Safety & Risks
Is CBD safe?
TL;DR — What the Evidence Shows
CBD is generally well-tolerated but is not risk-free. Common side effects include tiredness, diarrhea, and changes in appetite. The most serious concern is drug interactions — see our dedicated page.
The most important page on this site
Drug Interactions →
CBD affects liver enzymes that process about 60 out of 100 prescription drugs.
What are the common side effects?
The most rigorous side effect data comes from clinical trials of Epidiolex, the only FDA-approved CBD product. Trial doses (700 to 1,400 mg per day for a 70 kg adult) are far higher than typical over-the-counter CBD products (15 to 100 mg per day). Side effect rates at consumer doses have not been studied in controlled trials.
| Side effect | Placebo | CBD (lower dose) | CBD (higher dose) |
|---|---|---|---|
| Fatigue / drowsiness | About 8 out of 100 | About 23 out of 100 | About 25 out of 100 |
| Diarrhea | About 9 out of 100 | About 9 out of 100 | About 20 out of 100 |
| Decreased appetite | About 5 out of 100 | About 16 out of 100 | About 22 out of 100 |
| Liver enzyme elevation | About 3 out of 100 | About 8 out of 100 | About 16 out of 100 |
Source: (Epidiolex PI 2025) Phase 3 trials (Lennox-Gastaut and Dravet syndromes). Lower dose = 10 mg/kg/day; higher dose = 20 mg/kg/day. Human Trial
A separate meta-analysis found that compared with placebo, CBD was about 2.6 times more likely to cause diarrhea, about 3.6 times more likely to decrease appetite, and about 2.2 times more likely to cause drowsiness.
Source: (Chesney 2020) Meta-analysis of 12 randomized controlled trials, 803 participants. Human Trial
Side effects in older adults
A 2024 meta-analysis looking specifically at middle-aged and older adults found the most common side effects to be dizziness (about 12 out of 100) and sleepiness or fatigue (about 11 out of 100).
For seniors, dizziness and drowsiness are not just discomforts. They are fall risk factors. Falls are the leading cause of fatal and nonfatal injury in adults over 65.
Source: PMC11601816. Meta-analysis of cannabinoid adverse events in middle-aged and older adults. 2024.
Can CBD harm your liver?
In the FDA's own study of 201 healthy adults, about 5 to 6 out of 100 people who took CBD at doses close to what consumers buy (253 to 550 mg per day) developed elevated liver enzymes. No one in the placebo group had this problem. All elevations resolved after stopping CBD. Human Trial
Higher doses carry more risk. In Epidiolex clinical trials, liver enzyme elevations occurred in about 13 out of 100 patients at standard doses. When CBD was combined with the anti-seizure drug valproate, the rate rose to 21 to 30 out of 100.
At the typical doses found in over-the-counter CBD products (15 to 100 mg per day), the liver risk has not been studied in a controlled trial. It is likely lower, but it is not zero.
Sources: (FDA CDER 2025) (Epidiolex PI 2025)
Medical organizations advise discussing CBD with a doctor before use if you:
- Take any prescription medications
- Have liver disease or a history of elevated liver enzymes
- Are over 65
- Are pregnant or nursing
Based on cited sources. This is not personalized medical advice — discuss with your healthcare provider.
The FDA and clinical literature identify these as warning signs that may indicate a CBD-related problem:
- Notice unusual fatigue or yellowing of skin or eyes
- Experience severe stomach problems lasting more than 3 days
- Feel dizzy or faint repeatedly
- Develop unexplained bruising or bleeding (especially if on blood thinners)
- Notice dark-colored urine (tea or cola colored)
- Experience confusion or sudden changes in thinking
Based on cited sources. This is not personalized medical advice — discuss with your healthcare provider.
No one has studied CBD safety in people over 55
All major CBD clinical trials excluded adults over 55. The side effect rates listed here are from younger populations. Older adults process drugs more slowly due to reduced liver and kidney function, higher body fat, and lower protein binding. This means effects may be stronger and last longer than expected.
Key sources cited on this page
Page last reviewed: March 2026 · Authored by Claude (Anthropic AI) · Research methodology