Can't revise menstruation data from >3 days prior Your product doesn't allow you to go back to revise menstruation data if it has been 3 days since the entry. This makes it extremely frustrating if you've already logged multiple months of data, and now have to do a factory reset in order for Daysy to accurately track your cycle. I have contacted Daysy about this issue, and have not been given any way to fix this issue without reseting the device and starting its tracking from day 1. I haven't found any cases online of other customers who have been able to resolve this issue either.

Definitely not worth your money This has to be my biggest Amazon purchase regret and I wish I could return it after 4 months of trying. It is so hard to use, hard to remember how to use, the app sucks, and this technology is not nearly as smart as it leads you to believe. You can’t track your period start days unless you remembered to take your temperature that morning and you can’t go back and update information from over 3 previous days so if you forgot to take it your temperature you’re screwed. You have to manually sync the Daysy to the app and the app to the Daysy- this is fairly straightforward but not something you’d expect from a €300 device. The app feels outdated and pales in comparison to competing apps like Flo. I sincerely do not know how this has 5 star reviews on every platform. If it were €20, it’s totally worth the money. Maybeeee €100. But €300 is ridiculous for how cheap it feels, how outdated it is, and how complicated it is. I seriously doubt this was even made by women for women.

When Daysy did an app update they… When Daysy did an app update they didn’t notify any of their customers that they would no longer be able to edit their mensuration period. This meant for me that my cycle was thrown off which took months to get back on track. I have seen a lot of articles that state their research is not accurate and I have lost my trust in them.

Daysy sync is trash This app is horrible. Yes the tracking feature is cool when I can get my Daysy to SYNC! Which is impossible 95% of the time. Yes the blue tooth is on, yes I have reread the instructions 80 times, yes the notifications is on, yes I let the Daysy fall asleep then try to resume syncing. It takes me having to log out of the app entirely and sometimes uninstall then reinstall just to get a reading. And that sync button in the upper right hand corner is completely useless. It does nothing. No one wants to do that in the morning every day because it won’t automatically sync or even manually sync for that matter.

Literally the biggest waste of money on… Literally the biggest waste of money on the entire planet. Doesn't sync with your phone, takes forever to take your temperature and straight up doesn't work. I have reached out to customer support multiple times and they have told me to download beta versions of their app and all different types of solutions and nothing ever works. Absolutely garbage. Don't waste your money.