Caffeine, nicotine and supplement logging
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Circa: Health Intelligence
Put your daily inputs in context.
Circa logs supplements, caffeine and nicotine, then pairs entries with supported Fitbit data to explore sleep trends and correlations. View decay curves, inspect the nights behind an insight or try the demo before connecting. The app is for personal tracking, not diagnosis or treatment.
Free to download · USD store listing
iOS 17.0+ · See the App Store for current pricing and in-app purchases.
YOUR QUESTION. A CLEAR ANSWER.
How can I compare my caffeine log with my sleep trends?
Circa combines your intake log with supported Google Fitbit Air data to show correlations, stimulant decay curves and a model-based sleep forecast.
Get started with Circa.
- Explore demo mode first, or begin by manually logging caffeine, nicotine or supplements with dose and time.
- Connect the supported Google Fitbit Air data source if you want live sleep information alongside your entries.
- Inspect the statistics and nights supporting each correlation, remembering that a relationship does not establish causation.
Here’s what you can do.
Trend insights with supporting statistics
Demo mode before connecting health data
A look inside.
Original screenshots from the App Store.
Good to know.
What do I need for live sleep data?
The listing specifies a Google Fitbit Air and a Google account. Manual logging and demo mode work without connecting one.
Do the correlations prove what caused my sleep result?
No. Correlations and forecasts are tracking insights, not proof of cause or medical findings. Circa does not diagnose or treat conditions.
Where can I download Circa?
The app is available on the Apple App Store. The listing has the current version, regional availability, privacy details, and in-app purchases. App Store ↗
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Store details checked September 16, 2026.