Combining CBD with cannabigerol (CBG) — a non-psychoactive cannabinoid — reduced the CBD dose needed for seizure protection by over 50% in mice, with both compounds showing low toxicity at therapeutic doses.
Epilepsy researchers developing combination cannabinoid therapies, neurologists treating refractory epilepsy, pharmacologists studying cannabinoid interactions.
What the researchers found
Current antiseizure therapy fails for about 30% of epilepsy patients. Previous research had shown that adding small amounts of THC made CBD much more potent against seizures, but THC's psychoactive effects make it unsuitable for routine epilepsy treatment. This study tested whether CBG — a non-psychoactive cannabinoid — could provide the same potentiation.
In the maximal electroshock seizure (MES) model in mice, researchers generated dose-response curves for CBD alone, CBG alone, and a 1:1 combination. The results were clear: CBG has its own antiseizure properties, and combining it with CBD reduced the effective dose of CBD (ED50) by over 50%.
However, the combination also reduced the toxic dose (TD50) by about 40%, indicating increased toxicity alongside increased potency. The overall therapeutic index (the gap between effective and toxic doses) was narrowed but both drugs showed little toxicity at therapeutic doses.
The interaction between CBD and CBG appeared additive rather than synergistic — meaning the effects were roughly what you'd predict from adding each drug's contribution together, rather than a multiplication effect. This is the first study to provide detailed dose-response data for CBG alone and in combination with CBD for seizures.
Why it matters
Finding a non-psychoactive potentiator for CBD's anti-seizure effects could be clinically transformative. If CBG allows CBD doses to be halved while maintaining seizure protection, patients could potentially achieve the same benefit with fewer side effects (since many CBD side effects are dose-dependent). This is especially relevant for pediatric epilepsy patients where minimizing drug burden is a priority.
The numbers in context
CBD ED50 reduced by >50% when combined with CBG (1:1 ratio). TD50 reduced by ~40%. CBG demonstrated independent antiseizure activity. Both compounds showed little toxicity at therapeutic doses. Current antiseizure therapy effective in only ~70% of patients.
How the study worked
Animal study in mice using the maximal electroshock seizure (MES) model. CBD and CBG administered intraperitoneally, alone and in 1:1 combination. Full dose-response and dose-toxicity curves generated for each compound and the combination. ED50 and TD50 calculated to determine therapeutic indices.
Who was studied
Mice used in the maximal electroshock seizure model.
What this study cannot tell us
Animal model — the MES model is a standard seizure screening tool but doesn't capture all epilepsy types. Only a 1:1 CBD:CBG ratio was tested; other ratios may produce different potency and toxicity profiles. Intraperitoneal injection doesn't model oral drug delivery. The 40% reduction in TD50 (increased toxicity) partially offsets the potency gain and needs careful evaluation. Mouse pharmacokinetics differ from human.
How to read the evidence
Preclinical animal study with rigorous dose-response methodology — provides strong pharmacological evidence for the CBD-CBG interaction but clinical translation requires human trials.
When this study was published
Published in 2026, providing the first detailed dose-response data for cannabigerol as an antiseizure agent and CBD potentiator.
The bigger picture
This is the final piece in the epilepsy cluster in this database, connecting to CBD's clinical epilepsy evidence (RTHC-00160, RTHC-00165, RTHC-00186, RTHC-00189, RTHC-00190) and the computational modeling of CBD's seizure mechanisms (RTHC-00238). The hemp neuroprotection review (RTHC-00271) noted that non-cannabinoid compounds may contribute to therapeutic effects — CBG represents another cannabinoid class that could expand the epilepsy treatment toolkit beyond CBD alone. The 'entourage effect' concept gets concrete evidence here: CBD works better for seizures when combined with another cannabinoid.
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- Would lower CBD:CBG ratios maintain the potency benefit while reducing the toxicity increase? Does CBG potentiate CBD in other epilepsy models beyond MES? Could a CBD/CBG combination product receive regulatory approval for treatment-resistant epilepsy?
Read the original research
Antiseizure Effects of Cannabidiol in Combination With Cannabigerol in the Maximal Electroshock Seizure Model.
Basic & clinical pharmacology & toxicology, 138(2), e70194
Basic & Clinical Pharmacology & Toxicology is a reputable journal focusing on pharmacology and toxicology research.
Citation
Zhou, Han Zhong; Scott, Brian Wayne; Oleksak, Yagoda Izabela; Burnham, Willets McIntyre. (2026). Antiseizure Effects of Cannabidiol in Combination With Cannabigerol in the Maximal Electroshock Seizure Model.. Basic & clinical pharmacology & toxicology, 138(2), e70194. https://doi.org/10.1111/bcpt.70194
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