We compared common claims about CBD with the research. Each one comes with its source.
Last updated: We don’t sell products.
False
Based on current evidence, CBD does not cure cancer or shrink tumors. In an additional analysis of a controlled study of pure CBD oil in patients with advanced cancer, disease progression and survival did not change. The American Society of Clinical Oncology (ASCO) strongly recommends that cannabis products not be used in place of cancer treatment.
Source: Braun 2024, PMID 38478773; O'Leary 2024, PMID 38307703
False
Pure CBD was found to have a very low risk of misuse and addiction: in frequent marijuana users, 200–800 mg of CBD produced no “liking” effect different from placebo. Adults who took 1,500 mg of CBD a day for four weeks and then stopped showed no withdrawal symptoms, and the World Health Organization also found no potential for addiction with pure CBD. These results apply to pure CBD; they cannot be generalized to products that contain THC.
Source: Babalonis 2017, PMID 28088032; FDA 2026 (Epidiolex label), dailymed.nlm.nih.gov; WHO 2018, www.who.int
False
Pure CBD does not cause intoxication the way the THC in marijuana does; even with single doses of up to 1,500 mg, volunteers did not feel intoxicated, and CBD did not turn into THC in the body. The World Health Organization recommended that pure CBD not be placed under international drug control. However, CBD can cause sleepiness, and “CBD” products that contain THC can cause intoxication.
Source: McCartney 2022, PMID 35637624; Sholler 2022, PMID 34089060; WHO 2018, www.who.int
False
Natural does not mean safe: in a controlled study in healthy adults, about 6% of those who took 5 mg/kg of CBD a day had clearly raised liver values. CBD can cause sleepiness and can change the blood levels of some medicines. The European Food Safety Authority set a provisional safe level of about 2 mg a day for a 70 kg adult, for supplements that are at least 98% pure and contain no nanoparticles; safety could not be established for people under 25, people who are pregnant or breastfeeding, and people who take medicines.
Source: Florian 2025, PMID 40622698; FDA 2026 (Epidiolex label), dailymed.nlm.nih.gov; EFSA 2026, www.efsa.europa.eu
False
In two small studies on public-speaking anxiety, only a medium dose seemed to work; lower and higher doses did not. Side effects, on the other hand, increase with the dose: with the approved CBD medicine, raised liver values were seen in 17% of people at 20 mg/kg a day and in 1% at 10 mg/kg. More is not better; the dose is decided together with a doctor, starting low and increasing slowly.
Source: Zuardi 2017, PMID 28553229; Linares 2019, PMID 30328956; FDA 2026 (Epidiolex label), dailymed.nlm.nih.gov
False
Hemp seeds do not naturally contain CBD; the very small amount in seed oil gets in from other parts of the plant during processing. In a study that tested 30 commercial seed oils, total cannabis compounds were 9–279 mg per kilogram; that is less than one hundredth of the CBD in a 5% CBD oil. Seed oil is a food oil; results from CBD studies cannot be applied to it.
Source: FDA 2024, www.fda.gov; Lindekamp 2024, PMID 38588664
Insufficient evidence
The idea that the substances in the plant work better together (the “entourage effect”) has not been proven in controlled studies in humans; reviews stress that it should not be presented as if it were proven. When observational data in epilepsy were looked at using the measure of seizures dropping by at least half, there was no difference between mixed extracts and pure CBD. What’s more, because full-spectrum products can contain THC, the risk of a positive drug or doping test is higher.
Source: Simei 2024, PMID 37535820; Pamplona 2018, PMID 30258398; Wolinsky 2026, PMID 40704705
False
CBD can change the blood levels of some medicines by affecting the liver enzymes that process them; for example, it raises the active breakdown product of the epilepsy medicine clobazam about 3-fold. In a patient taking the blood thinner warfarin, the clotting value (INR) rose after starting CBD, and the warfarin dose had to be lowered; even a single 30 mg dose of CBD slightly raised the blood level of an antidepressant. Tell your doctor or pharmacist about every medicine you take.
Source: FDA 2026 (Epidiolex label), dailymed.nlm.nih.gov; Grayson 2018, PMID 29387536; Gorbenko 2026, PMID 41398552
False
Of 84 CBD products bought online, the label matched the actual content for only about one in three; THC was found in one in five. Nearly half of 186 CBD oils collected in Europe over ten years did not contain the amount of CBD stated on the label. Products with an independent laboratory certificate of analysis (COA) may be more reliable, but substances not listed on the certificate can still turn up.
Source: Bonn-Miller 2017, PMID 29114823; Binova 2026, PMID 42611266; Gillham 2026, PMID 40920736
False
The benefit of CBD has been shown in controlled studies only in some severe childhood epilepsies (Dravet, Lennox-Gastaut, tuberous sclerosis); the approved medicine is also authorized only for these. According to a comprehensive review published in 2026, controlled studies do not support the use of cannabis products for most of the conditions they are promoted for. Of the topics reviewed in this guide, pure CBD has shown benefit in only three, and these are those three types of epilepsy.
Source: Solmi 2023, PMID 37648266; Hsu 2026, PMID 41296368; FDA 2026 (Epidiolex label), dailymed.nlm.nih.gov
Warnings sent about CBD products sold with claims to treat diseases, and some product test results.
The expert committee's assessment of CBD's safety and risk of dependence (PDF).
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