CBD (cannabidiol) is a natural compound extracted from the hemp plant, and it has become popular as a supplement for everything from stress and anxiety to chronic pain and sleep disorders. One of the major advantages of CBD is that it is not psychoactive like THC—you do not get “high” from using it. It is also generally considered safe and well-tolerated. However, like all active substances, CBD can cause side effects, especially at high doses or when taken together with other medications.
The Most Common Side Effects
While many people use CBD without experiencing any issues, a number of reactions have been documented in both clinical studies and user reports:
Tiredness and drowsiness:
CBD has a calming effect, which for some leads to increased drowsiness—especially when taking higher doses or combining it with other relaxing substances. This may be helpful at bedtime but inconvenient during the day.
Dry mouth:
CBD can affect saliva production, resulting in an unpleasant dry mouth. It is not dangerous but can be annoying.
Changes in appetite and weight:
Some users experience increased appetite, while others report reduced hunger. This may affect eating patterns and weight over time.
Low blood pressure:
CBD can temporarily lower blood pressure, especially shortly after ingestion. This can cause dizziness, fatigue, or light-headedness.
Digestive issues:
Especially at higher doses, CBD can cause diarrhea, bloating, or stomach discomfort. This may be due to both the CBD itself and the carrier oil (such as MCT or hemp seed oil).
Rare but More Serious Side Effects
In rare cases, more serious side effects have been reported:
Liver enzymes:
Some studies show increases in liver enzymes in people taking high doses of CBD over extended periods. This is particularly seen with prescription CBD medications such as Epidiolex.
Psychological reactions:
A small number of users have reported restlessness, irritability, or mood swings, particularly at very high doses. This is uncommon but worth noting.
Interaction With Medications
CBD can affect how the body breaks down certain medications. This happens through its influence on liver enzymes in the CYP450 system, which plays a key role in metabolizing many drug types. This means CBD can either increase or decrease the effects of other medications—and in some cases raise the risk of side effects.
Medications to be especially cautious with include:
- Blood thinners (e.g., warfarin)
- Antidepressants and anti-anxiety medications
- Anti-epileptic drugs
- Pain and anti-inflammatory medications
- Blood pressure medications
It is strongly recommended to speak with a doctor or pharmacist if you are taking regular medication and are considering using CBD.
Special Precautions
Pregnancy and breastfeeding:
There is not enough research to determine whether CBD is safe during pregnancy and breastfeeding. It is generally discouraged for these groups.
Liver disease:
People with impaired liver function should use CBD cautiously and may need regular monitoring of liver enzymes.
Age and body weight:
Older individuals and those with low body weight may be more sensitive to CBD and should start with an extra low dose.
Driving and machinery:
If you experience drowsiness or dizziness while using CBD, avoid driving or operating dangerous machinery.
How to Minimize the Risk of Side Effects
- Start with a low dose (e.g., 5–10 mg of CBD per day) and increase slowly.
- Choose a product with clear dosing instructions and verified content (preferably with a lab certificate).
- Take CBD with food to improve absorption and reduce stomach issues.
- Pause use and consult a health professional if you experience discomfort or unusual symptoms.
Summary
For most people, CBD is a safe and well-tolerated supplement, but like all active substances, it carries a risk of side effects—especially at high doses or when combined with medication. The most common side effects include tiredness, dry mouth, changes in appetite, and mild digestive issues. More serious side effects are rare but should be taken seriously, especially for those with health conditions or who take other medications.
By starting low, choosing quality-assured products, and seeking medical guidance when needed, CBD can be used safely and with minimal risk.