Butterbur

Supplements · Cardiovascular & Anti-Inflammatory Herbs · Supplement, Typed Supps

A migraine-prevention herb where using the right, PA-free version is a matter of liver safety, not just quality.

Stage by stage

Intake (Extract capsule, PA-free only): Must be processed to remove pyrrolizidine alkaloids (PAs), naturally occurring liver-toxic compounds in the raw plant.
Small intestine (Absorbed): Active compounds absorbed once PAs have been properly removed.
Bloodstream (Circulates): Circulates throughout the body.
Migraine-related pathways (Studied outcome): Studied specifically for migraine prevention, with a genuinely solid evidence base for the properly processed, PA-free extract.

What the evidence supports

Preventing migraine attacks — moderate evidence. Randomised trials of a specific PA-free extract at 75 mg twice daily reduced migraine frequency versus placebo; the American Academy of Neurology once rated it favourably but later withdrew that support over manufacturing-safety concerns, not lack of efficacy.
Easing allergic rhinitis (hay fever) symptoms — limited evidence. Some randomised trials suggest benefit, but higher-quality evidence is lacking.
Evidence that it causes Liver injury from products containing pyrrolizidine alkaloids — strong evidence. Unpurified butterbur contains pyrrolizidine alkaloids that are established liver toxins and potential carcinogens; a large share of commercial products have tested positive for them. This is the defining safety issue of the herb, not a footnote.

Typical dose

Migraine trials used 50–75 mg of a PA-free extract twice daily (100–150 mg/day)

Upper limit: No established UL; use only certified PA-free preparations

Timing

With food, standard dosing — only PA-free labeled products.

Time to effect

Wks–mo: Consistent use for any reported migraine-frequency effect in studies.

Common myth

“Any butterbur supplement is fine as long as it’s natural.” In reality: Unprocessed butterbur contains pyrrolizidine alkaloids that can cause serious liver damage — only products specifically labeled PA-free should ever be considered.