CBD is generally considered well-tolerated, but it can produce side effects. The higher bioavailability of water-soluble CBD means that effects, both intended and unintended, can be more pronounced at equivalent doses. This article covers what is documented about CBD side effects, how to recognize them, and what to do.
Common CBD side effects
The most frequently reported side effects of CBD use include:
Drowsiness or sleepiness
The most common side effect. CBD has a calming effect that can lead to drowsiness, especially at higher doses. This is generally welcomed for evening or bedtime use but problematic during daytime activities. Affects roughly 10-30% of users at typical doses.
Dry mouth
CBD affects salivary glands. The dry-mouth feeling is similar to that experienced with other cannabis products and most antihistamines. Stay hydrated; the effect typically subsides between doses.
Decreased appetite
While THC famously increases appetite ("the munchies"), CBD generally decreases or has neutral effects on appetite. This can be unwelcome if you're trying to maintain weight; it can be beneficial if appetite reduction is desired.
Diarrhea
Higher doses of CBD can cause loose stools or diarrhea. This is dose-dependent and typically resolves with lower doses or discontinuation. More common with concentrated CBD products.
Changes in mood
Some users report changes in mood, both positive (calmer, more relaxed) and occasionally negative (subdued, less motivated). Effects vary significantly between individuals.
Fatigue
Beyond drowsiness, some users experience generalized fatigue, particularly during initial use or with higher doses.
Less common side effects
Nausea and vomiting
Some users experience nausea, especially when starting CBD or at higher doses. Often resolves with dose reduction or discontinuation.
Weight changes
Both weight loss and gain have been reported. The appetite-suppression effect can lead to weight loss; the dietary changes from extended use can affect weight in various ways.
Headaches
Headaches are uncommon but documented. May resolve with dose adjustment or different formulation.
Lightheadedness or dizziness
Some users report mild dizziness, particularly at higher doses. Effects on blood pressure may contribute.
Less well-characterized effects
Liver enzyme changes
Higher chronic CBD use has been associated with liver enzyme elevations in some users. This is a known feature of CBD pharmacology. Routine monitoring is appropriate for sustained high-dose users.
Effect on driving
CBD alone does not impair driving in the way THC does. However, individual side effects (drowsiness, dizziness) could affect driving ability. Use caution before driving when starting CBD.
Long-term effects
The long-term safety profile of regular CBD use is still being studied. Available research suggests good long-term safety, but ongoing research continues to characterize effects.
Special considerations for water-soluble CBD
Because water-soluble CBD has higher bioavailability:
- Side effects may be more pronounced at the same dose vs oil-based CBD
- Lower doses are often appropriate when starting
- Effects may begin sooner (within 15-30 minutes)
- Tolerance may develop differently
Users transitioning from oil-based to water-soluble CBD should consider reducing the dose by 30-50% initially.
Side effects by dose level
Lower doses (5-25 mg)
- Minimal side effects in most users
- Mild drowsiness possible
- Dry mouth common
- Most users tolerate these doses well
Moderate doses (25-100 mg)
- More pronounced effects in users who experience them
- Drowsiness more common
- Appetite changes more noticeable
- Possible mood changes
Higher doses (100+ mg)
- Side effects more frequent and pronounced
- Liver enzyme changes possible with sustained use
- Diarrhea more common
- Drowsiness can be significant
Who should not use CBD
Several groups should avoid CBD entirely or use only under medical guidance:
- Pregnant or breastfeeding individuals: Insufficient safety data; potential effects on fetal development
- Children: Outside specific medical conditions (like seizure disorders), CBD use is not recommended for children
- Those with serious liver disease: CBD is metabolized in the liver; impaired function affects processing
- Those with active cancer: Some chemotherapies are processed by the same liver enzymes; potential for adverse interactions
- Heavy alcohol users: Combined effects may be additive
When to seek medical attention
Side effects requiring medical evaluation:
- Severe drowsiness affecting daily function
- Signs of allergic reaction (rash, swelling, breathing problems)
- Significant nausea or vomiting
- Symptoms that persist after discontinuation
- New mood changes or depression
- Significant weight loss or appetite changes
- Yellow eyes or skin (potential liver issue)
For any concerning symptom, contact a healthcare provider or use Telehealth services for evaluation.
Managing side effects
- Lower the dose: Most side effects are dose-dependent
- Different format: Some side effects are formulation-specific
- Different timing: Drowsiness can be helpful at bedtime, problematic during day
- Stay hydrated: Especially relevant for dry mouth and other minor effects
- Take a break: If side effects accumulate, a temporary discontinuation can help
- Discuss with a pharmacist: Particularly if you're taking other medications
Documenting your experience
Track side effects to identify patterns:
- Dose and timing of CBD
- Format (oil, water-soluble, edible, etc.)
- Symptoms experienced
- Time of onset and duration
- Other factors (food, exercise, stress)
This information helps you and any consulting professional identify what's working and what might need adjustment.