I am 68 years old and had migrains and cluster headaches for years. After numerous Doctors and exams I was desperate. Imitrex worked for me but I was taking up to four shots a day, Tje pill mform was not effective for me. One day I felt a headache coming on and saw a bottle of tums on the shelf. I took a hand full as I did not care at that point. To my surprise I got my vision back and a very small regular headache. All within 15 minutes. Since then I keep a huge bottle of 600mg calcium vitamins every where I go. You can also use the ones thar contain vitamin D, I get them at Walmart for about $5.00 for 250. Very cheap. I take 3 or 4 and it works for me every time. Please try this for yourself and pass this on to others.