Now available for iPhone
Test one relationship
in your life.
Correlation Lab turns your Apple Health data into small, focused experiments — one clear question at a time. Pick two things you're curious about, live your life, and get an honest, plain‑English verdict. No dashboards. No noise.
Why Correlation Lab
Most health apps drown you in numbers. This one asks a single question well.
"When X changes, does Y follow?" — that's the kind of insight that actually changes what you do tomorrow morning. Correlation Lab skips the everything-dashboard trap and gives you one clear, testable hypothesis at a time, backed by the data already sitting in your Health app.
One focused question
Pick exactly two metrics — like sleep and focus, or caffeine and rest — and watch how they actually move together, without forty other charts competing for your attention.
Honest, not flashy
Every verdict comes with a confidence level — "Building," "Slight," "Moderate," "Strong" — plus a built-in correlation-isn't-causation reminder. No false certainty, ever.
Look back, or start fresh
Already have years of Health history? Get an instant first read. Trying something new starting today — like cutting evening caffeine? Start a forward-looking experiment that only counts the days you actually live through.
Plain-English, on-device
Summaries are built on-device from your result stats — short, structured, and never uploaded anywhere. Curious for more? Optionally connect your own AI provider, entirely on your terms.
How it works
From curiosity to a clear verdict — in four simple steps.
No setup headaches, no manual spreadsheets. Correlation Lab quietly does the bucketing, the math, and the explaining — you just live your life.
Pick two metrics
Sleep, steps, resting heart rate, HRV, focus minutes, caffeine, readiness, meetings, hydration, and more.
Connect Apple Health
The Lab asks only for what this experiment needs — nothing more — and reads it straight from HealthKit, on-device.
Live for ~2 weeks
Keep doing your thing. The Lab quietly buckets your days and tracks how the two metrics move together.
Get your verdict
A clear, honest answer — stronger, weaker, or no real link — with a confidence level and a "how this was calculated" breakdown.
Private by design
Your health data stays exactly where it belongs — on your phone.
Correlation Lab was built around a simple rule: nothing about your health leaves your device unless you explicitly choose to export it.
- Reads happen locally. All Health data is fetched and analyzed on-device through Apple HealthKit — never uploaded to a server.
- On-device summaries. Plain-English explanations are built locally from your result stats — your raw health data never has to leave to be explained.
- Bring your own model — optionally. Want deeper, multi-experiment analysis? Connect your own AI provider. It's entirely opt-in, entirely under your control.
- Your data, exportable anytime. Download every experiment as CSV, or delete everything from the device with one tap — no questions, no friction.
Go deeper
Correlation Lab Pro unlocks the full lab.
Start free with one focused experiment. When you're ready to run more — or want every Health metric on the table — Pro opens it all up.
- Unlimited experiments
- Every Health metric
- AI-written explanations
- Full lab history
- Side-by-side comparisons
- Blood pressure, sleep phases & more
Lifetime access
One payment · yours forever
Pay once, unlock every Pro feature for good. No subscriptions to remember, no recurring charges — just the full lab, permanently.
Monthly and weekly plans are also available for those who'd rather start small. Restore purchases anytime from the paywall.
Questions
A few things people ask before they start.
Is Correlation Lab a medical device or diagnostic tool?
No. Correlation Lab is a personal exploration tool — it surfaces patterns in your own data, not medical advice or a diagnosis. Every result is shown alongside an honest "correlation isn't causation" reminder. Always talk to a healthcare professional about your health.
How long until I get a result?
Most experiments need at least 14 valid days of data before the Lab will call a verdict — enough to separate a real pattern from noise. If you've already got history in Apple Health, some experiments can give you an instant first read; forward-looking ones build up day by day.
Does any of my health data leave my phone?
No — Health data is read and analyzed entirely on-device via Apple HealthKit, and summaries are built locally from your result stats. Nothing is uploaded unless you explicitly export your own experiments as CSV, or choose to connect your own external AI provider.
What's the difference between "use my history" and "start fresh"?
"Use my history" pulls from your existing Apple Health data, so a long history can sometimes call a verdict right away. "Start fresh" ignores everything before today and only counts days you actually live through — perfect for testing a change you're making starting now, watching the relationship build in real time.
Is Correlation Lab free?
Yes — you can run one focused experiment for free, with the original core metrics. Correlation Lab Pro (available as a lifetime purchase, or monthly/weekly subscriptions) unlocks unlimited experiments, every advanced Health metric, AI explanations, and full history.
Ready when you are
Pick one relationship. Find out what's actually true for you.
Free to start. Honest by design. Private by default.