Trialist — Health Experiments

Run simple experiments on yourself, watch your Apple Health data, and find what actually moves your sleep, recovery and energy — all private, all on your iPhone.

Stop guessing whether that supplement, bedtime, or new habit is doing anything. Trialist turns your iPhone into a personal lab: change one thing, and watch what actually happens in your own health data.

HOW IT WORKS

1. Pick something to test — magnesium before bed, an earlier last meal, cold plunges, no late caffeine, a new routine. Anything you can do (or skip) on a given day.
2. Log it in a tap. Trialist reads your Apple Health data in the background.
3. See the difference. Trialist compares your "did it" days against your personal baseline and shows you the change — with the sample size and strength behind every number.

WHAT MOVES YOUR DATA The heart of Trialist is one honest question: what actually moves your sleep, HRV, resting heart rate, steps, or energy? Trialist ranks your habits, doses, and journal tags by their real day-to-day effect — not by hype. Dig into dose-response ("how much is enough?"), timing effects ("does it matter when?"), and change-points ("when did things shift?").

RATE YOUR DAY Give the day a quick 1–10. Over time Trialist learns what separates your great days from your rough ones — and even which way the arrow points (does better sleep make a better day, or the other way around?).

A JOURNAL THAT EXPLAINS THE OUTLIERS Capture what you ate, how you felt, or a gut symptom in a tap, and tag the day (sick, traveling, big meal, hard workout). Trialist lines those entries up against your metrics — so you can catch the food behind a rough night, or the symptom that shows up a day after a trigger.

BUILT ON HONESTY Most health apps overclaim. Trialist does the opposite. Every result shows how much data is behind it (Limited / Good / Strong), calls associations what they are — associations, not proof — and lets you exclude sick or travel days so they don't skew your results.

PRIVATE BY DESIGN

• No account. No sign-up.
• No cloud. Everything stays on your device.
• No third-party tracking or ads.
• Export your full data anytime as JSON, or a clean PDF to share with whoever you choose.

TRACK EVERYTHING IN ONE PLACE

• Binary habits, A/B comparisons (Running vs Cycling), dosed supplements, and timed routines.
• A visual calendar of every trial, streaks, and adherence.
• A day journal with tags to capture context (sick, traveling, big meal, hard workout…).

TRIALIST PRO Trialist is free to start — create experiments, log every day, and see how your "did it" days compare to your baseline. Trialist Pro unlocks the full insight engine: "what moves your data", dose-response ("how much is enough?"), timing effects ("does it matter when?"), change-point detection, head-to-head experiment comparison, food-to-symptom lag, and the good-days analysis. A few free insights each day, so you can try before you commit.

— Trialist is for personal, informational, and educational use only. It is not a medical device and does not diagnose, treat, cure, or prevent any disease or condition. Always consult a qualified health professional before changing your health routine.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/