Dietary Supplement Helps Maintain Normal Blood Vessel Tone* Once Daily 600 mcg Parthenolide Clinical studies have increased interest in the parthenolide in Feverfew for its role in maintaining normal blood vessel tone.* Mygrafew provides the level of parthenolide recommended by both Canadian and British health authorities for optimal results. Each tablet provides the recommended level of 600 mcg parthenolide in a once daily dosage. Clinical potency Mygrafew is standardized to 3% parthenolide. Nature s Way® Mygrafew is free of common food allergens such as yeast, milk, lactose, wheat, sugar, soy or corn.