Stim Check

Most people underestimate how long caffeine stays in their system.

PreFix: Stim Check helps you track your caffeine intake throughout the day and shows how much is still active in your body—so you can make better decisions about timing, performance, and sleep.

Log your coffee, pre-workout, or energy drinks and see a real-time view of your caffeine levels based on your body weight and caffeine half-life.

Features:

Track caffeine intake (coffee, pre-workout, energy drinks)
Visualize your caffeine curve throughout the day
See how much caffeine is still active in your system
Get a “clear by” time for when levels drop below a sleep-safe threshold
Simple, fast, and easy to use

This is a lightweight tool designed for athletes, gym-goers, and anyone who wants better control over their caffeine habits.

Note: This app is currently in public beta. We’d love your feedback.