Alyx tracks coffee, tea, energy drinks, and other caffeine, then estimates how much may remain in your body later. It gives the habit a timeline instead of treating each drink as an isolated number.
The estimates are not a medical measurement. They are useful for noticing patterns, especially when an afternoon coffee and a restless night feel too far apart to connect.
See the day and week at a glance
The dashboard shows today's intake, weekly averages, the estimated caffeine-free time, and a bedtime forecast. A 12-hour decline view helps explain why a drink can still matter long after its immediate effect fades.
Use the trend rather than one dramatic day. A week of similar afternoon intake is more useful evidence than one late coffee followed by one poor night.
Log a drink with fewer taps
Quick logging matters because an incomplete caffeine record gives a misleading forecast. Alyx supports common drinks and amounts, and the compact panel lets you record an espresso without opening a long form.
Amounts still vary by bean, serving size, and preparation. When the exact value is unknown, consistency is more useful than false precision. Use the same reasonable estimate for the same regular drink.
Compare intake with sleep
Sleep correlations put caffeine and rest in the same view. The app can use Apple Health for private health data and sync through iCloud. This makes longer patterns easier to inspect without manually copying sleep duration into a second tracker.
Correlation does not prove that caffeine caused a bad night. Stress, illness, alcohol, exercise, and schedule changes can all affect sleep. Use the view to form a small experiment, such as moving the last coffee earlier for a week.
What to know before you try Alyx
Alyx is free on iPhone, with optional paid features in the Caffeine Club. Its listing says health data is stored through Apple Health and synced with iCloud.
Caffeine clearance varies between people and can change with medication, pregnancy, health conditions, and other factors. Treat Alyx's curve as an estimate based on the information it has. It should not be used to make a medical decision or to explain persistent sleep problems by itself.
Privacy controls are important because the app connects intake with health and sleep records. Review its Apple Health permissions and share only the categories needed for the comparison you want. You can change those permissions later in the Health app.
Choose it if you want to test a habit rather than ban coffee. Log your usual intake for seven days before changing anything. The baseline will make the next week's comparison more useful.
Keep the drink names and serving sizes consistent during that first comparison.