Built for the daily reality of MCAS
Living with mast cell activation syndrome means tracking a lot of moving parts — foods, environments, medications, weather, sleep — and being taken seriously by clinicians who often don't know the condition. Tether turns your everyday notes into a structured record that helps you spot your own patterns and walk into appointments prepared.
Your data stays on your device. No third-party analytics. No ads.
What you can do
Log flares Free
Severity, affected body systems, onset, duration, suspected triggers, and notes — all in a single calm sheet.
Track foods & triggers Free
Mark safe foods, flag suspected triggers, and capture environmental exposures with autocomplete from your own history.
Medication log Free
Log doses, time taken, and rate how helpful each medication was during a flare.
30-day flare calendar Free
See the last month at a glance with a color-coded heatmap by severity.
Daily check-in reminders Free
A single, gentle nudge per day. No streaks, no guilt.
Emergency info Free
Store an emergency contact and anaphylaxis medications, ready when you need them most.
Trigger correlation Premium
On-device analysis surfaces your most likely triggers based on what you ate or were exposed to in the hours before a flare.
Pattern dashboard Premium
Frequency charts, time-of-day heatmaps, and medication effectiveness comparisons.
Doctor-ready PDF Premium
Generate a structured report your clinician will actually read. Share it from Tether in one tap.
Food label scanner Premium
Point your camera at an ingredient list and Tether warns you about anything on your trigger list.
Weather & pollen Premium
See how the air around you correlates with your flare days.
Apple Health sync Premium
Pull in heart rate, HRV, sleep, and steps to round out the picture.
Pricing
Tether's core logging features are free forever. Advanced insights, the PDF report, and the food label scanner are part of Tether Premium, an optional in-app subscription.
Premium features require a separate in-app purchase. Subscriptions auto-renew unless cancelled at least 24 hours before the end of the current period. Manage or cancel in your App Store account settings at any time.
Get Tether
Tether is available on the App Store for iPhone (iOS 17 or later).
Tether is a personal health tracking tool. It is not a medical device and does not provide medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical concerns.