The Vitamin d regimen is a hand full of different vitamins taken daily to raise you Vitamin D levels in your system to reduce or eliminate cluster headaches and also has other health benefits. It was created by a member on this site Batch who now goes by the name XXX. If you type vitamin D in the search bar you will find all kinds of post with people who are using this to fight clusters. Here is also a link that will take you to information about it.
https://vitamindwiki.com/Cluster+headaches+substantially+reduced+by+10,000+IU+of+Vitamin+D+in+80+percent+of+people
XXX is on this site just about every day and is so helpful to everyone. If you do want to give this a try and have any questions I am sure he would answer them for you.