Stim Check

Stim Check helps you track your caffeine intake throughout the day and visualize how much stimulant is still active in your body so you can make better decisions about timing, athletic performance, and sleep. Stim Check is a lightweight, focused utility aimed at athletes, gym-goers, shift workers, students, and anyone who uses coffee, pre-workout mixes, or energy drinks and wants a clearer handle on when stimulant levels will peak and decline. The app is currently in public beta and welcomes feedback from people who want precise, easy-to-read feedback about cumulative caffeine exposure.

Key features and interaction mechanics

The core interaction of Stim Check centers on quick logging and an immediate visual response. Tap to add a drink, select from common beverage types or enter a custom caffeine amount, and the app updates a real-time caffeine curve that shows how intake accumulates and decays. Controls are intentionally simple: large buttons for fast entries between sets or during a commute, an editable quantity field for nonstandard drinks, and a timeline scrub to inspect past or projected levels. Behind that simplicity sits a calculation that uses your body weight and an adjustable caffeine half-life estimate to convert logged milligrams into a dynamic, minute-by-minute estimate of active stimulant in your system.

Progression, history and habit formation

Rather than gamified levels, Stim Check supports habit improvement through clear history and summary views. The app stores day-by-day intake so you can compare mornings, afternoons, and evenings across a week or month. Progression is measured by how your timing changes: fewer late-day peaks, earlier clear-by times, or reduced total daily milligrams. Session summaries show total intake, highest single-dose events, and the estimated time when levels fall below a user-defined sleep-safe threshold. These summaries help you refine routines and plan training or rest days with predictable stimulant effects.

Visual style, timeline structure and data navigation

Visual design emphasizes a single, uncluttered caffeine curve that is easy to read at a glance. The timeline is structured by day with zoom options for hourly or multi-day views so you can inspect both individual events and patterns across weeks. Color and opacity convey intensity without distraction: darker tones indicate higher estimated stimulant concentration, and a clear-by line marks the projected safe period for sleep. The interface supports quick scrubbing to see exact values and timestamps and shows overlapping entries when you log multiple drinks in a short span.

Customization and user controls

Customization in Stim Check keeps the app flexible for different physiology and preferences. You can adjust the caffeine half-life estimate to match how your body typically processes stimulants, switch between metric and imperial units for body weight, and set a sleep-safe threshold that aligns with your sensitivity. Custom drink presets let you save favorite combinations (for example, your go-to pre-workout or a regular coffee order) for one-tap entry. Notifications are optional: enable gentle reminders to log a drink or a clear-by alert to help you wind down before bedtime.

Replay value, challenge systems and behavior nudges

Replay value comes from daily use and the insight that builds over time: logging consistently reveals how timing affects sleep and training quality. Stim Check uses noncompetitive challenge-style prompts rather than game points: try a week with no stimulants after 2 p.m., or aim to shift your clear-by time earlier by an hour across several days. These small, optional challenges are designed as behavioral nudges to encourage experimentation and personal optimization without pressure or artificial rewards.

User experience, accessibility and offline use

The user experience favors speed and clarity, with high-contrast visuals, scalable text sizes, and touch targets sized for one-handed use at the gym. Basic operations work offline because all calculations and stored logs are local to your device; you can add entries and view your recent curve without a network connection. Accessibility considerations include text labels for key controls and compatibility with screen readers; adjustable fonts and a colorblind-friendly palette help make the app usable for a wide range of people.

Limitations, accuracy and beta status

Stim Check provides estimated, not clinical, readings: calculations are based on population averages and your inputs, and results should not be treated as medical advice. The app is focused solely on stimulant (caffeine) tracking and does not replace professional healthcare guidance or track broader nutrition metrics. As a public beta, some features may evolve, and the development team appreciates user reports and suggestions to improve accuracy, usability, and accessibility.

Getting started

Begin by entering your weight and a typical half-life estimate, add your first drink, and watch the caffeine curve update. Over a few days of logging, Stim Check will help you spot late-day intake that disrupts sleep and optimize pre-workout timing for predictable effects. If you value clearer control over stimulant timing and want a simple tool to visualize cumulative intake, Stim Check offers a focused, low-friction way to make informed choices about caffeine use.