavy use may lead to [80, 79, 81+]:
- Dry throat
- Lung injury
- Fat particles entering the lungs (lipoid pneumonia – rare)
For instance, one man developed severe lung damage from vaping CBD oil [82+].
Creams & Gels
Creams and gels act locally on the application site and don’t release CBD into the gut or bloodstream. This means they will not cause most of the adverse effects previously described [76+].
However, they may cause allergic reactions with itching, redness, and rashes on the skin. It’s important to note that the reactions can be caused by either CBD or other ingredients in the formulation [83+, 84+].
How to Reduce Your Risk of Side Effects from CBD Oil
1) Drink More Water
The best way to reduce dry mouth when using CBD oil is to drink plenty of water and other hydrating liquids before, during, and after consumption.
2) Find Additive-Free Products
You can reduce the risk of digestive issues by choosing forms that bypass the gut and directly release CBD into your bloodstream such as vapes, mouth sprays, and oil tinctures. High-quality oils without additives may also irritate your bowels less.
3) Take it Before Sleep
If you feel drowsy or light-headed after taking CBD oil, you may need to reduce the dose or take it only before sleep.
4) Increase Wakefulness Naturally
Drinking coffee or tea will help you both stay awake and raise your blood pressure, but it also causes many side effects. Try to get more sunlight first thing in the morning, as it will energize you and help you get better sleep at night. We talk about other natural ways to increase wakefulness in this post.
5) Support Your Liver
Avoid combining CBD with the anti-seizure drug valproate. Additionally, make sure not to exceed the dose and regularly monitor your liver function to reduce your risk of liver damage. Eggs (choline), artichokes, NAC, and probiotics also support liver health. Read more foods and supplements that are good for the liver here.
6) Don’t Take Megadoses
Only very high CBD doses may cause irritability. Make sure not to exceed the dose and try reducing it if you notice this symptom.
7) Monitor Your Immune Response
If you have a weakened immune system, you should consult your doctor before taking CBD oil. You may need to avoid CBD or take a lower dose.
Additionally, you may also want to look into balancing your Th1/Th2 immune response. If you have a slightly weaker immune system and are prone to allergies, you are probably Th2-dominant.
To reduce your risk of CBD oil side effects, avoid products with additives, drink plenty of water, get sunlight during the day, and support your liver and gut health.
Always make sure to speak with your physician before starting on a CBD oil regimen.
CBD oil is thought to be safe and most people seem to tolerate it well.
Low-quality products may contain additives and toxins that can irritate the lungs when vaped and the gut when taken orally. Choose high-quality products to reduce your risk.
Additionally, CBD oil can make you feel drowsy and lightheaded. If you feel tired after taking CBD oil, lower your dose or use it only before sleep. Look to also increase your wakefulness naturally by getting more sunlight during the day.
High doses may damage the liver, but likely only in people taking the anti-seizure medication valproate. Monitor your liver enzymes and look into natural ways to protect your liver.
Avoid CBD oil if you have a weak immune system, as it might make you more prone to infection.
If you take prescription drugs, consult your doctor. Many drugs can interact with CBD oil and increase the risk of side effects.
Pregnant women and children should avoid CBD oil until more safety data are available.
Some people have genes that make them more likely to experience inflammation. Check out SelfDecode’s Inflammation DNA Wellness Report for genetic-based diet, lifestyle, and supplement tips that can help reduce inflammation levels. The recommendations are personalized based on YOUR DNA.
About the Author
Carlos spent 9 years in the laboratory investigating mineral transport in plants. He then started working as a freelancer, mainly in science writing, editing, and consulting. Carlos is passionate about learning the mechanisms behind biological processes and communicating science to both academic and non-academic audiences. He strongly believes that scientific literacy is crucial to maintain a healthy lifestyle and avoid falling for scams.
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Side Effects of CBD Oil: Potential Risks & What You Need To Know
We can’t deny that CBD oil offers many therapeutic effects — from the relief of common post-exercise pain to the control of severe symptoms such as seizures and post-traumatic stress disorder.
CBD, as a health supplement, became even more popular when studies show CBD to be non-psychoactive, non-addictive, and generally very safe.
As a 2019 Gallup Poll shows, one in seven American adults uses CBD not only for health maintenance but for symptom relief.
With CBD’s popularity, one can’t help but wonder — are there any CBD oil side effects that we have to be aware of?
Types of CBD Products & Their Common Side Effects
Before we go into the details of the CBD side effects, let’s explore the different types of CBD products and their potential side effects.
1. Sublingual (CBD Oil)
CBD oils and tinctures fall under this category. The drops are placed under the tongue and left there for about a couple of minutes. The CBD is absorbed through tiny capillaries under the tongue — directly into the bloodstream.
Common side effects from this type of application include dry mouth, decreased appetite, and changes in bowel habits.
2. Inhalation (Vapes & Hemp Flower)
CBD products that you inhale include smokable CBD flowers and vape oil.
Because you’d be inhaling smoke or vapor, this type of CBD product often causes lung irritation, especially if the product makes use of risky solvents and additives.
Other side effects also include dry mouth, lightheadedness, and dizziness. Some also report developing headaches.
3. Topical CBD (Creams, Salves, & Balms)
These CBD-infused topical products aren’t known to produce side effects when applied to the skin. If they do, it’s pretty rare and usually affects people allergic to hemp or marijuana.
Some of the side effects of CBD topicals include skin rash, hives, and itching.
What are the Common Side Effects of Cannabidiol?
As a whole, cannabidiol (CBD) is generally considered safe. Not only is it well-tolerated by users, but it also doesn’t cause significant adverse changes in one’s physiological parameters (heart rate, blood pressure, temperature, and respiratory rate).
Because of this effect and the fact that there are only a few cannabinoid receptors in the lower brainstem (part of the brain that controls heart and lung function), CBD doesn’t cause an overdose.
This doesn’t mean that CBD is without side effects. Here are the most common side effects to watch out for:
Short-Term Side Effects of CBD
1. Dry Mouth
According to studies, the cannabinoids’ effects on the endocannabinoid system can lead to reduced saliva production, causing cottonmouth (dry mouth).
Drinking plenty of water helps relieve dry mouth.
2. Lower Blood Pressure
The drop in blood pressure is temporary and may be due to CBD’s vasodilation effects on the blood vessels.
When the blood vessels are relaxed and blood flows freely, there’s less pressure against the blood vessel walls, resulting in lower blood pressure.
3. Dizziness & Lightheadedness
The dizziness and lightheadedness may be caused by the drop in blood pressure, but this will go away once it returns to its normal resting pressure.
This effect typically happens to people who take higher doses of CBD.
At very high doses, CBD promotes sleep, while low CBD doses promote wakefulness and alertness.
5. Changes in Bowel Habits
CBD has a relaxing effect on the muscles, so some people develop mild diarrhea after taking CBD since it relaxes the bowels.
However, the changes in bowel habits may also be caused by the other ingredients found in the CBD oil.
Long-Term Side Effects of CBD
There’s still limited research on long-term CBD use, but according to a study, prolonged CBD use has led to increased liver enzymes in mice.
In humans, the long-term side effects of CBD haven’t been completely studied yet, although elevated liver enzymes were also seen in some patients.
Most CBD users report only a few side effects. The side effects they develop are usually mild, well-tolerated, and typically go away once the effects wear off.
Considerations and Precautions Before Taking CBD
It’s possible to develop CBD oil side effects, especially if you’re new to CBD products.
However, you can reduce your risks of developing adverse side effects by understanding these considerations and precautions.
1. Interaction of CBD with Other Drugs
CBD is safe, but we always recommend speaking with your primary care physician first before trying CBD oil. He knows more about your medical history and can help you reach an informed decision.
This is especially important if you’re taking medications. CBD is known to interact with several drugs. it can either amplify or dampen the drug’s potency, which could lead to more unwanted side effects.
2. Pregnant & Lactating Mothers
Cannabinoids are known to cross the placenta and the breastmilk, exposing the fetus or the baby and affecting their growth and development. To be on the safe side, you should avoid CBD if you’re breastfeeding or pregnant.
If you still want to try CBD oil, we recommend speaking with your physician first.
3. Liver Problems
As mentioned earlier, CBD has the potential to increase liver enzymes, so if you have liver problems, it’s best to avoid CBD oil or only use low doses of CBD.
Again, we emphasize the importance of seeing your doctor before taking CBD, especially if you’re diagnosed with liver disease.
4. Allergy to Hemp & Cannabis
Allergic reactions to cannabis and hemp are pretty rare, but they do happen. Coming into contact with the plant, for example, can induce skin allergies, while inhaling its pollen can result in respiratory symptoms.
To reduce the risks of an allergic reaction, you can try dabbing a small amount of oil on your skin and then wait for about half an hour to an hour. If you develop some skin rashes and hives, discontinue the oil immediately and consider visiting a doctor.
How to Avoid CBD Side Effects?
CBD oil is generally well-tolerated by users. Once your body gets used to the addition of CBD, these side effects resolve on their own.
However, these side effects can also be pretty uncomfortable, so if you want to avoid them or at least reduce their intensity, follow these simple tips.
1. Start Low, Go Slow
This term simply means starting at the lowest dose possible and increasing or decreasing the dosage according to your needs.
For example, the instruction is to take one full dropper, then you can start with half a dropper for about three to five days. If you didn’t notice any improvement, increase the dosage.
However, if you developed adverse side effects on half a dropper, then decrease your dosage.
Be consistent and be patient. You’ll soon find a dosage perfect for your health needs.
2. Know Who Should Not Take CBD
If you’re allergic to hemp or cannabis, take medications, have liver problems, are pregnant, or are lactating, then be extra cautious in using CBD oil.
Again, we recommend seeing your doctor before using CBD oil.
3. Look for the Product’s Certificate of Analysis
Trusted CBD brands always have their products tested by certified testing facilities to check for the presence of harmful pathogens, heavy metals, solvent residues, dangerous pesticides, and artificial fertilizers.
Don’t trust brands that can’t show proof of their CBD oil’s safety and quality.
4. Read Reviews
Reviews made by customers can help you choose a good CBD oil. These reviews let you know about the product’s expected effects (and side effects, if any).
5. Avoid Too-Good-to-be-True Claims
Bogus CBD companies will promise you the moon if they think it’ll make you buy their products. Their CBD oil can cure all types of diseases, and their CBD oil is the cheapest on the market.
Producing premium-grade CBD oil doesn’t come cheap. Legit CBD brands invest money to buy state-of-the-art equipment and purchase high-quality, organic raw materials.
If you see CBD brands offering cheap but “quality CBD oil,” avoid them. Not only are they violating FDA rules, but they may also be lying about their products, especially if they can’t produce valid laboratory test results.
Final Thoughts: Side-Effects of CBD
It’s safe to use CBD oil daily. It can ease discomfort and help maintain normal health and wellbeing.
However, like most health supplements, CBD also has its own side effects. It can cause dizziness, lightheadedness, dry mouth, changes in bowel habits, and sleepiness. It can even lower blood pressure.
These side effects are very well-tolerated by users. They also typically go away once your body gets used to CBD.
You can avoid these side effects by following the precautions and considerations mentioned above. You can also reduce the risk by choosing CBD oil made by trusted brands.
Have you tried CBD oil and experienced some side effects? What did you do to get rid of them?
Livvy is a registered nurse (RN) and board-certified nurse midwife (CNM) in the state of New Jersey. After giving birth to her newborn daughter, Livvy stepped down from her full-time position at the Children’s Hospital of New Jersey. This gave her the opportunity to spend more time writing articles on all topics related to pregnancy and prenatal care.