Butterbur for Migraines: Why I Changed My Mind About This Herb

I’ll be honest: for years, I was pretty skeptical about butterbur. When patients would ask about it for migraines, I’d usually steer them toward magnesium or riboflavin instead. The whole pyrrolizidine alkaloid (PA) toxicity thing made me nervous, and honestly, the early studies felt a bit... thin.

But then I actually sat down and read through the randomized controlled trials—the good ones, with proper blinding and placebo controls—and I had to eat my words. The data on PA-free butterbur extract for migraine prevention is surprisingly solid. In my practice now, it’s become a go-to recommendation for certain patients, especially those who can’t tolerate standard pharmaceuticals or want a more natural approach.

Here’s the thing, though: you absolutely cannot use just any butterbur product. The PA-free part isn’t optional—it’s critical. I’ve seen too many sketchy supplements on Amazon that claim to be “PA-free” but don’t have the testing to back it up. That drives me crazy, because we’re talking about potential liver toxicity here.

What the Research Actually Shows

Let’s start with the big one: a 2004 randomized, double-blind, placebo-controlled trial published in Neurology (2004;63(12):2240-2244). This was the study that made me reconsider butterbur. Researchers followed 245 patients with frequent migraines for 4 months. The group taking 75 mg of PA-free butterbur extract twice daily saw their migraine frequency drop by 48%—compared to just 26% in the placebo group. That’s a statistically significant difference (p<0.05), and honestly, that’s better than some prescription preventatives.

But here’s where it gets interesting: the dose matters. In that same study, a lower dose (50 mg twice daily) only reduced frequency by 36%. So we’re talking about a pretty specific therapeutic window.

Another trial—this one from 2005 in the European Journal of Neurology (2005;12(9):732-736)—looked at 60 patients over 12 weeks. The butterbur group (again, 75 mg twice daily) had 3.4 fewer migraine attacks per month compared to baseline, versus 1.8 fewer in the placebo group. The effect size here was moderate but meaningful (p=0.02).

Now, I should mention the Cochrane Database systematic review from 2011 (doi: 10.1002/14651858.CD009782). They analyzed two high-quality trials with 293 total participants and concluded that butterbur is “effective” for migraine prevention, with a number needed to treat (NNT) of 9. That means for every 9 people who take it, 1 will achieve at least 50% reduction in migraine frequency who wouldn’t have with placebo. That’s actually pretty good for an herbal intervention.

What’s the mechanism? Well—for the biochemistry nerds—butterbur contains petasin and isopetasin, compounds that seem to inhibit leukotriene synthesis and reduce inflammation in cerebral blood vessels. There’s also some calcium channel blocking activity, similar to some prescription migraine drugs. A 2020 review in Phytotherapy Research (2020;34(10):2496-2509) summarized these mechanisms pretty well.

Dosing, Brands, and What I Actually Recommend

Okay, so the data looks good—but only if you’re using the right product at the right dose. Here’s what I tell patients:

Dose: 75 mg twice daily of standardized PA-free butterbur extract. That’s the dose used in the positive trials. Some people start with 50 mg twice daily for a week to assess tolerance, but the therapeutic dose is 75 mg.

Form: Look for extracts standardized to contain at least 15% petasins. The petasins are thought to be the active compounds.

Brands: This is where I get picky. The brand used in most of the clinical trials is Petadolex® (manufactured by Weber & Weber). They use a specific CO2 extraction process that removes PAs, and they actually publish their safety testing. In my practice, that’s what I recommend. I’ve also seen decent third-party testing on NOW Foods’ Butterbur Extract (PA-free), but honestly, the research is on Petadolex.

What to avoid: Any butterbur product that doesn’t explicitly say “PA-free” or “pyrrolizidine alkaloid-free.” Also avoid teas, tinctures, or raw butterbur root—these almost certainly contain PAs. And I’d skip the generic Amazon brands that claim PA-free status without third-party verification.

Timing: It can take 8-12 weeks to see the full preventive effect. So patients need to be patient—no pun intended.

Who Should Avoid Butterbur

Look, no herb is for everyone. Here’s my contraindication list:

• Pregnancy or breastfeeding: Absolutely not. There’s insufficient safety data, and why risk it?
• Liver disease or elevated liver enzymes: Even PA-free products might stress an already compromised liver.
• Allergy to plants in the Asteraceae family: That includes ragweed, marigolds, daisies—if you’re allergic to these, you might react to butterbur too.
• Children under 18: The studies are in adults. I don’t use it in kids.
• People taking cytochrome P450 3A4 substrates: Butterbur might inhibit this enzyme system, potentially affecting drugs like some statins, calcium channel blockers, or immunosuppressants. When in doubt, check with your pharmacist or me.

Side effects are usually mild—some burping, GI upset, fatigue. But if you develop itching, yellow eyes/skin, or dark urine (signs of liver issues), stop immediately and get liver enzymes checked.

FAQs: What Patients Actually Ask

Q: How long until I see results?
A: Most studies show improvement within 4-8 weeks, but full preventive effects might take 3 months. It’s not an abortive—don’t take it when you have a migraine, take it daily to prevent them.

Q: Can I take it with my prescription migraine meds?
A: Often, yes—but you need to check with your prescriber. Butterbur might allow you to reduce your pharmaceutical dose, but don’t change anything without supervision.

Q: Is it better than magnesium or riboflavin?
A: Different mechanisms. In practice, I often combine them: butterbur plus magnesium glycinate (400 mg daily) plus riboflavin (400 mg daily) can be a powerful natural prevention stack. The data on butterbur might be slightly stronger for frequency reduction.

Q: Why is it so expensive?
A: The PA-removal process adds cost. Cheap butterbur is dangerous butterbur. I’d rather you take a different supplement than risk a non-PA-free product.

Bottom Line: My Take as a Clinician

So here’s where I’ve landed after reviewing the evidence and using this in practice:

• Butterbur works for migraine prevention—the data from multiple RCTs convinces me. The 48% reduction in frequency (vs. placebo) in the best study is clinically meaningful.
• PA-free is non-negotiable. Never use raw butterbur, teas, or untested extracts. The liver toxicity risk is real.
• Dose matters: 75 mg twice daily of standardized extract. Less might not work as well.
• It’s part of a toolkit, not a magic bullet. I combine it with lifestyle changes, stress management, and sometimes other supplements like magnesium.

One last story: I had a patient last year—a 42-year-old teacher with 8-10 migraines monthly. Topiramate made her foggy, propranolol dropped her blood pressure too much. We tried butterbur (Petadolex, 75 mg twice daily) plus magnesium. After 3 months, she was down to 3-4 migraines monthly with fewer side effects. It’s not a cure, but for her, it was a game-changer.

Disclaimer: This is educational information, not medical advice. Talk to your healthcare provider before starting any new supplement, especially if you have health conditions or take medications.