The Natural Cycles app – a full guide to this non-hormonal contraception

Reviewed: January 4, 2021
A non-hormonal technological approach to contraception

We review the Natural Cycles app to see if this natural contraception is worth the hype.

Technology has come a long way over the years – twenty years ago the idea of being able to have everything you could ever need on one smart device was pretty mind-blowing. 

The Natural Cycles app is a creation that we admit sounds pretty futuristic, but we promise you it does actually exist.  Downloadable through the click of a button – can the Natural Cycles contraception app be too good to be true?

What is the Natural Cycles app?

Natural Cycles contains an algorithm that analyses your temperature (measured using a thermometer) and menstrual cycle data to calculate when you are fertile and when to avoid sex or use other protection on your fertile days. To make the temperature app easy and simple to use, colours are used to represent different days; ‘green days’ will appear as days that are safe to have intercourse, and ‘red days’ warn you that you will not be protected.

This form of contraception could be classified as a method of natural family planning, but we wanted to include it on its own as so many users are interested in hearing reviews and experiences of the app.

How does Natural Cycles work?

During your menstrual cycle your temperature rises and falls slightly, which is due to the change in your body’s hormone levels. The Natural Cycles algorithm analyses your temperature (and optional luteinising hormone (LH) test results) as well as taking fluctuations and cycle irregularities into account to identify ovulation and thereby calculate your red and green days. 

The number of green days will increase as the algorithm gets to know your fertility cycle – it can take around three months of using the Natural Cycles app for the algorithm to become more effective. On red days, you will need to use protection such as condoms or abstain from sex altogether.

Natural Cycles Effectiveness

According to Natural Cycles, the app is said to be 93% effective with normal use, and 98% effective if it is used perfectly as it’s designed.

Does Natural Cycles work?

Whilst this contraception has a high effectiveness when used perfectly there have been multiple claims of users falling pregnant whilst using the Natural Cycles app. But in some studies the contraceptive app has also been found to be comparable to the contraceptive pill in effectiveness.  

How to get started with the Natural Cycles app

This app is so easy to use and can be set up in three simple steps:

  • Measure – you must begin by measuring your temperature at roughly the same time every morning, it’s advised that this is done at least five out of seven days of the week (otherwise it will result in more red days)
  • Enter your data – enter your temperature into the app, along with your period cycle data
  • Learn your fertility – the algorithm in the app will determine your fertility status and will tell you if you are on a ‘red or green’ day

The Natural Cycles thermometer

The Natural Cycles thermometer isn’t a typical thermometer as it is highly specific. It will measure your body temperature within two decimal places, which is required to predict ovulation. The thermometer is used in the morning when you wake up to let you know whether it’s a green day (not fertile) or a red day (fertile). 

How long does Natural Cycles take to work?

Whilst the app is effective immediately, it can take up to three cycles for the algorithm to get to know you and predict your fertile and non fertile windows.

Natural Cycles vs Daysy

Natural Cycles is the only CE marked app intended to be used as contraception (meaning it meets eu health standards) and is cleared by the US FDA.  Daysy is German made and describes itself as a fertility app rather than a birth control app. Working in the same way as Natural Cycles, Daysy has a flat fee of 289 Euros vs. Natural Cycles monthly subscription of £6.99.

Natural Cycles vs. Flo

Working in a similar way to Natural Cycles, Flo is touted as the number one most downloaded health app, with 36 million monthly active users. Flo premium costs £8.99 a month to use which is more expensive than Natural Cycles £6.99 a month.   

Natural Cycles app advantages and disadvantages

Advantages of Natural Cycles

  • It’s a form of natural contraception that allows you to understand your cycle
  • If you want to get pregnant then you are already aware of your most fertile ‘window’ which can help you to conceive more easily
  • It is a non-hormonal contraception method and therefore does not have associated hormonal side effects.

Disadvantages of Natural Cycles

  • It can take several months for the algorithm to gather enough data to effectively predict your fertile and non-fertile days
  • Factors such as illness, lifestyle, stress or travel may make fertility indicators harder to interpret
  • You may forget to take your temperature or input your menstrual cycle data into the app
  • There is a subscription fee, as opposed to alternative contraception methods available in the UK which are free.

Who should use Natural Cycles?

  • Women that are over 18 years old
  • Women unable to use other types of contraception due to medical conditions
  • Women wanting a form of contraception that doesn’t affect their periods
  • Women that are able to (and will remember to) take their temperature every morning
  • Women that are happy to abstain from sex or use other forms of contraception on red days

Who shouldn’t use it?

  • Women constantly traveling to different time zones or that have an irregular sleeping pattern
  • Women who don’t want periods
  • Women that don’t want a form of contraception that needs to be used daily
  • Women wanting immediate protection against pregnancy
  • Women wanting a form of contraception that also offers protection from sexually transmitted infections (STIs).

Click here to take the Natural Cycles quiz and see if their temperature app is the right method for you.

How to stop using the Natural Cycles app

To stop using the app, all you need to do is just stop recording your periods and temperatures. Theoretically Natural Cycles should have no side effects, but if you want to know more about this, check out the reviews on our website to see what other women have experienced.

Where can I get the Natural Cycles app from?

You can start using Natural Cycles for contraception by purchasing a monthly or annual subscription through the app (found on the App Store and Google Play). The annual subscription includes a two decimal basal thermometer, which you will need to be able to use Natural Cycles; but if you happen to have a decimal basal thermometer lying about then you can get started straight away!

If not, whilst waiting for the thermometer to arrive, you can try using Natural Cycles in demo mode to have a play around and get a feel for the app. Before getting started be sure to read the User Manual, which contains all the information you will need to get the most out of Natural Cycles.

How much is Natural Cycles?

An annual membership for Natural Cycles costs £49.99 with a thermometer included, or £6.99 per month with a £10 cost for the thermometer. 

Can you get Natural Cycles on the NHS?

Currently you’re unable to get the Natural Cycles app on the NHS.

Not sure if Natural Cycles is right for you? Check out our guides to alternative contraceptives available such as the copper coil IUD or combined pill.

Natural Cycles reviews

Thousands of women have shared their contraceptive experiences on The Lowdown. If you would like to see how our reviewers have found Natural Cycles, then check out our contraceptive reviews

Click to read more about Natural Cycles or a similar method, Natural Family Planning.

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Reviewed and edited on 04/01/2021 in line with our content policy.

This guide was brought to you by The Lowdown. We are the world’s first contraception review platform, providing real-life experiences from thousands of reviews collected from our community of men and women.

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