Cannabis may offer modest relief for chronic pain
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- Reviewed by Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
Many people use cannabis-based products such as marijuana for pain relief. However, the science to back up their effectiveness is slim. Cannabis products contain tetrahydrocannabinol (THC), cannabidiol (CBD), or both. They can be derived from the cannabis plant or made in a laboratory (synthetic).
A review of 25 studies involving over 2,300 participants published Dec. 23, 2025, in Annals of Internal Medicine, evaluated how well these products work for chronic pain, defined as pain lasting longer than three months. For the review, the researchers categorized cannabis products based on the ratio of THC to CBD, the source (synthetic or extracted from plants), and how the product was taken (orally, as a spray applied inside the mouth, or as a topical product applied to the skin).
Synthetic products taken orally that contained higher levels of THC relative to CBD offered small improvements in chronic pain levels. Plant-derived products taken by spray inside the mouth with similar amounts of THC and CBD also slightly reduced pain. Effects such as sleepiness, dizziness, and nausea were more common with high-THC products. Combination products with higher levels of CBD than THC and those with CBD alone had little or no effect on chronic pain.
Image: © skodonnell/Getty Images
About the Author
Lynne Christensen, Staff Writer
About the Reviewer
Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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