CBD Oil for Knee Arthritis Pain: A Rigorous Trial Shows No Benefit Over Placebo
In a 60-day double-blind trial, CBD-rich cannabis oil (45 mg/day) did not reduce knee osteoarthritis pain more than placebo—though both groups improved.
Quick Facts
What This Study Found
This Brazilian trial is one of the most rigorous tests of CBD for osteoarthritis pain. Patients with knee osteoarthritis were randomized to either a full-spectrum CBD-rich cannabis oil (45 mg CBD daily) or placebo for 60 days.
The primary outcome—pain intensity measured by the WOMAC questionnaire—improved in both groups, but there was no statistically significant difference between CBD and placebo. Secondary outcomes including pain on a visual analogue scale, depression (BDI), sleep quality (PSQI), and quality of life also showed no significant between-group differences.
This is a null result, and it's an important one. The study was well-designed (double-blind, randomized, placebo-controlled), used a validated pain measure, and ran for a reasonable duration. The fact that both groups improved underscores the power of the placebo effect in pain trials—and the importance of having a control group.
The dose (45 mg CBD/day) is modest by current clinical standards, and the formulation was a full-spectrum oil (containing small amounts of other cannabinoids). Whether higher doses, different formulations, or different CBD:THC ratios would produce different results remains an open question.
Key Numbers
60-day trial. CBD dose: 45 mg/day full-spectrum oil. No significant difference between CBD and placebo on WOMAC pain, VAS pain, depression, sleep quality, or quality of life. Both groups improved from baseline.
How They Did This
Double-blind, randomized, placebo-controlled trial. Knee osteoarthritis patients randomized to CBD-rich full-spectrum cannabis oil (45 mg CBD/day) or placebo for 60 days. Primary outcome: WOMAC pain intensity. Secondary outcomes: VAS pain, Beck Depression Inventory, Pittsburgh Sleep Quality Index, SF-12 quality of life components.
Why This Research Matters
Osteoarthritis is the most common form of arthritis and a leading reason people try CBD products. This trial provides rigorous evidence that at least at this dose and formulation, CBD doesn't outperform placebo for knee OA pain. Given the billions spent on CBD products marketed for joint pain, negative results from well-designed trials serve an important public health function.
The Bigger Picture
This null result for CBD in osteoarthritis contrasts with RTHC-00158's finding that THC:CBD oil specifically improved pain in cancer patients. The difference may be the THC component—cancer pain and osteoarthritis pain involve different mechanisms, and THC's analgesic properties may be more relevant for some pain types than CBD alone. RTHC-00170's finding that neuropathic pain patients use cannabis more intensively than other pain patients also suggests that cannabis may be more useful for nerve-related pain than for the inflammatory/mechanical pain of osteoarthritis.
What This Study Doesn't Tell Us
The 45 mg/day CBD dose is relatively low—some clinical protocols use 150–600 mg/day. Full-spectrum oil means other cannabinoids were present but at low, variable levels. 60-day duration may not capture longer-term effects. Single center in Brazil. The study may have been underpowered (sample size not specified in the abstract). Placebo response was substantial, as is typical in pain trials.
Questions This Raises
- ?Would higher CBD doses show a benefit?
- ?Does the addition of THC change the result for osteoarthritis pain?
- ?Are there osteoarthritis subgroups (inflammatory vs. mechanical, early vs. advanced) that might respond differently to cannabinoids?
Trust & Context
- Key Stat:
- Evidence Grade:
- Double-blind, randomized, placebo-controlled trial—strong design producing a well-powered null result.
- Study Age:
- Published in 2025 with a current clinical protocol.
- Original Title:
- Effects and safety of a CBD-rich Cannabis sativa oil in knee osteoarthritis: a double-blind, randomized, placebo-controlled trial - CANOA - cannabis for osteoarthritis.
- Published In:
- Frontiers in pharmacology, 16, 1657065 (2025) — Frontiers in Pharmacology is a reputable, peer-reviewed journal focusing on drug research and pharmacological studies.
- Authors:
- Mojoli, Andrés, Haider, Osvaldo, Fakih, Yasmin, Luz Gonçalves, Maria Victoria, Zepeda Rojas, Bruno, Xaia, Giovanna, Krefta, Emanuelly, Bicca, Maíra Assunção, Lopes de Mari, Thiago, Ferreira, Charles Francisco, Cezar-Dos-Santos, Fernando, Toci, Aline Theodoro, Nascimento, Francisney Pinto
- Database ID:
- RTHC-07163
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Read More on RethinkTHC
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Cite This Study
https://rethinkthc.com/research/RTHC-07163APA
Mojoli, Andrés; Haider, Osvaldo; Fakih, Yasmin; Luz Gonçalves, Maria Victoria; Zepeda Rojas, Bruno; Xaia, Giovanna; Krefta, Emanuelly; Bicca, Maíra Assunção; Lopes de Mari, Thiago; Ferreira, Charles Francisco; Cezar-Dos-Santos, Fernando; Toci, Aline Theodoro; Nascimento, Francisney Pinto. (2025). Effects and safety of a CBD-rich Cannabis sativa oil in knee osteoarthritis: a double-blind, randomized, placebo-controlled trial - CANOA - cannabis for osteoarthritis.. Frontiers in pharmacology, 16, 1657065. https://doi.org/10.3389/fphar.2025.1657065
MLA
Mojoli, Andrés, et al. "Effects and safety of a CBD-rich Cannabis sativa oil in knee osteoarthritis: a double-blind, randomized, placebo-controlled trial - CANOA - cannabis for osteoarthritis.." Frontiers in pharmacology, 2025. https://doi.org/10.3389/fphar.2025.1657065
RethinkTHC
RethinkTHC Research Database. "Effects and safety of a CBD-rich Cannabis sativa oil in knee..." RTHC-07163. Retrieved from https://rethinkthc.com/research/mojoli-2025-effects-and-safety-of
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.