A new review published in the Chinese Medical Journal provides one of the most detailed examinations to date of how cannabinoids interact with the immune system.

The review outlines how cannabinoids, whether derived from marijuana (phytocannabinoids like THC and CBD), produced naturally in the body (endocannabinoids such as anandamide and 2-AG), or synthesized in laboratories, regulate immune activity through a network known as the endocannabinoid system. The study was conducted by researchers at The Fourth Military Medical University, the Air Force Medical University, and Shanghai Jiao Tong University, all in China.

The study notes that the endocannabinoid system consists of receptors, enzymes, and signaling molecules that influence immune responses, inflammation, and cellular survival. Two main receptors, CB1 and CB2, have been identified: CB1 is found largely in the brain, while CB2 is more closely linked to immune cells.

According to the researchers, cannabinoids can suppress immune activity by inducing immune cell death, slowing proliferation, and reducing the release of proinflammatory molecules like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). In doing so, cannabinoids can help calm overactive immune responses that drive conditions such as multiple sclerosis (MS), rheumatoid arthritis (RA), and inflammatory bowel disease (IBD).

Laboratory studies and early clinical trials have confirmed these effects in several cases, notes the study’s research team. For example, CBD was shown to reduce T-cell activity and inflammation in MS models, while THC and CBD combinations improved muscle stiffness in patients with MS. Similarly, cannabinoids have been observed to lower inflammation and pain markers in RA, and derivatives such as cannabigerol (CBG) reduced oxidative stress in colitis models of IBD.

The review also discusses other conditions where cannabinoids may have therapeutic value. In type 1 diabetes models, CBD reduced inflammatory cytokines and preserved insulin-producing cells. Patients with fibromyalgia have reported improvements in pain, sleep, and memory when treated with CBD or cannabis-based medicines. Meanwhile, cannabinoids also appear to reduce systemic inflammation in sepsis, with endocannabinoid levels serving as possible predictors of patient outcomes. Synthetic cannabinoids and enzyme inhibitors that alter endocannabinoid metabolism are also under development, some of which have shown benefits in preclinical studies of autoimmune and inflammatory diseases.

Despite promising findings, the review stresses that “the use of cannabinoids still poses certain hazards.” The authors note that “the abuse of cannabinoids by pregnant women can exert certain impacts on fetal nervous system development,” and that exposure in utero “may face a greater risk of developing immune dysfunction and infectious diseases.” They also write that common side effects include “dizziness, nausea, dry mouth, tachycardia, and anxiety”. The review also warns that “cannabinoid poses significant risks to mental health,” citing potential links to psychosis, schizophrenia, depression, suicidal ideation, and social anxiety, while noting that these links have not been confirmed.

Adding to the complexity, the review highlights contradictory results in cannabinoid research. For example, while cannabinoids can suppress harmful immune responses in type 1 diabetes, some studies suggest they may also worsen outcomes under certain conditions. Similarly, while THC alleviates intestinal inflammation in IBD, CBD appears to have little effect. The authors stress that these inconsistencies reflect gaps in current knowledge and underscore the need for long-term studies, especially double-blind, placebo-controlled clinical trials.

Ultimately, the researchers conclude that cannabinoids exert powerful immunoregulatory effects with potential to treat a wide range of immune-related conditions. At the same time, “clinical studies validating the safety and efficacy of cannabinoids are still lacking, which limits their application in medicine.”

The full study can be found by clicking here.