Medical marijuana extracts “meaningfully” improve cancer-related symptoms such as sleep difficulties and anxiety—though responses varied among patients depending on personal preferences for individual cannabinoid content of the extracts—according to a new study
Researchers at the University of British Columbia, University of Ottawa, University of Manitoba and Queen’s University investigated the impact of extracts containing different concentrations of THC and CBD on common cancer symptoms.
The randomized, placebo-controlled, triple blind study found that, overall, medical marijuana oil extracts “can be meaningfully beneficial for cancer-related symptoms in approximately 50 percent of patients, particularly for sleep and related symptoms.”
The research involved THC-dominant, CBD-dominant and 1:1 oil extracts, as well as a placebo. Notably, it found that the “most helpful extract differed between individuals,” and no single extract type was “routinely better than the others on average.”
There was “no significant preference of one extract over another on average, but a clear preference between extracts for most individuals.”
Regardless of a patient’s primary symptom, about half of participants saw improvements with respect to sleep, anxiety and daytime tiredness. Also, 66 percent of patients expressed a personal preference for an extract with an active cannabinoid as opposed to a placebo.
“Fifty-six percent of the 89 participants with complete Patient Global Impression of Change (PGIC) data reported at least a 1.4-point improvement compared to placebo with at least one extract,” the study authors said. “Subgroup analysis showed response rates of 50 percent for the pain, 47 percent for sleep, and 60 percent for anxiety subgroup.”
“More than half of participants experienced a clinically meaningful benefit over placebo with at least one type of cannabis extract.”
The treatment further found that 2.5 milligrams of THC and CBD extract three times daily was “well-tolerated.” However, “personalization of treatment is required to optimize response.”
“Though it would be convenient to be able to recommend a single agent for everyone, this would clearly not meet the needs of a diverse population,” the study said.
“Our finding that no preparation was better than the others on average, but most participants found one to provide greater benefit individually may further explain why trials that focus on a single preparation may have underestimated the potential benefit of cannabinoids. Restricting patients to a single extract ignores the known heterogeneity in endocannabinoid physiology.”
The study builds upon an expanding body of scientific literature exploring the therapeutic efficacy of cannabis in cancer treatment.
For example, a recent scientific review found that components of marijuana show “consistent and statistically significant anti-tumor effects” in certain types of cancer, including glioblastoma and breast cancer. It also found cannabinoids seem to “enhance chemotherapy efficacy.”
Another systemic review concluded that studies “consistently show” that the CBD is a potential “anticancer agent across different cancer types”—and that effect applies to dogs as well as humans.
A similar analysis showed that CBD “holds substantial promise as an anti-tumor agent” in addition to its other anti-inflammatory properties.
Scientists explored CBD’s effect on many types of cancer—including some of the most aggressive ones, such as glioblastoma, which affects the brain. They also noted it can help suppressing the growth and metastasis of other cancers, including breast, lung, colorectal, ovarian and prostate, among others.
In 2025, a paper published in the journal Pharmacology & Therapeutics, assessed a range of clinical and preclinical findings that the efficacy of chemotherapy drugs can be enhanced by medical marijuana.
In a sign of greater acceptance of medical applications of cannabis, President Donald Trump’s choice to serve as the next White House drug czar has called medical marijuana a “fantastic” treatment option for seriously ill patients and said she doesn’t object to legalization, even if she might not personally agree with the policy.
Also last year, a study found that “patients with cancer using cannabis report significant improvements in cancer-related symptoms.”
