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CBD Oil Side Effects (Are There Any?)

Woman with head in hand considering if there are cbd side effects

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The benefits of CBD are well documented. We did an entire piece on the medicinal qualities of hemp with the clinical trials to back the claims. Still… can too much of a good thing be bad for you? Too much vitamin C, for example, is known to cause upset stomach and skin flushing. Can CBD – for all of its benefits – cause adverse reactions? We’ll explore some of the potential CBD oil extract side effects and whether users should be concerned or exercise precautionary measures.

CBD Oil Is Generally Safe

Before discussing some of the side effects of using CBD, we want to emphasize that CBD, by and large, is mostly safe. A review of clinical data1 found CBD to have a “favorable safety profile.”

The data reviewed patients who consumed CBD for treating epilepsy and other psychotic disorders. While some subjects did experience side effects, they were mild in comparison to traditional pharmaceutical drugs for treating said medical conditions.

In another study2, patients given doses up to 600 mg of CBD experienced no adverse effects. We should note, though, that doses were administered orally, which has a lower bioavailability compared to vaping or other delivery methods.So, with that in mind, we won’t assume vaping 600 mg of CBD is just as safe.

Side Effects of CBD Oil

CBD oil is not 100% side-effect-free. Some people have more sensitive CB receptors and may respond with unpleasant symptoms. In most cases, the adverse reaction dissipates once the body adjusts.

The aforementioned review of clinical data did find that patients experienced mild symptoms associated with CBD use. This includes:

  • Dry mouth
  • Diarrhea
  • Nausea
  • Vomiting
  • Changes in Appetite (usually an increase)

CBD Interactions with Drugs

are there drug interaction and cbd oil side effects - assorted pills on wooden background
Assorted prescription pills

Does mixing CBD with pharmaceuticals result in unwanted side effects? If you’re on medication, inform your doctor if you’re going to begin CBD supplementation.

CBD use can interfere with your body’s ability to metabolize medicine. This may slow down the breakdown of the drug, causing it to remain in your system longer than necessary. Studies3 show, for example, that CBD use may actually increase the effectiveness of blood thinners. While this may sound like a good thing, the amplified effects may cause complications if you don’t adjust your dose accordingly.

Why does this occur? When taken orally, CBD is metabolized by a liver enzyme known as P450-complex. The same enzyme also metabolizes most pharmaceutical drugs. If the enzyme is busy metabolizing CBD, then it has to delay the metabolization of the medication.

CBD may interfere with any medication that is processed by the liver. There are too many to list, but some examples include:

  • Benzodiazepines
  • Anabolic steroids
  • Fentanyl
  • Antihistamines
  • Macrolide antibiotics
  • Calcium channel blockers

Any CBD oil side effects you experience may not necessarily be from the CBD itself but from the increased potency of the medication due to the delayed metabolization.

CBD Side Effects from Vaping

Vaping CBD may carry its own set of side effects independent of what you might experience from oral CBD. The side effects here stem from the additional additives and not necessarily from the CBD. CBD vape oils and e-liquids commonly contain propylene glycol (PG) as a thinning agent.

The heating coil of lower-quality vape pens produces excess heat, which may convert the PG into tiny polymers that could cause lung irritation.

A study published in the International Journal of Environmental Research and Public Health found that airborne PG can induce asthma and exacerbate allergy conditions. Side effects include watery eyes, wheezing, coughing, and skin irritation.

Heating PG at an extreme temperature converts it to a cancer-causing compound known as carbonyl. The Universal Plant never recommends any CBD vape products that have PG in it. If you do decide to purchase product with PG in it, to avoid respiratory implications, always stick to high-quality e-cigarettes from reputable suppliers. Properly made heating coils do not burn at the temperature needed to convert PG into carbonyl.

What About Side Effects of Terpenes?

If you’re not familiar with terpenes, this refers to a class of oily substances secreted by the cannabis plant. Many plant species actually produce terpenes, but in recent years the term has largely become associated with the cannabis industry.

CBD makers denature the terpenes, turning them into various terpenoids, each with their own distinct flavor. Some terpenoids also interact with the cannabinoids, which can amplify or hinder their effects. Breeders are constantly at work to try to produce terpenoids with desirable flavoring and bioavailability-assisting traits.

Since some terpenes enhance the CBD’s potency, they may also enhance the side effects. The same goes for the side effects associated with the psychoactive compound THC. Industry insiders have referred to this as the “entourage effect.”

As far as the terpenes themselves causing side effects, there aren’t any studies at this point suggesting they cause adverse reactions.

Side Effects from Other Ingredients

You also need to be mindful other additional ingredients. For CBD oil, that includes the carrier oil. For vape juices, this also includes thinners.

Carriers almost always include some sort of MCT oil, such as coconut or palm kernel oil. For the most part, these oils are healthy and have minimal side effects. Adverse reactions are minimal and usually only experienced briefly by first-time users. Minor side effects include: nausea, vomiting, diarrhea, and upset stomach. These sensations are also more likely to occur if you consume the oil on an empty stomach.

For vape juices, additional ingredients include thinners, either in the form of vegetable glycerin or propylene glycol. Let’s examine these two separately.

Vegetable glycerin (VG)

Side effects appear to be minor and usually include a mild headache, nausea, and vomiting.

Propylene Glycol (PG)

We discussed PG earlier and how it may convert into dangerous cancer-causing agents. In addition, a 2014 report4 found that vapor-based PG may cause dry cough and mouth and throat irritation. Some people also report skin irritation when their skin is exposed to PG in vapor or liquid form.

CBD Side Effects ≠ THC Side Effects

Okay, now let’s talk about THC, which has some more noteworthy side effects. As the psychoactive compound, this is the cannabinoid that produces the high and trippy sensation. What are some of the side effects of THC when taken above the 0.3% legal limit?

One of the most widely reported reactions is anxiety. This is due to THC’s biphasic effect. This means it produces a sensation in a low dose and the opposite sensation in higher concentrations. Whereas a small dose may calm the nerves, a higher dose induces the jitters, mood swings, and mild paranoia.

Some of the other side effects include:

  • Dry mouth – this is because there are CB receptors inside the mouth
  • Dry eyes – THC dilates blood vessels in the eyes, leading to dryness and redness
  • Lethargy – some people actually find this feeling helpful as it helps them relax. However, during the day, it can impede day-to-day activities. High THC content is found in the cannabis strain indica, which is known for its sedative effects.

Some lesser-reported side effects include:

  • Headaches
  • Vertigo
  • Difficulty breathing
  • Short-term memory loss
  • Increased heart rate

Some of these side effects, such as dry mouth, is also associated with CBD. However, any overlapping effects appear to be far more pronounced and frequent among THC users.

According to studies, prolonged THC use may also increase risk of some psychiatric disorders, such as schizophrenia.

CBD Oil Side Effects from Full-Spectrum Products

Of course, CBD and THC are only two of the estimated 100+ cannabinoids. What if you’re using a full-spectrum product? Do any of the additional cannabinoids cause side effects of their own?

Some of the other cannabinoids common in a full-spectrum oil include cannabinol (CBN), cannabigerol (CBG), and tetrahydrocannabivarin (THCV). Studies on these cannabinoids are limited. Many of the benefits also overlap with CBD. We can deduce, therefore, that any potential side effects include much of the mild reactions associated with CBD use.

The only standalone side effect we are aware of is an anorectic effect associated with THCV. This means it may reduce appetite. In most cases, this is a good thing as it may be a beneficial weight loss aid. However, some people also take cannabis for pain relief as part of their cancer treatment. Chemotherapy often causes appetite loss. With that in mind, any substance that causes further loss of appetite may be counterproductive. CBD, by contrast, is known to stimulate appetite, hence why cannabidiol is often said to give you the “munchies.” It’s another reason CBD is useful for cancer patients.

Where to Buy CBD Oil

To minimize side effects of CBD oil, always buy from a certified and reputable supplier. Buying a homemade oil from a friend of a friend is probably not the safest bet. You can’t be certain of the carrier oil or thinner used, or the presence of additional ingredients that may cause unwanted reactions.

Reputable suppliers always list the ingredients, which usually consist of no more than the cannabinoid extract, carrier oil, terpenes, and thinner if it’s a vape liquid.

Visit our Where to Buy section for a list of sellers we vetted and verified.

Final Thoughts on CBD Oil Side Effects

We don’t deny that some people will experience side effects. However, we wager that 95% of users won’t have such problems. For those that do experience unpleasant sensations, the effects are mild and temporary. The point we are trying to get across is that CBD is safe. You have nothing to worry about as long as you buy from a reputable supplier and stick to recommended dosages.

Medical References

Iffland K, Grotenhermen F. An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies. Cannabis Cannabinoid Res. 2017;2(1):139-154. [PMC]
Welty T, Luebke A, Gidal B. Cannabidiol: Promise and Pitfalls. Epilepsy Curr. 2014;14(5):250-252. [PMC]
Grayson L, Vines B, Nichol K, Szaflarski J, for the. An interaction between warfarin and cannabidiol, a case report. Epilepsy Behav Case Rep. 2017;9:10-11. [PMC]
Callahan-Lyon P. Electronic cigarettes: human health effects. Tob Control. 2014;23(Suppl 2):ii36-ii40. [PMC]
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Christopher Walker

Christopher Walker has a degree in Neuroscience from Duke University, and is the research writer for The Universal Plant. He has dedicated his life to helping men and women around the world educate themselves and take action to improve their health with natural plant-based and nutrient therapies. Follow him on Instagram @_christopherwalker

2 thoughts on “CBD Oil Side Effects (Are There Any?)”

    1. Hey Sean! Thanks for the comment. Indica is indeed the type of cannabis that’s more sedative. If you’re referring the the fact that there technically is no indica or sativa within the cannabis family genealogy, you’re correct. Technically, cannabis Indica and cannabis Sativa are two completely different types of plant. We use these terms now to delineate between strains of cannabis that have a body-high (indica), and strains that’s more of a head high (sativa).

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