Migraine Buddy is the most-installed migraine app in the world. It launched in 2015, has roughly 10 million users, and has logged hundreds of millions of attacks. That scale is real and worth respecting — any honest comparison starts by saying so.
Hermly is a different product made for a different user. This page lays out where each one is genuinely better, without the kind of marketing language that makes comparison articles useless. If you’re on Migraine Buddy and considering Hermly, the question to ask is which trade-offs you care about — not which app is “better”.
Where Migraine Buddy is genuinely strong
- Diary depth. Symptom checklists, free-text trigger logs, photo notes, medication tracking with a flexible schedule, and aura drawings. If you want to record every facet of an attack, this is the canonical surface.
- Community-scale weather correlations. With ~10 million users reporting attacks, Migraine Buddy can correlate population-level attack frequency with regional weather patterns. This is unique to scale.
- Doctor report (free tier). Their PDF export has been used in clinical practice for years.
- Android + iOS parity. Migraine Buddy is cross-platform. Hermly is iOS-only.
If those four points match what you’re after, Migraine Buddy is likely the better choice. Stay there.
Where Hermly is genuinely different
- On-device prediction. The migraine forecasting model runs on your iPhone. Your sleep, HRV, cycle, attack records, pain logs, and medications never reach Hermly’s servers. Migraine Buddy’s architecture sends event data to its backend for analysis. Both approaches have legitimate trade-offs; we picked the privacy one. See our privacy promise for the field-by-field detail.
- iOS-native surfaces. Widgets in three sizes, Lock Screen complications, Standby Mode, Dynamic Island Live Activity, Action Button, and an Apple Watch app — see Widgets & Watch. Migraine Buddy has widgets, but they’re a smaller part of the experience.
- Methodology transparency. Our how-it-works page lists the six papers we built on, the AUC numbers from each, and where Hermly sits on the same axis. Migraine Buddy’s prediction methodology is not publicly documented to a comparable depth.
- Calibrated risk number. Hermly outputs a 0–100 probability with a conformal-prediction band, not a community-percentile comparison. The number is a personalised forecast, not a ranking.
Feature-by-feature
| Feature | Migraine Buddy | Hermly |
|---|---|---|
| Attack diary | Deep (symptoms, triggers, photos) | Streamlined (pain, meds, notes) |
| Trigger logging | Manual checklist, broad list | Inferred from HealthKit + cycle + weather |
| Prediction | Population weather correlations | Per-user model, on-device |
| Apple Watch | Complications | App + complications + attack tracker |
| Live Activity / Dynamic Island | Limited | Yes, four regions + action pills |
| Standby Mode | No | Yes, dedicated widget |
| Action Button (iPhone 15 Pro+) | No native intent | Four App Intents |
| Doctor report | Free PDF | Free PDF + structured clinical sections |
| Spouse / partner sharing | No | Yes (Pro, opt-in, read-only) |
| Raw health data sent to servers | Yes | No |
| Platform | iOS + Android | iOS only |
| Pricing | Free + in-app upsells | Free + Pro $49.99/year |
Privacy: the actual difference
The cleanest line between the two apps is where your raw data lives.
In Migraine Buddy, your attack records, triggers, and demographic profile go to Healint’s servers — this is how their community correlations work. Their privacy policy outlines what they collect.
In Hermly, your raw data stays in the iPhone’s App Group sandbox. Even the widget extension and the Apple Watch only see a derived snapshot (risk number, three factors, headline) — never raw HealthKit values. The only thing our servers store is your subscription state, keyed to an anonymous Apple transaction ID. We do not see your email tied to your data.
If community-scale correlations matter to you, Migraine Buddy’s trade-off is honest. If they don’t, Hermly’s is.
Who should pick what
Stick with Migraine Buddy if you: want the deepest attack diary in the category, value community-scale weather correlations, need Android, or already have years of data there.
Try Hermly if you: want predictions that don’t require your data to leave your phone, live on iOS (especially with an Apple Watch), prefer a calibrated risk number over a community-percentile, or want Live Activity / Dynamic Island / Standby Mode integration.
Both choices are defensible. Neither one will diagnose, treat, or prevent a migraine — both are wellness apps that make patterns more visible.