[1] People use CBD oil for anxiety, pain relief, epilepsy, and other conditions. CBD oil is legal in most U.S. states and many European countries, and it can be purchased online or at speciality stores. Unlike marijuana, CBD oil does not contain THC, which is responsible for the psychoactive effects. In other words, CBD oil does not get you high. 

CBD oil dosage

CBD oil dosage will vary depending on the condition being treated. It is always important to start with a low dose and increase gradually as needed. Healthline[2] recommends beginning with 20-40 mg per day and increasing the dosage if needed. After a week, for instance, you may want to increase the dose by 5 mg and see how that feels. Whether you use CBD gummies, capsules, or tinctures, check the label to see the milligrams of CBD in each serving. If you use CBD oil, the label should say how many milligrams of CBD are in each drop. Don't forget to buy the best CBD oil from recognized brands because not all CBD oils are created equal.

CBD oil side effects

Even though CBD oil is considered "generally safe"[3] by the World Health Organization (WHO) and others, it can still cause some side effects. CBD oil side effects can vary from person to person. Some people may not experience any side effects, while others may experience a variety of side effects. The most common side effects include:

1) Dizziness

Dizziness is one of the most common side effects of CBD oil. It can cause you to feel lightheaded and unsteady. If you experience dizziness, it is best to avoid activities that could put you at risk for injury, such as driving or operating heavy machinery. A 2021 study of Poison Control Centre cases found that dizziness, vertigo, and nausea were the most common CBD oil side effects.

2) Dry mouth

CBD oil can cause you to experience a dry mouth. This is because it reduces saliva production. Saliva is essential for oral hygiene and preventing cavities. A 2006 study[4] by the University of Buenos Aires, Argentina, concluded that CBD oil may cause dry mouth.

"The research team found that anandamide, which is one of the two major endocannabinoids produced by the body, binds with high affinity to these cannabinoid receptors and blocks the secretion of saliva," wrote[5] Nina Julia, a science and math teacher in her popular blog CFAH.org.  

"Both THC and CBD interact with the cannabinoid receptors of the parasympathetic nervous system, so they're likely to affect the receptors of the submandibular glands in a similar fashion," she added. 

3) Reduced Appetite

Unlike THC, which can increase appetite,[6] CBD oil can cause you to have a reduced appetite. This is believed to be due to the way CBD oil interacts with CB1 and CB2 receptors in the body. 

A 2018 study[7] by five academics from the University of Campania "Luigi Vanvitelli" in Italy examined the use of CBD oil to treat obesity. It found that CBD oil may help reduce appetite and promote weight loss by stimulating CB2 receptors and deactivating CB1 receptors, responsible for stimulating appetite.

"Diet intervention and correct lifestyle are surely the best solution, but dietary regiments are negatively affected by a strong cultural influence, especially in certain areas of the world, therefore it is sometimes not an efficient approach," the authors wrote. "The recent findings in the field of browning in humans have pointed out the potential role of this phenomenon in obesity treatment." Browning is the process of turning white adipose tissue, or "bad" fat, into brown adipose tissue, or "good" fat.

Though obesity is a major global health concern, not everybody taking CBD may want to lose weight. For those already at a healthy weight, or those who don't want to lose weight, CBD oil could still cause a reduction in appetite. Users need to know this before using CBD oil if weight loss is not the desired outcome.

4) Fatigue

Another common side effect of CBD oil is fatigue. People have reported[8] feeling tired, lethargic, and drowsy after taking CBD oil. While CBD oil is used to treat sleep disorders, it may not be the best choice for those who want to stay alert. If you experience fatigue after taking CBD oil, it is best to avoid activities that require physical or mental energy.

"The effect of CBD on sleep seems to be biphasic," write Carlos Tello, PhD (Molecular Biology), in a medicaly review article "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." 

5) Diarrhea

Upset stomach, digestive problems, and diarrhoea have been reported[10] in people taking CBD to treat schizophrenia and epilepsy as side effects during clinical trials. It remains unclear why this occurs. Some believe this could be due to other ingredients in CBD oil products or because of interactions between CBD and other medications people are taking.

"While CBD oil can cause diarrhoea as a side effect," wrote Georgia Smith, in a medically reviewed article,[11] "it could be the other ingredients in the CBD oil that are causing your gastrointestinal distress instead. It could also be a simple case of flaws during the manufacturing process." The article recommended avoiding coconut oil and MCT oil since they are the most likely causes of stomach-ache, constipation, and diarrhoea. 

6) Low blood pressure

People with low blood pressure should be cautious when taking CBD oil, as it has been known to lower blood pressure even further. This could lead to dizziness and light-headedness. If you are taking medication for low blood pressure, consult your doctor before using CBD oil. A 2017 study[12] by three scholars from the Oxford and Nottingham universities in the United Kingdom found "a single dose of CBD reduces resting blood pressure and the blood pressure response to stress, particularly cold stress, and especially in the post-test periods."

"This may reflect the anxiolytic and analgesic effects of CBD, as well as any potential direct cardiovascular effects," it added, noting that further research is needed to establish beyond doubt whether there is a causal link between CBD and blood pressure changes.

"CBD also affected cardiac parameters but without affecting cardiac output. Giving the increasing use of CBD as a medicinal product, these hemodynamic changes should be considered for people taking CBD," the researchers wrote.

In brief, CBD oil side effects can vary from person to person. People may experience dizziness, dry mouth, reduced appetite, fatigue, diarrhoea, and low blood pressure. Users should be aware of these effects before using CBD oil and take appropriate precautions. It is also essential to consult with a doctor before taking CBD if you are pregnant, breastfeeding, or taking any other medications. Despite the side effects, CBD oil has been found to have many benefits for a variety of medical conditions. CBD oil is widely considered a safe and effective treatment for anxiety, pain, and other conditions. Do your research before purchasing CBD oil to ensure buying the best CBD oil in the market. For more information on CBD oil side effects, please consult with a healthcare professional.