How Lulu partner sync works: share your cycle with your partner, privately
In Lulu, open You > Partner and tap "Invite your partner". The share sheet sends a private iCloud link by Messages, WhatsApp or any app. Your partner installs Lulu, picks the partner path in onboarding, opens the link and accepts. They then see your name, cycle day, phase and next period, plus your mood, forecast and fertile window if you turn those on. Never your symptoms, notes or history.
Setting it up, step by step
Partner sync takes about a minute. You start it; your partner joins. Here's exactly what happens.
On your iPhone
- Open Lulu and go to You > Partner.
- Tap Invite your partner.
- The iOS share sheet opens with a private iCloud link. Send it however you like: Messages, WhatsApp, email, or any app on the sheet.
On your partner's iPhone
- Install Lulu from the App Store.
- In onboarding, choose the partner path: "I want to follow my partner's cycle and mood".
- Open the link you sent and accept the invitation.
- That's it. Your status now appears in their Lulu app.
Partner sync is part of Lulu Plus (a 3-day free trial, then a yearly subscription). Your partner doesn't need to track a cycle of their own to follow yours.
What your partner sees, and what they never see
Partner sync shares a small status, not your diary. It's designed so your partner knows enough to be kind, with good timing, and nothing more.
| Your partner sees | Your partner never sees |
|---|---|
| Your name | Your symptoms (cramps, bloating, discharge…) |
| Your cycle day and phase | Your notes |
| When your next period is likely | Your cycle history and past check-ins |
| Your fertile window, only if you turn it on while trying to conceive | Anything else you log for yourself |
| How you're feeling today, if you turn on mood sharing | Your insights and PMS chart |
| Tomorrow's mood forecast with tips, if you turn on mood sharing | Anything you haven't chosen to share |
The tips are small and practical: on a likely low-energy day, your partner might be nudged to handle dinner or suggest a quiet evening. On a good day, it might be a nudge to plan something fun. It's support with timing, not surveillance.
Where the data goes (and where it doesn't)
Lulu has no account and no Lulu server holds your cycle data. Your cycle data stays on your iPhone. When you turn on partner sync, only the small status above is shared through Apple's iCloud, directly between your Apple account and your partner's. Nothing passes through a Lulu server, so we never receive it and couldn't read, sell or hand it over.
- You start it: nobody can follow your cycle without a link you choose to send.
- You can stop any time: stop sharing in You > Partner and your partner's view stops updating.
- One small status: the shared fields are limited by design, so symptoms and notes are never part of it.
Have a quick chat first: "I'm going to share my phase and mood forecast with you. It's not a mood alarm, it's a heads-up. If I'm having a hard day, I'd love a cup of tea more than advice." Setting expectations makes the feature land the way you want.
Why share your cycle with a partner at all?
For many couples the hardest part of PMS or a tough period isn't the symptoms, it's the misunderstanding: "Why are you upset?" "I don't know, I just am." A shared view turns that into "Ah, day 25, she's usually tired. I'll cook." It takes the guesswork, and some of the emotional labor of explaining, off your shoulders.
Partners who want the bigger picture can read our cycle guide for partners and how to support a partner with PMS.
What partner sync is not
If you share it, the fertile window your partner sees is an estimate. Lulu is not contraception and partner sync should never be used to decide when sex is "safe". The mood forecast shows how you usually feel on that cycle day based on your past check-ins; it's a pattern, not a promise, and you're always allowed to feel differently.
If you're in a relationship where you feel pressured to share your cycle, your location or your health information, you never have to. Sharing should always be your choice. If you feel unsafe, talk to someone you trust; in the US you can call the National Domestic Violence Hotline at 1-800-799-7233.
Frequently asked questions
Does my partner need Lulu Plus too?
Partner sync is part of Lulu Plus. Your partner installs Lulu and chooses the partner path in onboarding to follow your cycle.
Can my partner see my symptoms or notes?
No. They see only your name, cycle day, phase and next period, plus today's mood, tomorrow's forecast and your fertile window if you choose to share them (the fertile window only when you're trying to conceive). Symptoms, notes and history stay on your iPhone.
How do I stop sharing with my partner?
Go to You > Partner in Lulu and stop sharing. You can do it any time, and you don't need to tell anyone first.
Does Lulu partner sync work on Android?
Lulu is an iPhone app and partner sync uses Apple's iCloud, so both of you need an iPhone.
Does my cycle data go to Lulu's servers?
No. There's no Lulu account and no Lulu server holds your cycle data. The partner status is shared through Apple's iCloud.
Sources
- Apple Support: Track your period with Cycle Tracking
- Office on Women's Health: Your menstrual cycle
- Office on Women's Health: Premenstrual syndrome (PMS)
This page is for information only and isn’t medical advice. If something worries you, please talk to a doctor.
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