Condition

Epilepsy

Epilepsy is a neurological condition in which bursts of abnormal electrical activity in the brain cause recurrent seizures, and it ranges from mild to severe. Among supplements, the evidence is strongest for cannabidiol (CBD), and large trials in drug-resistant epilepsy, including Lennox-Gastaut syndrome, found people had fewer seizures. Vitamin D has moderate support, but the CBD findings come from specific hard-to-control forms of epilepsy, and most other supplements have only limited research behind them.

Sources: PMID 40217555; PMID 29768152

Supplements studied: 5
Graded outcomes: 2
Trials: 5
People studied: 3,805

Evidence by supplement

Strong
Moderate
Limited
Very limited

5 supplements

Cannabidiol (CBD)

Cannabidiol (CBD): outcomes studied for Epilepsy
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Seizure Frequency Large Improvement	Improves (the measure goes down)	Large effect	4 studies	1,829 people
Studies that measured seizure frequency Effect of Cannabidiol on Drop Seizures in the Lennox-Gastaut SyndromeN Engl J Med · PMID 29768152 Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trialLancet Neurol · PMID 26724101 Cannabidiol as a new treatment for drug-resistant epilepsy in tuberous sclerosis complexEpilepsia · PMID 27696387 and 1 more on the Cannabidiol (CBD) page

Manganese

Manganese: outcomes studied for Epilepsy
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Seizure Frequency Small Decrease	Improves (the measure goes down)	Small effect		80 people

Phenylpiracetam

Cognition: improves

Phenylpiracetam: outcomes studied for Epilepsy
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Cognition	Improves (the measure goes up)		2 studies	40 people
Studies that measured cognition The efficacy of phenotropil in the complex treatment of epilepsyZh Nevrol Psikhiatr Im S S Korsakova · PMID 18646385 Phenotropil in the treatment of vascular encephalopathyZh Nevrol Psikhiatr Im S S Korsakova · PMID 16608112

Folic Acid (Vitamin B9)

Seizure Frequency: changes; see studies

Folic Acid (Vitamin B9): outcomes studied for Epilepsy
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Seizure Frequency	Changes; see studies		1 study	75 people
Studies that measured seizure frequency Vitamins for epilepsy.Cochrane Database Syst Rev · PMID 15846704

Black seed

Seizure Frequency: changes; see studies

Black seed: outcomes studied for Epilepsy
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Seizure Frequency	Changes; see studies		1 study	22 people
Studies that measured seizure frequency The effect of thymoquinone on intractable pediatric seizures (pilot study)Epilepsy Res · PMID 21112742

Key findings

Seizure FrequencyCannabidiol (CBD)Improves (the measure goes down)

The Epilepsy Adjunctive Support protocol

2 primary supplements · 6 supporting supplements

Cannabidiol (CBD)Epidiolex: 2.5–20 mg/kg/day (prescription); OTC CBD: varies widely in quality
Vitamin D2,000–4,000 IU daily (higher if deficient)

See the full protocol

Studies cited

2 studies from PubMed

Efficacy and Safety of Dietary Therapies for Childhood Drug-Resistant Epilepsy: A Systematic Review and Network Meta-analysis.JAMA Pediatr · PMID 36716045
Ketogenic diets for drug-resistant epilepsy.Cochrane Database Syst Rev · PMID 32588435