Let us be direct where many jewellery sellers are not. The daith piercing’s association with migraine relief is based on an auriculotherapy theory — the idea that the daith area corresponds to an acupuncture point linked to headache relief.
The honest answer: there is no clinical proof. As of the time of writing, no peer-reviewed, controlled study has demonstrated that daith piercings reduce migraine frequency or severity. The reports of relief are anecdotal. The placebo effect may account for some positive reports. Some people experience temporary improvement that fades after a few weeks.
We mention this not to discourage you but to set realistic expectations. If you want a daith piercing for aesthetic reasons and happen to experience migraine benefits, consider it a welcome bonus. But do not abandon prescribed migraine treatment based on a piercing.