I used to belong to one of these forums about migraines because I suffered for over 20 years with debilitation vascular headaches. In 2002, I discovered Feverfew and I have been taking 1,000 milligrams of GNC Feverfew a day since then. I was migraine free for over 4 years.
about a month ago, my migraines came back. I'm a troubleshooter by profession, so I started trying to figure out what changed in my life that caused this. The only thing I could identify was that GNC had changed their Feverfew a few months ago. When that happened, I added one more capsule a day. I didn't bother to do any other calculations on the dosage.
I don't remember what the earlier percentage of Tanacetum parthenium (TP), but I thought it was probably more than the new formulation. I collected data on the percentages and doses of many feverfew suppliers. The new GNC formula was extremely low (0.06%) compared to the higher dose suppliers (0.7%). That's less than 1/10th as much. So, I determined that I would need to take 4 times the previous GNC dosage to equal the typical percentage of TP in some of the higher suppliers.
I switched to the Vitamin Shoppe Feverfew (0.7%) and I now take 4 250mg capsules a day, so I get 7mg of TP per day. My migraines have now subsided and I'm back to a normal life.
I hope this helps someone else with migraines.
(I'm not one who typically trusts herb therapy because I was raised in a medical environment of hospitals and prescription drugs, but I do trust that Feverfew is responsible for eliminating my migraines. One forgets that most medications as late as the Civil War came from plants! Many medications today are simply synthesized versions of herbs that were in use for thousands of years.)