Understand her cycle.
Be a better partner.
Four Phases is a cycle tracker built for men. Track her four phases. Get daily AI coaching on food, conversation, what to plan, and what to skip. So you show up when it matters.
Founding members get free lifetime access. No card required.
Rest. Comfort. Patience.
She's running on empty. Take things off her plate before she has to ask.
She's coming alive.
Rising energy, optimism, ideas. Match her momentum — don't be the couch.
Peak. Show up. Be present.
The headline window. Plan the date. Put your phone down.
She's narrowing. Be the calm.
Late luteal is where most guys lose. Validate before you fix.
How it works
Set it once. Get guidance every day.
01
One-time setup
Enter her last period and average cycle length. That's it. The math handles the rest.
02
Daily phase brief
Open the app. See where she is today, what's coming, and how she's probably feeling.
03
AI coach
Get one short, in-voice message: what to do today, what to say, what to skip.
Why Four Phases exists
You don't need to read a textbook. You just need the right move today.
Period-tracking apps were built for the person bleeding. Four Phases is the other half — built for the partner who wants to understand what's going on without making it weird. No pink, no flowers, no clinical jargon. Just practical, in-voice guidance: what foods help, what to plan, what to talk about, what to skip this week.
Because being a good partner is mostly about showing up at the right time. Four Phases tells you when, and how.
Private by design
Her health data is nobody's business. Including ours.
Cycle data is some of the most sensitive data that exists, and right now it's being subpoenaed, sold, and leaked across the industry. Four Phases is built so that can't happen here: no account, no cloud database, no analytics, no data broker in the basement. Everything you enter lives on your device and nowhere else.
- Her name never leaves your phone — the AI coach is never told who she is.
- We keep no copy. There is no server-side record of her cycle — nothing to steal, sell, or hand over. (One exception, only if you both opt in: live sync stores her three cycle numbers — dates, no names — deletable by either of you, instantly.)
- One-tap delete. Wipe everything in Settings, instantly, forever — no “contact support to close your account.”
- Never sold, never shared, never used for ads. Not our business model.
FAQ
Does she need to use the app too?+
No. You only need her last period date and average cycle length. Four Phases predicts the rest. You can fine-tune accuracy together if you want, but it's designed to work from your phone alone.
Is this medical advice?+
No. Four Phases is informational — coaching for partners, not a diagnostic tool. Cramps that worry you, irregular cycles, anything concerning — that's a clinician's job, not ours.
Where does her data live?+
On your device. Four Phases v1 uses local storage only — no accounts, no servers storing your data, no tracking. Future versions may offer optional cloud sync; you'll opt in if you want it.
How does the AI coach work?+
The daily brief and Coach chat are powered by Anthropic's Claude. Requests carry only the cycle phase, day number, and any symptoms you logged — never her name or identity. Nothing is stored on our servers; replies are cached on your device.
When does it launch?+
Building in private now. Founding members get early access and free lifetime use. Get on the list and we'll send you a link when it opens up.