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Psilocybin reduces cluster headache attack frequency up to 50%
(www.sciencedirect.com)
10 mg/70 kg, 3 doses, 5 days apart each
That is a fairly mild dose. It's enough for many people to catch a buzz, but it's not going to send them on a tour of a neighboring universe.
It's good to see a study on moderate/low dose applications, actually. The stress relief alone is probably great for a ton of other conditions, now that I think about it.