Birth control built around you
An FDA Cleared, non-hormonal, non-invasive way to take control of your fertility.
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What can we help you with?
How it works
Choose a device
Use our free thermometer when you sign up. Or sync our app with your Apple Watch or Oura Ring.
Take your temperature
Use your chosen device to take your temperature right when you wake up.
Open the Natural Cycles app
The app shows you your fertility status, cycle trends, and helpful insights.
How effective are other forms of birth control?
NON-HORMONAL
Natural Cycles°
93%
Copper IUD
99%
Condom
87%
HORMONAL
Hormonal IUD
99%
Vaginal Ring
93%
Contraceptive Pill
93%
Backed by science, the Natural Cycles° algorithm is powered by your body temperature.
Inside the app
Unlock
Our FDA Cleared algorithm uses your temperature to identify fertile and non-fertile days.
Track
Log mood, energy, and more to see how your cycle impacts you.
Learn
Customized insights and expert content to help you understand your unique experience.
Hear directly from Cyclers like you
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#NaturalCycles
![We don’t have any numbers on the birth control effectiveness of these citrus-based contraceptives, but they’re definitely not doctor-recommended today 😅 While it’s possible the natural acidity of a lemon might act as a kind of spermicide and kill off straggling sperm (yes, there are studies on this), the whole thing sounds a bit too… zingy for our taste 😝
Interestingly, there are some methods today, for example the vaginal gel Phexxi, that build on knowledge that acidity can affect the environment in the vagina and make it harder for sperm to swim 🛟 Phexxi isn't suitable for those with a history of UTIs and is 86% effective with typical use.
Clarke GN, et al. Sperm immobilizing properties of lemon juice. Fertil Steril. 2006;85(5):1529–30. Available from: https://doi.org/10.1016/j.fertnstert.2005.10.040
Planned Parenthood. Phexxi [Internet]. n.d. [cited 2025 May 28]. Available from: https://www.plannedparenthood.org/learn/birth-control/spermicide/phexxi](https://scontent-fra3-2.cdninstagram.com/v/t51.82787-15/528683339_18515014390050385_7488002636352320662_n.jpg?stp=dst-jpg_e35_tt6&_nc_cat=104&ccb=1-7&_nc_sid=18de74&_nc_ohc=-n1YmteEAIMQ7kNvwGnNO_C&_nc_oc=Adk3OmaQd-Yt0Ry0X-j8f4fcwp7M4JYqy5A8ddEsePvkHDgAUUTJ5zsjGUkguh4dEnA&_nc_zt=23&_nc_ht=scontent-fra3-2.cdninstagram.com&edm=ANo9K5cEAAAA&_nc_gid=EbXVpYdPC9m_n478QxrhbA&oh=00_AfVoQ9RMRsi8HClPJ5fbxpFr3IiwuCBaoZRyUCbeW26RRQ&oe=68990204)



Common questions
You must be over the age of 18.Does not protect against STIs.
FDA Cleared
Natural Cycles is 93% effective with typical use, 98% effective with perfect use. No method of contraception is 100% effective. Natural Cycles does not guarantee that you cannot get pregnant, it only informs you whether and when you can become pregnant based on the information that you enter into the application.