What does the research say?
In a 24-week study with 200 participants, patients were randomly assigned to two groups: one group took 50 mg of pure CBD every day (study dose; not a personal recommendation), and the other took an inactive drug (placebo). The pain score went down by 0.4 points in the CBD group and by 1.1 points in the placebo group; in other words, the placebo group did a little better. This study counts as moderate evidence for pure CBD, but in a negative direction.
This result applies only to the low dose that was used; the effect of higher doses is unknown because they were not tested. Still, current data do not support using pure CBD at this dose for pain.
For THC-containing products, the evidence is weak. In a single-session lab study with 20 patients, THC-dominant cannabis, a THC and CBD mix, and CBD-dominant cannabis were inhaled through a vaporizer; none was clearly better than placebo for pain, and CBD reduced the pain-relieving effect of THC. In a small 24-person pilot study, an oil containing equal amounts of THC and CBD showed a promising sign for pain and sleep, but the differences between the groups were not statistically confirmed and most participants correctly guessed which group they were in; the result should be interpreted with caution and cannot be applied to pure CBD. In an 8-week study of 17 women in Brazil, a THC-rich cannabis oil reduced the impact of fibromyalgia on daily life more than an inactive oil; however, the study was very small, the product was not standardized, and because the two oils differed in color and taste, participants may have noticed which oil they were taking. In a single-dose lab study of 20 women in Israel, THC-rich oil did not reduce pain clearly more than an inactive oil; side effects such as nausea and reduced attention were common.
In a study of 81 patients with fibromyalgia, adding vaporized THC and CBD cannabis to the opioid painkiller oxycodone did not work better than using either treatment alone. One-third of those using cannabis stopped in the first weeks because of side effects. Of two small studies in 2008 and 2010 (40 and 31 people) with nabilone, a synthetic THC-like medicine, one reported improvement in pain and the other in sleep; the Cochrane review rated the certainty of this evidence as very low and noted that nabilone was stopped more often because of side effects. In real-world studies following hundreds of patients in Israel, Italy, Canada and the United Kingdom, those who stayed on treatment reported improvements in pain, sleep and mood. However, these studies had no comparison group, many patients stopped treatment or dropped out of follow-up over time, and some had ties to companies that supplied products or grew cannabis; so they count as weak evidence of effectiveness.
Strength of evidence: ●●●○ Moderate evidence. Finding: No effect found. What does this mean?
Ongoing research on this topic
Trials testing CBD for this topic on ClinicalTrials.gov: 3 under way (1 recruiting). A trial being under way does not show that CBD works.
- NCT06946940: Phase 2, recruiting, target 150 participants
- NCT07783295: Phase 2, not yet recruiting, target 80 participants
- NCT07498023: Phase 1/2, active, not recruiting, target 36 participants
Possible side effects and drug interactions
In the large fibromyalgia study, side effects were mild and similarly common in both groups. In the pilot study with the THC-containing oil, most side effects were also mild, and no serious side effects were seen. In healthy volunteers, CBD increased the risk of diarrhea. Side effects related to the nervous system and mental health are more common with THC-containing products. In fibromyalgia studies with THC and THC-like medicines, the most common side effects were dizziness, drowsiness, nausea, dry mouth and reduced attention; nabilone was stopped because of side effects more often than an inactive drug or amitriptyline. Side effects are also common in real-world registries: in the United Kingdom, nearly half of 497 patients reported at least one side effect, most often fatigue and dry mouth.
The fibromyalgia studies did not look at drug interactions separately. Because CBD can slow down how some medicines are broken down in the body, people who regularly take medicines for pain, sleep or mood should keep this in mind.
Interactions with medicines used for this condition
Interactions reported for these medicines in peer-reviewed publications and official prescribing information. A medicine that is not listed can still interact with CBD; tell your doctor about every medicine you take.
| Medicine | Importance | Warning | Source |
|---|---|---|---|
| Amitriptyline (tricyclic) (Laroxyl) | Caution | Amitriptyline: In healthy volunteers, a single 30 mg dose of CBD oil raised the blood level (AUC) of amitriptyline by 13% and its peak level by 17%; the effect is said to possibly be larger with ongoing use. Tell your doctor or pharmacist. | PMID 41398552 |
| Pregabalin (Lyrica) | Caution | Benzodiazepines, sleep medicines and sedatives: Drowsiness and sedation may increase together with CBD. Talk to your doctor before using them together. | DailyMed Epidiolex label 7.4, EMA Epidyolex SmPC 4.4 |
| SNRIs (venlafaxine, duloxetine, etc.) (Efexor XR, Cymbalta) | Information | SNRIs and tricyclic antidepressants: There are no clinical data on interactions between CBD and SNRIs or tricyclics other than amitriptyline (see the separate warning for amitriptyline). Still tell your doctor about all the medicines you take. | PMID 38868665 |
To check interactions with the medicines you take: CBD drug interaction checker.
How was CBD used in studies?
In the large study, pure CBD was taken as a tablet at 50 mg a day (study dose; not a personal recommendation) for 24 weeks. In the lab study, a single inhalation delivered, for example, 18.4 mg of CBD (study dose; not a personal recommendation). With the oil containing THC and CBD, the dose was adjusted gradually over four weeks; the final dose was between 0.5 and 3.5 mL a day (median 1 mL, or about 10 mg THC and 10 mg CBD; study dose, not a personal recommendation). The THC-like medicine nabilone was used at 0.5–2 mg a day (starting with 0.5 mg at bedtime), THC-rich oil under the tongue at an average of 3.6 drops a day (about 4.4 mg THC), and dronabinol (synthetic THC) at an average of 14.8 mg a day (study doses; not a personal recommendation).
Study details (for health professionals)
For pure CBD, the best evidence is negative: in a 200-person, 24-week RCT, CBD 50 mg a day reduced pain less than placebo. This result says nothing about higher doses; those doses were not tested. For THC-containing products there are only small pilot signals; adding vaporized THC+CBD to oxycodone gave no added benefit in an 81-patient open-label RCT, and one-third of those taking cannabis stopped because of side effects; in a single-dose experimental study, no product was clearly different from placebo. There are two small RCTs with nabilone, a synthetic THC-like medicine (40 people, 4 weeks vs. placebo; 31 people, 2 weeks vs. amitriptyline): pain and quality of life improved in one and sleep in the other; the Cochrane review (2016) rated this evidence as very low certainty. A THC-rich cannabis oil lowered the fibromyalgia impact score more than placebo in an 8-week RCT of 17 women (the product was not standardized; the two oils differed in color and taste); in a crossover lab study (20 people) with a single dose of THC oil under the tongue, the change in pain from baseline was not significantly different from the placebo session (the analysis in the full text does not support the 'superior to placebo' wording in the abstract); of the two central pain inhibition tests the study mainly measured, one did not change, and in the other only one indicator strengthened. In a randomized study without placebo comparing three different cannabinoid capsules (164 people, 64 with fibromyalgia), improvement was reported in all groups; it cannot be interpreted because there was no placebo. In analyses combining RCTs in fibromyalgia, there is no significant difference from placebo in pain (3 RCTs, 83 people; low certainty); the before–after improvement in a meta-analysis that also included uncontrolled studies (12 studies, 1,248 people) is not a comparison with placebo. In large real-world studies (Israel 367, United Kingdom 497, Canada 323, Italy 102 patients), those who stayed on treatment reported improvement; however, there was no control group, rates of stopping treatment or dropping out of follow-up were high (75% dropped out of follow-up within 12 months in Canada), and in the UK registry nearly half of patients reported side effects. In a German comparison of 120 inpatients, pain went down slightly more in those taking dronabinol (synthetic THC), but the groups were not randomly assigned. The result of a dronabinol RCT (NCT00176163) listed as completed on ClinicalTrials.gov (completion May 2009; fibromyalgia and low back pain) has been neither published nor posted to the registry. October 2026 search (PubMed, Cochrane, ClinicalTrials.gov, Europe PMC): 9 randomized studies with cannabinoids on this topic (6 placebo-controlled) and 1 non-randomized comparative study were found; all are in the table below. More than 10 systematic reviews specific to fibromyalgia or examining fibromyalgia separately were found; the 4 most recent and comprehensive (including Cochrane) and 4 large observational studies are also in the table.
Evidence assessment: Pure CBD: moderate (negative result)
CBD alone
Pure CBD 50 mg a day gave a worse result than placebo for fibromyalgia pain (difference −0.7; p=0.0028, in favor of placebo). No other controlled study comparing pure CBD with placebo in fibromyalgia was found (October 2026).
Products containing THC
In fibromyalgia, all RCTs comparing THC-containing products and nabilone with placebo or another drug are small (17–81 people) and short (from a single dose to 16 weeks). There are positive signs in a pilot study with a 1:1 THC:CBD oil, in a 17-person study with a THC-rich oil, and in two small studies with nabilone; in contrast, vaporized cannabis did not differ from placebo at a single dose, gave no added benefit when added to oxycodone, and with a single dose of THC oil under the tongue the change in pain was not clearly different from placebo. In analyses combining placebo-controlled studies, there was no significant difference from placebo in pain (low or very low certainty). The results cannot be applied to pure CBD.
Evidence: THC-containing: weak (small, short RCTs; inconsistent results)
Dose range in studies
Pure CBD 50 mg/day (24 weeks); 18.4 mg CBD in a single inhalation; with the 1:1 THC:CBD oil, final dose 5–35 mg THC + 5–35 mg CBD a day (median 10 + 10 mg; calculated from mL and product concentration); nabilone 0.5–2 mg/day; THC-rich oil about 4.4 mg THC/day on average; dronabinol 14.8 mg/day on average; single dose of THC under the tongue 0.2 mg/kg (average 13.1 mg)
Starting dose and titration
In Kurlyandchik 2026, over 4 weeks: started at 0.25 mL and increased by 0.25 mL every 2 days (up to 3.5 mL/day); in Skrabek 2008, nabilone from 0.5 mg to 2 × 1 mg over 4 weeks; in Chaves 2020, from 1 drop a day, increased by at most 1 drop every 10 days; in Bettstetter 2024, dronabinol over 13.4 days on average
These are doses researchers gave under medical supervision; they are not a recommended dose for you. "mg/kg/day" means milligrams per kilogram of body weight per day.
| Study | Participants | Product | Dose and titration | Duration | Result | Source |
|---|---|---|---|---|---|---|
| Rasmussen 2026 Double-blind, placebo-controlled, parallel, single-center RCT | 200 (100/100) Fibromyalgia | Plant-derived CBD tablet (CBD as the only active ingredient; THC content not reported in the abstract or registry) | 50 mg/day According to the plan in the registry, it was to start at 10 mg/day and increase every 3 days to reach 50 mg/day in 2 weeks (the full text of the article could not be read; the schedule actually used could not be verified) | 24 weeks | Pain decreased by −0.4 points with CBD and −1.1 points with placebo; difference in favor of placebo (−0.7; p=0.0028) Side effects: Mild, evenly distributed between the two groups | PMID 40846590, doi:10.1016/j.ard.2025.07.008, NCT04729179, no results in registry) |
| van de Donk 2019 Experimental, 4-arm crossover RCT | 25 enrolled; 20 completed (the 5 people who dropped out after the first visit were replaced) Fibromyalgia | Vaporized Bedrocan (THC), Bediol (THC+CBD), Bedrolite (CBD, <1 mg THC), placebo | Single inhalation (e.g., Bedrolite 18.4 mg CBD) | Single dose, 3 hours of observation | None was clearly different from placebo for spontaneous pain; CBD reduced the pain-relieving effect of THC. The reduction in pain was associated with the intensity of the feeling of intoxication. The products were provided in collaboration with the manufacturer; one of the authors is an employee of the manufacturer Side effects: Only with active products: coughing during inhalation 65–70%, sore throat and bad taste 25–35%, nausea in one-third of patients (all mild); most patients did not like the feeling of intoxication. 3 people stopped after the first visit because of dizziness and nausea; no serious side effects | PMID 30585986, doi:10.1097/j.pain.0000000000001464, Netherlands Trial Register NTR6091, EudraCT 2015-003811-39 (Spirocan) |
| Kurlyandchik 2026 Pilot, double-blind, placebo-controlled RCT | 24 randomized (12/12); 22 completed; efficacy analysis 10/10 Fibromyalgia (Australia; all participants women) | 1:1 THC:CBD oil (10 mg/mL each) | Single evening dose; final dose 0.5–3.5 mL (median 1 mL), i.e., 5–35 mg THC + 5–35 mg CBD a day (median 10 + 10 mg) (calculated from mL and product concentration) 4 weeks: started at 0.25 mL and increased by 0.25 mL every 2 days, up to 3.5 mL/day; then fixed for 12 weeks | 4 weeks of titration + 12 weeks at a fixed dose | Feasibility study. Primary outcomes: 24 people could be enrolled instead of the target 36; completion 92%, medication adherence reached the target, no serious side effects. Secondary (preliminary) efficacy: at week 12, the pain score was 1.02 points lower than placebo, but the difference was not significant (95% CI −2.73 to 0.69); at least 30% pain reduction 70% with cannabis vs. 40% with placebo; clinically meaningful improvement on FIQR 40% vs. 10%; sleep (PSQI) difference −3.09 (−6.42 to 0.25). Effect sizes were moderate to large, but the confidence intervals include zero and the analysis was 10 vs. 10 people. In both groups, 75% of participants correctly guessed which group they were in. The company supplying the product co-funded the lead author's PhD scholarship together with the university Side effects: Mostly mild, none serious | PMID 42142029, doi:10.1155/prm/7311235, ANZCTR ACTRN12623000345684, plasma endocannabinoid-like substance analysis of the same trial: Kurlyandchik 2026b, PMID 42464432 |
| van Dam 2024 Open-label RCT, 3 arms (oxycodone / cannabis / both together) | 81 (23 / 29 / 29) Fibromyalgia (Netherlands) | Vaporized cannabis (6.3% THC + 8% CBD) and/or oxycodone 5 mg tablet | For cannabis, 150 mg of plant material per session (about 9.5 mg THC + 12 mg CBD), up to 3 sessions a day in the first week, then up to 5; oxycodone up to 4 × 5 mg a day; dose self-titrated Adjusted by the patient | 6 weeks | No advantage of the combination over single treatments; it reduced oxycodone tablet use by 35%, but the total medication burden was highest; ≥1-point reduction in pain in half of patients Side effects: 31% of those taking cannabis and 13% of those taking oxycodone alone stopped within 2–3 weeks because of side effects | PMID 39654798, doi:10.3389/fpain.2024.1497111, WHO ICTRP NL7902, EU-CTR 2019-001861-33, PMID 36707893, SPIRAL) |
| Skrabek 2008 Double-blind, placebo-controlled, parallel RCT | 40 randomized (20/20); 15 people completed in the nabilone group; analysis of completers Fibromyalgia (Canada) | Nabilone (synthetic THC-like cannabinoid, oral capsule) | Started at 0.5 mg at bedtime and increased to 2 × 1 mg a day over 4 weeks Weekly increase: 0.5 mg → 2 × 0.5 mg → 0.5 + 1 mg → 2 × 1 mg | 4 weeks of treatment + 4 weeks of drug-free follow-up | At week 4, pain (VAS −2.04; p < 0.02), fibromyalgia impact score (FIQ −12.07; p < 0.02) and anxiety decreased from baseline in the nabilone group; there was no significant improvement in the placebo group (no direct between-group comparison in the abstract; Cochrane reports this as greater improvement than placebo). After 4 drug-free weeks, the gains were lost. Analysis of completers only (nabilone 15, placebo 18). Cochrane (Walitt 2016) rated the certainty of this evidence as very low Side effects: Side effects per person were higher in the nabilone group (1.58 at week 2, 1.54 at week 4; p < 0.05); most often drowsiness and dry mouth; 2 people in the nabilone group stopped because of side effects | PMID 17974490, doi:10.1016/j.jpain.2007.09.002, NCT00272207, commentary: Staud and Koo 2008, PMID 18521112 |
| Ware 2010 Double-blind, active drug (amitriptyline)-controlled, randomized crossover equivalence study | 31 enrolled; 29 completed (26 women) Fibromyalgia patients with chronic insomnia (Canada) | Nabilone (synthetic THC-like cannabinoid) and amitriptyline, by mouth, at bedtime | Nabilone 0.5–1.0 mg, amitriptyline 10–20 mg; before bedtime Started at 0.5 mg and increased to 1 mg if needed | 2 weeks on each drug, with a 2-week drug-free period in between | Sleep improved with both drugs; nabilone was better than amitriptyline on the insomnia severity scale (difference 3.2 points; 95% CI 1.2–5.3), borderline superior for feeling rested on waking, and no different for wakefulness. There was no difference in pain, mood or quality of life. No placebo group, short duration Side effects: More common with nabilone; most often dizziness, nausea and dry mouth; mostly mild–moderate | PMID 20007734, doi:10.1213/ANE.0b013e3181c76f70, NCT00381199 |
| Chaves 2020 Double-blind, placebo-controlled, parallel RCT | 18 randomized; 17 analyzed (8 cannabis, 9 placebo) Women with fibromyalgia, a low-income neighborhood (Florianópolis, Brazil) | THC-rich whole-plant cannabis oil (24.44 mg THC, 0.51 mg CBD per mL; not standardized, supplied by a patient association); placebo olive oil | Under the tongue, started at 1 drop a day (about 1.2 mg THC); at the end of the study an average of 3.6 drops (about 4.4 mg THC + 0.08 mg CBD/day) Increase of at most 1 drop every 10 days | 8 weeks | At week 8, the fibromyalgia impact score (FIQ, 0–100) fell from 75.5 to 30.5 in the cannabis group and from 70.2 to 61.2 with placebo; the between-group difference was significant (p = 0.005). A very small study (analysis with 17 people); the product was not standardized and its terpene content was not measured; according to the authors, the color and taste of the two oils did not fully match, which may have made it easier for participants to notice which group they were in. Registered after the study ended. No funding Side effects: In the cannabis group, drowsiness 87.5%, dizziness 25%, dry mouth 25%; no intolerable side effects reported. Drowsiness in 1 person with placebo | PMID 33118602, doi:10.1093/pm/pnaa303, ReBEC RBR-2f8mtn (registered after data collection, in March 2020) |
| Agbaria 2025 Double-blind, placebo-controlled, randomized crossover, single-dose lab study (subgroup without brain imaging from a registered 40-person trial) | 25 women enrolled; 23 took THC, 20 completed both sessions Women with fibromyalgia, aged 20–55, moderate–severe pain, not regular cannabis users (Israel) | THC-rich oil under the tongue (10% THC, 2% CBD) and placebo oil | Single dose 0.2 mg/kg THC (average 13.1 mg) | Single dose, measured 2 hours later; 2–6 weeks between sessions | The main measures were central pain inhibition tests: conditioned pain modulation (CPM) did not change with THC; the change from baseline in offset analgesia (OA) magnitude did not differ between the two sessions (treatment × time p = 0.32), while the OA index increased more after THC (p = 0.004). The Short-Form McGill pain score fell from 20.5 to 9.5 in the THC session and from 22.7 to 17.1 in the placebo session; the difference between sessions in change from baseline was not significant (treatment × time p = 0.50). This analysis in the full text does not support the abstract's statement that 'THC was significantly superior to placebo for pain (p = 0.02).' Participants were not asked what they had received; frequent side effects may have made it easier for them to notice which oil they took Side effects: After THC, nausea 57%, reduced attention 52%, headache 35%, mental fogginess 26%, drowsiness 22%; 3 people stopped after the THC session because of side effects that were not severe but were intolerable; no notable side effects with placebo | PMID 41199355, doi:10.1186/s42238-025-00348-x, NCT05644054, no results in registry) |
| Kruger 2026 Randomized study comparing three cannabinoid formulations without placebo (a real-world data study according to the authors); blinding not stated in the abstract | 276 enrolled; 164 people who completed the questionnaires and continued the product were analyzed (64 fibromyalgia, 25 rheumatoid arthritis, 75 knee/hip osteoarthritis) Adults living in California diagnosed with fibromyalgia, rheumatoid arthritis or knee/hip osteoarthritis (USA) | Oral capsule, three formulations: 1) 12.5 mg CBD + 12.5 mg THC; 2) 10 mg THCA + 10 mg CBDA (unheated acid forms of THC and CBD) + 5 mg CBG + 3 mg CBC; 3) 10 mg CBD + 10 mg CBDA | Amounts above per capsule; daily number of capsules not reported (in the abstract) Not reported (in the abstract) | 12 weeks | In the per-protocol analysis, improvement from baseline in all symptoms except cognitive function (small to large effect); most effects did not differ between products or pain types, while there was a difference between products for sleep. Because there was no placebo group, how much of the improvement came from the products is unknown; 39% of those enrolled did not complete the questionnaires; fibromyalgia-specific numbers are not in the abstract; four of six authors are tied to a company (MoreBetter), and the authors reported no conflict of interest Side effects: Not reported (in the abstract) | PMID 42140793, doi:10.1016/j.clinthera.2026.04.018 |
| Walitt 2016 (Cochrane) Cochrane systematic review (RCTs lasting at least 4 weeks; search through April 2016) | 72 (2 RCTs) Adults with fibromyalgia | Nabilone (in both studies); no suitable RCTs with herbal cannabis or other cannabinoids were found | Nabilone 0.5–2 mg/day (in Ware 2010, 0.5–1 mg at bedtime; in Skrabek 2008, from 0.5 mg at bedtime to 2 × 1 mg a day) | There is no convincing, unbiased, high-quality evidence that nabilone works in fibromyalgia; all outcomes are very low certainty. In one study, pain and quality of life improved more than with placebo; in the comparison with amitriptyline, sleep was better with nabilone, with no difference in pain. As of October 2026, there is no update on PubMed Side effects: Dropouts due to side effects 4/52 with nabilone, 1/20 with placebo, 0/32 with amitriptyline; most often dizziness, nausea, dry mouth and drowsiness; no serious side effects reported. According to the authors, nabilone was not well tolerated in fibromyalgia | PMID 27428009, doi:10.1002/14651858.CD011694.pub2 | |
| Giossi 2022 Systematic review and meta-analysis (8 RCTs in chronic primary pain; search through October 2021); fibromyalgia subgroup analysis | 240 (all); fibromyalgia pain analysis 83 people, 3 RCTs Chronic primary pain (fibromyalgia, irritable bowel syndrome, complex regional pain syndrome, etc.) | Cannabinoids (nabilone, dronabinol, THC-rich oil, vaporized cannabis, CBD chewing gum) | Variable | In fibromyalgia, pain was not significantly different from placebo (−0.70 on a 0–10 scale; 95% CI −1.54 to 0.12; 3 RCTs, 83 people; low certainty); difference in fibromyalgia impact score −21.7 (−46.2 to 2.8; 2 RCTs). In parallel studies lasting at least 4 weeks, a small reduction in pain (−0.82; −1.41 to −0.24; 2 RCTs, 58 people). Across all chronic primary pain, the difference was also not significant (−0.64; −1.30 to 0.02) Side effects: No significant difference from placebo in dropouts due to side effects (OR 2.15; 0.44–10.65; all chronic primary pain) | PMID 36129666, doi:10.1007/s40122-022-00434-5 | |
| Duarte 2026 Systematic review (RCTs only; search through March 2024), meta-analysis of 2 studies; PROSPERO CRD42024525247 | 4 RCTs (Skrabek 2008, Ware 2010, Chaves 2020, van Dam; the last via its protocol publication, PMID 36707893) Fibromyalgia (ACR 1990, 2010 or 2016 criteria) | Nabilone, THC-rich oil, vaporized THC + CBD cannabis (Bediol) | Variable | The true effect of cannabis products on pain, disease impact or insomnia could not be determined from four small RCTs. In the pooled analysis of two placebo-controlled studies, the difference from placebo in pain and fibromyalgia impact score was not significant; evidence very low certainty (risk of bias, inconsistency, imprecision). The pooled analysis is methodologically weak: because the spread of change scores was not reported, baseline spread and p values were used; single-dose studies were excluded Side effects: Side effects of the included studies were reported one by one (most often drowsiness, dry mouth, dizziness, nausea); no pooled analysis | PMID 42370077, doi:10.1016/j.ero.2026.01.016 | |
| Lam 2026 Systematic review and meta-analysis (2 RCTs + 10 observational studies, 14 comparisons); PROSPERO CRD42024495525 | 1,248 Fibromyalgia | Cannabinoids (various) | Variable | Reduction in pain intensity compared with before treatment (SMD −1.41; 95% CI −1.98 to −0.84); improvement also in sleep, anxiety, depression and quality of life. The analysis was mostly based on observational studies without a control group and on before–after differences; it is not a comparison with placebo. Evidence is low certainty, with very large heterogeneity between studies Side effects: Common: dizziness, dry mouth, drowsiness; serious side effects rare | PMID 42013320 | |
| Bettstetter 2024 Retrospective, non-randomized comparative study (patients who did and did not receive dronabinol) | 120 (62 dronabinol, 58 comparison) Fibromyalgia patients receiving inpatient multimodal pain treatment in the hospital (Germany, 2017–2018) | Dronabinol (synthetic THC; more than 90% as capsules, the rest as oily drops) | Average 14.8 mg/day (2.6–31.3 mg) Increased gradually over an average of 13.4 days | During inpatient multimodal pain treatment (average about 2 weeks) | Pain (0–10) fell from 6.0 to 4.2 in the dronabinol group and from 5.6 to 4.6 in the comparison group; the reduction was significantly greater with dronabinol, as were improvements in depression and quality of life; no difference in anxiety or sleep. In 5 of 7 pain medicine groups, dose reduction or stopping was more common in the dronabinol group. The groups were not randomly assigned and differed at baseline (in the dronabinol group, the illness was more chronic and more previous drug treatments had been tried); everyone was in an intensive treatment program at the same time Side effects: Not systematically recorded; 2 patients who stopped dronabinol because of side effects were excluded from the analysis | PMID 37289246, doi:10.1007/s00482-023-00727-4 |
| Sagy 2019 Prospective observational cohort (medical cannabis clinic) | 367 started; response rate to the month-6 questionnaire 70.8% Fibromyalgia (Israel, 2015–2017; 82% women) | Medical cannabis: 67% dried flower (smoked or vaporized), 20% oil, 12% both; most prescriptions THC-rich | At month 6, median 1,000 mg cannabis/day; median 140 mg THC and 39 mg CBD/day Started at a low dose (e.g., 1 drop 3 times a day) and increased gradually | 6 months | Pain (0–10) fell from a median of 9 to 5; 81.1% of those assessed reported at least moderate improvement. 22.2% of opioid users stopped or reduced opioids. No control group; one of the authors is an employee of the company supplying the product, and one is an advisory board member Side effects: Most common were dizziness 7.9%, dry mouth 6.7% and nausea/vomiting 5.4%; stopping treatment before 6 months 7.6% | PMID 31195754, doi:10.3390/jcm8060807 |
| Giorgi 2020 Prospective observational study (consecutive patients) | 102 Fibromyalgia patients with ongoing pain despite standard pain treatment (Italy, Milan) | Oil-diluted cannabis extracts: Bedrocan (22% THC, <1% CBD) and Bediol (6.3% THC, 8% CBD) | Not reported (in the abstract) Not reported (in the abstract) | 6 months | At month 6, 64% were still on treatment; significant improvement on the sleep scale (PSQI) in 44% of patients and on the fibromyalgia impact scale (FIQR) in 33%; moderate improvement in anxiety and depression in 50%; 47% of patients reduced or stopped their other pain medicines. No control group Side effects: Mild side effects in one-third; no change in treatment needed | PMID 32116208 |
| Sotoodeh 2023 Prospective cohort | 323; 75% had dropped out of follow-up by month 12 Fibromyalgia patients starting medical cannabis under a doctor's supervision (Canada, Montreal) | Medical cannabis (composition not in the abstract) | Not reported (in the abstract) Not reported (in the abstract) | 12 months | The reduction in pain was partly explained by a reduction in sleep problems and negative affect (anxiety, depression) over the same period (both p < 0.001). The size of the change in pain is not in the abstract. By month 12, 75% of patients had dropped out of follow-up; according to the authors, the results therefore cannot be generalized to all patients. No control group; two authors are tied to a cannabis company (Canopy Growth) Side effects: Not reported (in the abstract) | PMID 35876631, doi:10.1002/acr.24985 |
| Varadpande 2026 Prospective patient registry case series (UK Medical Cannabis Registry) | 497 Fibromyalgia patients who had not benefited enough from licensed treatments (United Kingdom; 69% women, 54% not working) | Prescription cannabis products: oil, dried flower or both (most often CBD-rich and THC-rich oils, THC-rich flower) | Median CBD 20 mg/day (at baseline) → 25 mg/day (month 18); median THC 2 mg/day → 112.5 mg/day Not reported; THC dose increased markedly over 18 months | 18 months | Improvement from baseline on all scales (p < 0.01); at month 18, fibromyalgia symptom severity fell from 9.1 to 8.4 and the widespread pain index from 14.0 to 13.0; improvement was greatest at month 1 and then lessened. Those taking more than 25 mg of CBD a day were more likely to improve on fibromyalgia scales. No control group; missing responses were counted as 'no change'; the registry belongs to a private clinic in the same corporate group as the manufacturer of the most frequently prescribed products, and most of the authors work there Side effects: 45.7% of patients reported at least one side effect (2,100 in total; 85% mild–moderate, 14.6% severe, 2 life-threatening: anxiety and lung infection); most common were fatigue 30.8%, dry mouth 27.6% and impaired concentration 26.2% | PMID 41343025, doi:10.1007/s10067-025-07846-6, Earlier fibromyalgia analyses of the same registry: Wang 2023, PMID 37199833, Sridharan 2025, PMID 39417761, products from a single manufacturer, PMID 39432707 |
Reported side effects
- In healthy volunteers, CBD increased the risk of diarrhea (RR 5.85); a non-significant trend toward more abdominal pain and headache (Sawaira 2026, PMID 41789242)
- Psychiatric and nervous system side effects are more common with THC-containing products (Filippini 2022, PMID 35510826); the likelihood of side effects increased with any cannabinoid (OR 1.75; Wilson 2026, PMID 41856154). In fibromyalgia, dropouts due to side effects were 4/52 with nabilone and 1/52 in control groups (Walitt 2016); with vaporized THC + CBD cannabis, 31% dropped out in the first 2–3 weeks (van Dam 2024); after a single dose of THC oil, nausea 57% and reduced attention 52% (Agbaria 2025); in the UK patient registry, 45.7% of patients reported side effects (Varadpande 2026)
Who should be careful
- High doses and market doses cannot be compared: in low-dose (≤175 mg/day) studies, plasma levels were 5–100 times lower than with the 20 mg/kg Epidiolex dose (Warren 2026, PMID 42473010)
- Anyone taking a medicine long-term should talk to a doctor before starting; the studies on this page did not systematically assess interactions
- Using pure CBD at 50 mg/day as a painkiller is not supported
Drug interactions
- The studies on this page did not systematically assess drug interactions; details are in the site's drug interactions section
Abbreviations: RCT, randomized controlled trial (a study in which participants are assigned to groups by chance); placebo, an inactive substance; SMD, OR and RR, effect measures used in analyses that pool studies; CYP, liver enzymes that break down medicines.
If you are considering CBD
- Do not stop the medicines and other treatments you have chosen together with your doctor; there is no evidence that CBD replaces them.
- If you take medicines for pain, sleep or mood, review CBD together with your doctor or pharmacist.
- Check the product label and certificate of analysis (COA); find out whether it contains THC.
- A product being marketed as 'good for fibromyalgia' does not mean this has been shown by research.
Choose your age group, medicines and situation to prepare a short summary you can take to your doctor. Nothing you enter is sent anywhere.
Bottom line
The largest study of pure CBD in fibromyalgia showed no benefit at a low dose. Research on higher doses and THC-containing products is still at an early stage. The healthiest approach is to review ways of coping with your pain together with your doctor.
Frequently asked questions
Does CBD oil work for fibromyalgia?
Current data do not support it. In a 200-person, 24-week study, pain went down less in people taking low-dose pure CBD than in those taking an inactive drug (placebo). Higher doses have not been tested yet, so nothing can be said about them.
Does a higher dose of CBD work for fibromyalgia?
It is not known. The dose used in the large study was low, and higher doses were not tested. Only new studies can answer this question.
Do THC-containing products help fibromyalgia pain?
The evidence is weak. In a single-session lab study, none of the inhaled cannabis products was clearly better than placebo for pain. A 24-person pilot study with an oil containing THC and CBD and a study of 17 women with a THC-rich oil showed promising signs; in two small studies with nabilone, a THC-like medicine, pain or sleep also improved. But all of these studies are small and short; when they are combined, no clear difference in pain is seen compared with an inactive drug (placebo). They need to be confirmed by larger studies.
Does CBD have side effects in fibromyalgia?
In the large study, side effects were mild and similarly common in the CBD and placebo groups. In healthy volunteers, CBD increased the risk of diarrhea. Side effects related to the nervous system and mental health are more common with THC-containing products: in fibromyalgia studies, dizziness, drowsiness, nausea, dry mouth and reduced attention were common. One-third of those using vaporized cannabis stopped in the first weeks because of side effects; in a patient registry in the United Kingdom, nearly half of patients also reported at least one side effect.
Can CBD oil be prescribed for fibromyalgia in Turkey?
In Turkey, cannabis-derived products are regulated by the Kenevirden Elde Edilen Ürünlere Dair Yönetmelik (Regulation on Products Derived from Hemp) dated January 31, 2026. These products, including CBD, can be sold only in pharmacies. Those in the medicine and health product category are dispensed with a prescription; the regulation does not state a prescription requirement for supplement products and cosmetics with a THC content of no more than 0.3%. As of October 2026, there is no approved (licensed) CBD medicine in Turkey. If you are thinking of using it, talk to your doctor first.
References
Show 18 references
- Rasmussen 2026. Double-blind, placebo-controlled, parallel, single-center RCT. PMID 40846590, doi:10.1016/j.ard.2025.07.008, NCT04729179, no results in registry)
- van de Donk 2019. Experimental, 4-arm crossover RCT. PMID 30585986, doi:10.1097/j.pain.0000000000001464, Netherlands Trial Register NTR6091, EudraCT 2015-003811-39 (Spirocan)
- Kurlyandchik 2026. Pilot, double-blind, placebo-controlled RCT. PMID 42142029, doi:10.1155/prm/7311235, ANZCTR ACTRN12623000345684, plasma endocannabinoid-like substance analysis of the same trial: Kurlyandchik 2026b, PMID 42464432
- van Dam 2024. Open-label RCT, 3 arms (oxycodone / cannabis / both together). PMID 39654798, doi:10.3389/fpain.2024.1497111, WHO ICTRP NL7902, EU-CTR 2019-001861-33, PMID 36707893, SPIRAL)
- Skrabek 2008. Double-blind, placebo-controlled, parallel RCT. PMID 17974490, doi:10.1016/j.jpain.2007.09.002, NCT00272207, commentary: Staud and Koo 2008, PMID 18521112
- Ware 2010. Double-blind, active drug (amitriptyline)-controlled, randomized crossover equivalence study. PMID 20007734, doi:10.1213/ANE.0b013e3181c76f70, NCT00381199
- Chaves 2020. Double-blind, placebo-controlled, parallel RCT. PMID 33118602, doi:10.1093/pm/pnaa303, ReBEC RBR-2f8mtn (registered after data collection, in March 2020)
- Agbaria 2025. Double-blind, placebo-controlled, randomized crossover, single-dose lab study (subgroup without brain imaging from a registered 40-person trial). PMID 41199355, doi:10.1186/s42238-025-00348-x, NCT05644054, no results in registry)
- Kruger 2026. Randomized study comparing three cannabinoid formulations without placebo (a real-world data study according to the authors); blinding not stated in the abstract. PMID 42140793, doi:10.1016/j.clinthera.2026.04.018
- Walitt 2016 (Cochrane). Cochrane systematic review (RCTs lasting at least 4 weeks; search through April 2016). PMID 27428009, doi:10.1002/14651858.CD011694.pub2
- Giossi 2022. Systematic review and meta-analysis (8 RCTs in chronic primary pain; search through October 2021); fibromyalgia subgroup analysis. PMID 36129666, doi:10.1007/s40122-022-00434-5
- Duarte 2026. Systematic review (RCTs only; search through March 2024), meta-analysis of 2 studies; PROSPERO CRD42024525247. PMID 42370077, doi:10.1016/j.ero.2026.01.016
- Lam 2026. Systematic review and meta-analysis (2 RCTs + 10 observational studies, 14 comparisons); PROSPERO CRD42024495525. PMID 42013320
- Bettstetter 2024. Retrospective, non-randomized comparative study (patients who did and did not receive dronabinol). PMID 37289246, doi:10.1007/s00482-023-00727-4
- Sagy 2019. Prospective observational cohort (medical cannabis clinic). PMID 31195754, doi:10.3390/jcm8060807
- Giorgi 2020. Prospective observational study (consecutive patients). PMID 32116208
- Sotoodeh 2023. Prospective cohort. PMID 35876631, doi:10.1002/acr.24985
- Varadpande 2026. Prospective patient registry case series (UK Medical Cannabis Registry). PMID 41343025, doi:10.1007/s10067-025-07846-6, Earlier fibromyalgia analyses of the same registry: Wang 2023, PMID 37199833, Sridharan 2025, PMID 39417761, products from a single manufacturer, PMID 39432707
Research history
Here we record what changed on this page, when and why, with dates. The newest change is at the top.
Display fix: internal working notes left over from the previous cleanup were removed; content and evidence did not change.
Display fix: internal working file names left in the text were removed; content and evidence did not change.
In October 2026, PubMed, Cochrane, ClinicalTrials.gov and Europe PMC were systematically searched; 14 studies were added: 2 randomized studies with the THC-like medicine nabilone, 2 with THC-containing cannabis oils and 1 comparing three cannabinoid capsules, 1 non-randomized comparison with dronabinol, 4 systematic reviews including Cochrane, and 4 large real-world studies. Among existing rows, the daily dose and result numbers of the THC and CBD oil study were added from the full text, the number of people and side effects of the vaporized cannabis study were corrected, and registry numbers were added to four rows. The conclusion and the strength of evidence did not change.
Related studies: Skrabek 2008, published February 2008 (PMID 17974490, doi:10.1016/j.jpain.2007.09.002, NCT00272207, commentary: Staud and Koo 2008, PMID 18521112); Ware 2010, published February 2010 (PMID 20007734, doi:10.1213/ANE.0b013e3181c76f70, NCT00381199); Chaves 2020, published October 2020 (PMID 33118602, doi:10.1093/pm/pnaa303, ReBEC RBR-2f8mtn (registered after data collection, in March 2020)); Agbaria 2025, published November 6, 2025 (PMID 41199355, doi:10.1186/s42238-025-00348-x, NCT05644054, no results in registry)); Kruger 2026, published September 2026 (PMID 42140793, doi:10.1016/j.clinthera.2026.04.018); Walitt 2016 (Cochrane), published July 18, 2016 (PMID 27428009, doi:10.1002/14651858.CD011694.pub2); Giossi 2022, published December 2022 (PMID 36129666, doi:10.1007/s40122-022-00434-5); Duarte 2026, published March 2026 (PMID 42370077, doi:10.1016/j.ero.2026.01.016); Lam 2026, published April 2026 (PMID 42013320); Bettstetter 2024, published August 2024 (PMID 37289246, doi:10.1007/s00482-023-00727-4); Sagy 2019, published June 5, 2019 (PMID 31195754, doi:10.3390/jcm8060807); Giorgi 2020, published January–February 2020 (PMID 32116208); Sotoodeh 2023, published July 2023 (PMID 35876631, doi:10.1002/acr.24985); Varadpande 2026, published March 2026 (PMID 41343025, doi:10.1007/s10067-025-07846-6, Earlier fibromyalgia analyses of the same registry: Wang 2023, PMID 37199833, Sridharan 2025, PMID 39417761, products from a single manufacturer, PMID 39432707)
Older changes (4)
The names of the result labels were simplified: the "No benefit found" label on this page became "No effect found". The assessment did not change.
PubMed and ClinicalTrials.gov were searched for newly published and previously missed clinical studies. Study added: van Dam 2024. The conclusion and the strength of evidence did not change.
Related studies: van Dam 2024, published 2024 (PMID 39654798, doi:10.3389/fpain.2024.1497111, WHO ICTRP NL7902, EU-CTR 2019-001861-33, PMID 36707893, SPIRAL))
A technical phrase ("failed to beat placebo") was replaced with a clearer one ("was not clearly different from placebo"). The year of a publication named on the page was corrected to the journal's print year instead of the online publication year. The conclusion and the strength of evidence did not change.
Page published. In this first review, 3 studies were examined.