How femSense works.

Easy and also completely natural and hormone-free. 

App download

Simply download femSense from the iOS App Store or Google Play Store. Register and start tracking your cycle and symptoms straight away.

Apply patch

The app shows you when to apply your first patch and guides you step by step through the application.

Ovulation recognised!

Use your smartphone to read out your patch twice a day, preferably in the morning and evening, to achieve optimum results.

When you ovulate, your body temperature rises and your measured ovulation is displayed in the app.

Once your ovulation has been confirmed, you can remove your patch.

Voices from our community

The femSense patch is super comfortable to wear and doesn't restrict me in everyday life


Simple installation and uncomplicated reading of the temperature data, a real game changer for me

You need to bear this in mind when wearing your patch
You can do this with the patch
You should not do this with the patch
The patch is a disposable product

Do not wear it for longer than 7 days. If it is reused, the adhesive strength of the patch is no longer guaranteed and skin irritation may occur.

Do not use the patch if you are ill

Elevated temperature and fever can affect your body temperature and therefore the measurement.

In case of itching...

If you experience itching or other discomfort after applying the patch, please remove it.

You have a pacemaker

If you wear a pacemaker, only attach your patch to the side of your body away from your heart, otherwise the smartphone could interact with your pacemaker

Variety is key

Change the side on which you wear the patch with each cycle (unless you have a pacemaker).


Please do not dispose of the patch in normal household waste. You can find more information on this under Recycling in the menu "Product"

System requirements

To be able to use all functions, you need the operating system iOS13 iPhone 7 or higher on iPhones and OS 6.0 Marshmallow or higher with NFC function on Android smartphones.

So sorry. With these medical indicators, femSense cannot reliably determine your ovulation:

Serious, acute or chronic illnesses

  • Nicotine or alcohol abuse
  • Polycystic ovary syndrome (PCOS)
  • BMI > 30
  • Extreme weight fluctuations
  • Allergies to components of skin plasters or adhesives
  • Medication with an influence on body temperature
  • Hormone treatments (e.g. contraceptive pill, hormone injection, hormone coil etc.)

More information on our medical contraindications in our Instructions for use.


Mon - Thu: 08:00 - 15:00
Fri: 08:00 - 12:00 CET

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