The Halcyon app · iPhone
A private diary for what’s changing.
Log symptoms in two taps. Track HRT doses and every change. See patterns over weeks, and walk into appointments with a one-page summary a clinician can read in a minute.
What it does
Two taps
Open, tap the symptom, tap how strong. Done before the sweat dries.
Doses and changes
Patch, gel, pill or spray. Every dose change is dated, so you can see what happened after.
Patterns
Weeks side by side, with sleep, steps and resting heart rate from Apple Health if you allow it.
One page
A summary for your appointment: what, how often, since when, and what you’re taking.
The core idea
What changed after my dose change?
An example, not a promise. Halcyon shows your pattern. What it means, and what to do next, is a conversation with your clinician.
Privacy, in plain words
Where your data lives, and who can see it. The full detail is in our privacy policy.
Your logs are kept in your Halcyon account, on servers in the EU.
That’s why they follow you to a new phone.
Apple Health data stays on your phone.
Sleep, steps and resting heart rate are read on the device, only if you allow it.
Usage analytics are off unless you turn them on.
The switch is in Privacy settings. It never includes your logs, symptoms or treatments.
What it doesn’t do
Halcyon doesn’t diagnose, give medical advice or tell you what to take. It keeps a clear record, so the person who can advise you has something real to work with.