For years I dealt with migraines until I read that it could be due to a lack of zinc in a woman's system when ovulating and menstruating. They said to take calcium, magnesium and zinc. I started taking it daily @ 100% ONLY, and my migraines ceased. If I woke up in the morning, feeling like a migraine might be coming on, I would take 2 and avoid the pain. I told my doctor, he thought I was crazy, but whatever. He then told me that it could be a hormonal migraine and they would cease upon Menopause, so for 10 years I took this. Low and behold, he was right. Now I take it to keep my bones healthy and my body strong against colds and flu. I know this helped with the migraines because I accidentally bought a bottle of 33% and started getting migraines. I asked the pharmacist and he told me I might have built up a tolerance to it. When I bought a new bottle, I realized that it was the wrong strength. So all you people using RX for migraines, give this a try