Yohaku 余白

Perimenopause · symptoms · patterns

Perimenopause has patterns. Yours.

Log symptoms and everyday factors in seconds — Yohaku finds what's connected, right on your phone. No account, no cloud, no ads.

Become a tester Coming soon to Google Play

The free core stays free — forever. Before launch we're inviting a small group of testers: one email, no sign-up.

No account No ads or trackers Works fully offline Free core, forever 16 languages

Your data. Your patterns.

Most apps compare you to other users. Yohaku looks for statistical links between your factors and your symptoms — including next-day effects — and is honest about uncertainty: it says how sure it is, or that it isn't sure yet.

If a pattern stops showing up in your data, it says that too. All analysis runs on your phone.

Today · Tue, 14 Jul

Hot flashes ••• Sleep 5.5 h Coffee ×2
Pattern found

On days after less sleep, hot flashes were stronger — seen on 12 of 16 such days.

Built for perimenopause — not pregnancy

No fertility push, no baby banners, nothing that assumes you want to conceive.

  • 31 preset symptoms — plus any you type yourself, first-class in the analysis.
  • Irregular, short, stop-and-go cycles are facts, not errors. Works fully with no periods at all.
  • A stage estimate with its reasoning spelled out — an orientation point for a doctor's visit, not a diagnosis.

Your symptoms

Hot flashes Brain fog Joint aches Irritability tinnitus — yours + add your own
Stage estimate

Likely late transition — cycle length varied by 9+ days twice in the last 10 cycles.

Private by design, not by promise

There is no server database — we couldn't look at your records if we wanted to. By default the app sends nothing to the internet. Export your data to a file any time; it's yours.

The optional AI features are off by default and ask for separate consent — with a button that shows the exact content before anything is sent. Read the privacy policy — it's written to be read, in 16 languages.

Show what will be sent

anonymised summaries you pick, item by item
daily numbers, last 14 days
your notes
your name
Default

AI is off. Nothing leaves your phone until you say so.

What's inside

Diary in secondsSymptoms with intensity, notes, editing past days.
Everyday factorsSleep, stress, caffeine, alcohol, sugar, spicy food, exercise.
Patterns & insightsHonest statistics on your own data.
Cycle & historyA calendar that accepts irregularity; a year at a glance.
PDF for your doctorSymptoms, cycle and patterns — generated on the phone.
Export & importYour data as a file, any time.
Gentle remindersLocal, no server involved.
Dark theme & large typeReadable at 3 a.m.
16 languagesIncluding the analysis texts — not just buttons.

Free means free

The core — logging, patterns, stage estimate, cycle, notes, the doctor report — is free and stays free. No nag popups, no countdown discounts, no features quietly moving behind a paywall. The optional premium adds AI analysis and an AI chat about your data: a normal store subscription, cancelled in two taps.

Questions you'd probably ask

Where is my data stored, exactly?

In a local database on your phone, in the app's protected storage. No account, no server copy. Before switching phones, use export — it saves everything to a file you control.

Is it really free?

Yes — the entire core is free and self-sufficient. The subscription only adds the AI features, which need a cloud model to run. Nothing from the free core ever moves behind the paywall.

I don't have periods any more. Is Yohaku still for me?

Yes. The cycle is an optional layer, not a requirement. After a hysterectomy, with an IUD or on hormonal contraception, everything else works fully.

What exactly does the AI see?

Nothing, unless you subscribe and separately consent. Even then — only anonymised summaries you select item by item, with a "Show what will be sent" preview. Notes and your name are never sent. Details in the privacy policy.

When can I get it — and what does testing involve?

Yohaku is heading into closed testing on Google Play before launch. Testers install the app the normal way and simply use it for a couple of weeks. Email us for an invite — no sign-up, no obligations.

Is this medical advice?

No. Yohaku is not a medical device and doesn't diagnose. It helps you observe, and gives you something concrete to bring to a clinician.

Yohaku is not a medical device, does not make diagnoses and does not replace professional medical advice. Detected patterns and the stage estimate are aids for self-observation and for a conversation with a clinician.