CBD Oil Side Effects - Can it Cause Headaches?

6 Minute Read

These days we are seeing all the seemingly miraculous benefits of cannabidiol (CBD) pile up. But what about the side effects?

Perhaps you’ve heard anecdotal stories of CBD causing fatigue, diarrhea, and even headaches.

We must keep these stories in mind because for everything we put into our bodies we must first balance all its potential pros and cons. 

In this article, we will set the record straight by thoroughly examining the side effects of CBD,  specifically if it can produce headaches.

A close up of a cannabis leaf.

CBD at a Glance

Despite its use in alternative medicine for 3,000 years, the cannabis plant has been illegal for decades.

CBD was only first discovered and isolated in the 1940s at which time its benefits were unknown.

But with the legalization of medical marijuana in some parts of the country, the cannabis craze was officially ignited.

Following suit, the legality of hemp-derived cannabidiol was passed by way of the Farm Bill of 2018.

Due to its only recent legalization, we are just now developing detailed clinical research surrounding the cannabis plant and its many cannabinoids.

CBD is federally legal if it contains less than 0.3% Tetrahydrocannabinol (THC), the psychoactive compound that is prevalent in the illegal substance marijuana.

Since the hemp plant is lower in THC, CBD is most often derived from this variety.

Cannabidiol combines with terpenes and other cannabinoids including low amounts of THC to create full-spectrum CBD oil products.

These oils have hit the health and wellness market, where they are celebrated for their possible benefits for anxiety, pain, and inflammation relief. 

Potential Side Effects of CBD Oil

The effects of CBD oil are quite mild. The most common side effects that are reported by CBD users are tiredness, diarrhea, and changes in appetite.

These effects may seem minuscule when compared side-by-side with some prescription medications.

Comparable drugs used to treat the same conditions can have much worse and debilitating side effects. That being said, some people should avoid using CBD:

-  People with liver disease should use CBD oil with caution. 
-  Women who are pregnant or breastfeeding should avoid CBD due to the possible risk of babies’ development. 
-  Someone who is planning to drive or use heavy machinery when using full-spectrum CBD, especially when first starting treatment or trying a new brand. 
-  If you have problems with low blood pressure or high blood pressure or are taking blood pressure medications.

    Talk to your doctor if you are thinking about taking CBD oil to treat any medical conditions you may have.

    This will decrease the risk of side effects occurring. So now that we know who shouldn’t be using CBD, let’s determine what side effects we may expect.

    Side effects vary from person to person. Here are the symptoms that clinical research has discovered:

    -  Changes in appetite/weight: CBD can either increase or decrease appetite. This can result in fluctuations in weight. 

      -  Diarrhea: This is a common unfortunate effect of some CBD oils. This is typically not caused by the CBD itself, but because of the carrier oil (coconut, grapeseed, olive, or hemp oil).

      If possible, try not to consume CBD oil on an empty stomach. It may also help to eat some protein with the dose to help reduce how quickly your body absorbs it.

      If this still doesn’t help, try CBD capsules, gummies, or topicals to avoid the oils. 

      -  Dry mouth: This 2006 study showed that CB1 and CB2 receptors are present in salivary glands. The receptors are activated with CBD, after which the saliva production decreases, which causes the mouth to dry. Not considered dangerous, this condition will simply prompt you to drink more water. 

      -  Fatigue: Since CBD may be used as a sleep aid for insomnia-sufferers, it makes sense that high doses can cause fatigue and drowsiness. If this is the case for you, don’t take CBD before driving or operating a vehicle. 

      -  Nausea: For some people, ingesting CBD oil can cause mild nausea. This is in direct conflict with CBD helping relieve nausea in some people, as well as increasing appetite. Nausea should go away quickly. If this occurs for you, decrease your dosage.

      -  Lower blood pressure: Taking CBD in high amounts may cause a small decrease in blood pressure for some people. It happens at the time CBD enters the system, but will not happen to everyone. It may cause a feeling of lightheadedness. 

      -  Dizziness: The feeling of lightheadedness or dizziness is typically associated with a drop in blood pressure. It should pass on its own, or it may help to lay down for a few minutes or snack on something with a cup of tea.

      -  Vomiting: Although CBD can potentially help reduce nausea and vomiting in chemo patients, it is also said to cause vomiting as a side effect. Unfortunately, some people have trouble digesting CBD oil.  

      -  Anxiety: Even though CBD oil may be helpful in the treatment of some anxiety disorders, it has been also found to increase anxiety in some cases. 

      -  Headaches: It is possible that CBD oil can cause headaches. However, the majority of clinical trials and user experiences do not have headaches as a side effect. More evidence is needed on how and why headaches may occur.

        A woman in bed with her head in her arms

        Reasons for Headaches Caused by CBD

        Though headaches can be caused by CBD, they are a relatively rare occurrence, compared to other possible side effects listed above.

        If you do have a headache when taking CBD, first make sure to rule out other possible factors like:

        -  Dehydration
        -  Stress
        -  Lack of sleep
        -  Fatigue
        -  Hunger
        -  Caffeine withdrawal
        -  Sensitivities to food and drinks, including alcohol

        If you do experience a headache caused by CBD, however, it may be from one of the following reasons:

        -  Taking the wrong dosage for you: Side effects often occur due to taking the wrong dose of CBD. This can happen by overestimating the amount you need, or not monitoring how much you are taking.

        For this reason, it is important to always start with a small dose to judge your sensitivity to CBD use. If you start with a low dose, you can gradually work up to the level that works best for you, causing minimal side effects.

        It is important that you get the dosage right, and that you are consistent. This will allow for the best results.

        -  Low-quality CBD: The only FDA-regulated CBD drug on the market today is Epidiolex, a purified CBD extract for two forms of epilepsy. 

        Due to the lack of FDA regulations in this brand-new industry, there are some producers and dealers out there who just want to make a buck.

        As a result, they cut corners when it comes to producing a good quality product. This has created a surge of products on the market filled with harmful chemicals and synthetic substances.

        Products that don't contain organic CBD oil may cause side effects like respiratory problems, allergies, and headaches. Switch to a high-quality CBD oil that is hemp-derived instead.

        - The product contains harmful contaminants: The low-quality CBD products can contain solvents like ethanol and isopropanol, or chemicals such as mercury or lead. 

        Because cannabis is grown and produced all over the world, it can contain different toxins depending on how and where it was grown, and how it was processed.

        Not practicing safety protocols or being careless during all of these processes could result in contaminated or diluted CBD.

        These products could impact your health with things like headaches, respiratory diseases, and sometimes even death. 

        -  Product hasn’t been third-party lab-tested: Having a product that hasn’t been lab-tested by an unbiased third party will increase the likelihood that it contains ingredients harmful to your health. 

        On the other hand, testing that is independent and regulated will produce a report of exactly what it is in the product.

        This will allow you to see the quality and potency of the CBD.
        The tests will also give warnings of the use of any chemicals, bacteria, or pesticides that may or may not be in the product.

        In this way, you can easily select the CBD oil that has been created with all the best practices in mind. 

        -  CBD may not be for you: Everyone’s body is different and the effects of CBD may vary.

        The way your body responds to the dosing could cause a headache if it doesn’t jibe well with your internal chemistry.

        That is why it is always strongly recommended to consult your doctor to determine if CBD is right for you.


        Pay Attention to Drug Interactions

        Another reason to talk to your doctor before taking CBD is to determine whether it can safely interact with any medications you may be taken.

        These interactions may increase the severity of CBD side effects. The reason for these negative interactions may be due to CBD’s inhibition of the enzyme cytochrome P450, or CYP450.

        This is an enzyme some drugs use for metabolization. As a result, CBD can either increase the drug’s toxicity or decrease its effectiveness.

        Some of the medications that negatively interact with CBD may be:

        -  Blood thinners like warfarin
        -  Heart rhythm medication like amiodarone
        -  Thyroid medication like levothyroxine
        -  Seizure medications like clobazam, lamotrigine, and valproate. 
        -  Rifampin-based drugs for tuberculosis
        -  Opioids like fentanyl and alfentanil 
        -  Antiarrhythmic drugs like quinidine 
        -  Migraine medications like Ergomar (ergotamine)
        -  Anticonvulsants like Tegretol (carbamazepine) and Trileptal (oxcarbazepine)
        -  Macrolide antibiotics like clarithromycin and telithromycin
        -  Antifungal drugs like Nizoral (ketoconazole) and Vfend (voriconazole)
        -  Immune-suppressive drugs like Sandimmune (cyclosporine)
        -  Antipsychotic drugs like Orap (pimozide)
        -  Benzodiazepine sedatives like Klonopin (clonazepam) and Halcion (triazolam)
        -  Antidepressants like Remeron (mirtazapine)


        The interactions of these drugs can be mild and may not require any adjustment to your treatment.

        Or, you may be able to switch your medication with an interchangeable drug that will not interact negatively.

        There is also the possibility that you may simply separate the dosing of your medications to different times of day to where they will not interact.

        Talk to your doctor about any drugs you are taking, not just prescription medications, but also over-the-counter, herbal, and recreational. He or she will be able to better ascertain your situation.

        Reduction of Migraines

        Despite the rare occasion that CBD may cause headaches, there is also the possibility that it can have the opposite effect.

        There is evidence emerging that cannabis may help with the pain of headaches and migraines.

        This could likely be due to both CBD and THC’s ability to reduce chronic pain and inflammation.

        CBD has anti-inflammatory effects that may help with migraine headaches. This may be done through its interaction with the endocannabinoid system (ECS). The ECS regulates a lot of important processes in our bodies including:

        -  Mood
        -  Memory
        -  Appetite
        -  Muscle control
        -  Immune function
        -  Inflammation
        -  Pain

        The CBD influences the ECS by interacting with the endocannabinoid receptors. 

        These receptors regulate pain and inflammation, including TRPV1 receptors, CB1 and CB2 receptors.

        THC binds to CB1 receptors that are abundant in the brain and nervous system, reducing the sensation of pain.

        Due to the dual effect of both CBD and THC, this may cause added benefits in the treatment of pain.

        For this reason, we believe a full-spectrum CBD oil may help reduce the symptoms of chronic migraines.

        Though research is still in its early days, there is hope that cannabidiol can become recognized as a safe and effective use for the treatment of these conditions.

        May Cause or Treat Headache Pain

        Headaches can be a debilitating condition that can greatly affect our daily lives. Finding out what is causing your headaches is important for determining how to treat them.

        If you have taken a high dose of CBD oil, or are using a low-quality oil (that has not been third-party tested), these may be possible causes of your headaches.

        Though headaches are a rare side effect of CBD oil, the evidence is showing that it can also produce the opposite effect: relief from headache pain.

        Disclaimer: This content is for informational purposes only. It is not provided to diagnose, treat, cure, or prevent any disease or ailment. It should not be interpreted as instruction or medical advice to displace the advice of your doctor or other medical professionals. We recommend talking to your doctor to prepare a treatment plan for any diseases or ailments.

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