botox for migraine

one of my closest friends has been suffering from chronic headaches aka migranes for years. she is totally useless when she has migraine attack. she has tried all the medicines she could and has consulted doctors but nothing has really worked for her just yet. when i read about botox for migraines i immediately sent her the link. i read that botox relieves migraines as it relaxes tight muscles according to some study done. i guess this would still undergo more study. but if it does relieve migraines, it will surely help a lot of people.