CBG Shows Anti-Inflammatory Promise in Rheumatoid Arthritis

Rheumatoid arthritis has no shortage of targets — TNF-α blockers, interleukin inhibitors, JAK inhibitors. What it lacks is anything that specifically addresses neutrophils, the white blood cells that arrive first at inflamed joints and drive much of the early tissue destruction. A new preclinical study from researchers at the Shanti Center for Medical Cannabis Research at Israel’s Rambam Health Care Campus argues that cannabigerol, the non-intoxicating cannabis compound known as CBG, may be able to fill that gap.

The findings, published March 31, 2026, in the peer-reviewed journal Pharmaceuticals, describe CBG’s effects on isolated human neutrophils and on mice with induced arthritis. The results are preclinical, and the study carries a significant industry-funding caveat — but the mechanism it identifies is specific enough to take seriously as a hypothesis worth testing further.

What the Study Tested

The research team, led by immunologist Igal Louria-Hayon, set up two distinct experimental systems. The first used neutrophils isolated from human blood donors; researchers pre-treated those cells with CBG, then activated them with lipopolysaccharide — a standard method for triggering the same inflammatory cascade that operates in arthritic joints. The second used a mouse model called collagen antibody-induced arthritis, which replicates the acute effector phase of RA.

The human neutrophil experiments were the more methodologically substantial of the two. They involved 13–15 donors for the key cytokine measurements, giving the results a reasonable biological spread for an ex vivo study. By contrast, the signaling pathway experiments — which looked at phosphorylation changes in three key inflammatory proteins — involved only three donors. The authors acknowledged that limitation directly; the data establish a mechanistic proof-of-concept rather than generalizability.

In the ex vivo experiments, CBG reduced TNF-α secretion from activated neutrophils by up to 68 percent and IL-6 by up to 72 percent, both in a dose-dependent pattern. It also blocked the phosphorylation of three intracellular signaling proteins — p38 MAPK, ERK1/2, and Akt — that act upstream of cytokine production. Separately, CBG cut neutrophil migration toward IL-8, a key chemical signal that draws immune cells into joint tissue, by 67 percent.

A separate receptor-blocking experiment produced a more nuanced finding. When researchers selectively blocked the CB2 receptor, CBG’s suppression of IL-6 jumped from roughly 33 percent to about 60 percent — an increase the authors interpret as a functional interaction between CBG activity and the CB2 receptor axis, though they emphasize the mechanism isn’t fully characterized. CBG interacts with multiple molecular targets, including the PPARγ receptor and alpha-2-adrenergic receptors, none of which were tested here.

The Mouse Data and Its Limits

In the mouse model, CBG was administered sublingually — under the tongue — at 35 mg per kilogram of body weight, once daily. Sublingual delivery was chosen partly for its translational relevance, since it avoids first-pass liver metabolism. Mice treated with CBG showed improved arthritis clinical scores and maintained body weight better than untreated arthritic animals. CBG reduced the total number of immune cells flooding the joints by 48 percent, with neutrophil counts dropping to 27 percent of arthritic-control levels and monocytes to 49 percent. Blood levels of IL-6 fell 98 percent; IL-1β dropped 60 percent. In the joint tissue itself, two other inflammatory signals — MCP-1 and IL-1β — declined by 22 and 38 percent, respectively.

The mouse model used here, called CAIA, is well-suited for studying the acute inflammatory phase of RA. It does not capture the full arc of the disease, which involves the long-term breakdown of self-tolerance driven by T and B cell memory. The six-day experimental window reflects that deliberately acute focus. As the authors note, further studies using a chronic arthritis model would be needed before drawing conclusions about long-term disease modification.

One funding disclosure warrants attention. The CBG used in the study was supplied by Raphael Pharmaceutical Inc., which also provided partial funding, and Louria-Hayon holds a provisional patent on CBG applications in RA. The paper states the funder had no role in study design, data collection, or publication decisions — but readers evaluating preclinical evidence should weigh industry involvement alongside the results. That context matters, especially given that the same company reportedly launched a proof-of-concept clinical trial in the United States in 2024 to evaluate CBG in patients with active RA.

Where This Fits in the Evidence

CBG research in rheumatoid arthritis is a small but growing body of literature. A 2023 study in the International Journal of Molecular Sciences examined CBG’s effects on RA synovial fibroblasts and blood mononuclear cells, finding broad anti-inflammatory activity mediated partly through the TRPA1 receptor. The Rambam group compares their findings to that of earlier work, noting that neutrophils appear sensitive to lower concentrations of CBG than the cell types studied previously — a potentially meaningful difference for therapeutic dosing, if the effects hold up in humans.

What distinguishes this study’s framing is the neutrophil-targeting angle. Current RA biologics work indirectly on neutrophils — no approved therapy addresses neutrophil-mediated pathology as a primary mechanism. If CBG’s preclinical effects translate to human disease, it would represent a pharmacologically distinct approach. The fact that CBG does not bind the brain’s CB1 receptor the way THC does removes one obvious concern about cannabis-based candidates in a chronic disease setting. Researchers studying how minor cannabinoids like CBG are synthesized and why their properties differ from better-studied compounds have found that the precursor relationship between CBG and other cannabinoids may explain unexpected anti-inflammatory profiles not seen in THC or CBD.

The Pharmaceuticals paper draws a measured conclusion: further long-term clinical studies are necessary to determine whether CBG’s effects translate across the clinical heterogeneity of human RA. That framing is accurate given where the evidence sits. A six-day mouse model and an ex vivo neutrophil experiment are the opening bid of a research program, not the proof. For patients and clinicians following the science on cannabinoid pharmacology, the study identifies a specific cellular mechanism — and one that a registered clinical trial may soon begin testing under controlled conditions. How that evidence develops will determine whether CBG’s neutrophil story holds up or joins the longer list of preclinical cannabis findings that didn’t survive the translation to clinical trials in inflammatory disease.