What the packet says

What is Noristerat?

Hormonal ingredients

What's it made of?

Noristerat is a white sterile liquid. Each dose contains the hormone norethisterone which is a progestogen, in a solution that contains benzyl benzoate and castor oil.

How Noristerat works

The contraceptive injection contains progestogen and is injected into your body every 2 to 3 months. It works to prevent pregnancy in three ways – by stopping ovulation, making the fluid in your cervix thicker (which makes it more difficult for sperm to enter the womb), and preventing the lining of your womb thickening enough for a fertilised egg to implant in it.

Noristerat side effects


  • During intercourse
  • Daily
  • Monthly
  • 1 - 3 Months
  • 1 - 3 Years
  • 3 - 5 Years
  • Permanent
  • Similar to

    Typical effectiveness

    Around 96% effective

    Contains hormones


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    Detailed information

    How to get started

    • Your doctor or nurse will do some tests to make sure that you can have the injection. They check your medical history, make sure that you’re not pregnant and take your blood pressure.
    • You can have the injection at any time in your period cycle. If you have it within the first five days of your cycle, you will be protected from pregnancy straight away. Any other time in your cycle and you’ll need to use condoms or other contraception for seven days.
    • You can have the injection straight after giving birth, or after having an abortion or miscarriage. If you’re breastfeeding, the injection will usually be given six weeks after giving birth.
    • You will be given the injection as you would a standard jab – Depo-Provera and Noristerat are injected into a muscle, usually in your buttocks.
      • Depo-Provera can also sometimes be given in the arm.
      • Noristerat is a thicker solution so you may find the injection is slightly more painful when it’s given.
      • Sayana Press is injected beneath the skin at the front of the thigh or abdomen. It’s possible for you to be taught how to inject Sayana Press yourself at home but not all GPs and clinics currently offer this.
    • The injection can’t be removed from your body, so if you have any side effects you have to be prepared for them to continue during the eight or 13-week period, and for some time afterwards
    • After the injection has been given you only need to go back to your doctor or nurse if you have any problems or when you need a new injection. If you are using the Sayana Press (which you inject yourself at home) you only have to go back to the clinic annually because you will be given a years supply. 

    How to stop

    • A word of caution about the injection – it can take several months and even a year for the hormones to to leave your system and for your fertility to return to normal.
    • To stop, all you need to do is not have your next injection – if you don’t want to get pregnant then you should use another method of contraception from the day that your injection would’ve been due.
    • Check out our survey results to see how long it took most women’s cycles to return to their definition of ‘normal’ after their injections, and learn about after effects they’ve experienced.

    Things that can go wrong

    • One of the main risks with the injection is it can cause thinning of the bones because it affects your natural estrogen levels – however guidance around this can be contradictory and inconclusive. The NHS advises that bone thinning isn’t normally a problem for most injection-users as the bone replaces itself when you stop the injection and it doesn’t appear to cause any long-term problems. Thinning of the bones may be more of a problem if you already have risk factors for osteoporosis – if this is the case your doctor or nurse will probably advise you against the injection.
    • In very rare cases you can have an allergic reaction to the injection. There is also a small risk of a reaction at the spot the injection is given, which may cause irritation, swelling or a scar.
    • Some medicines and antibiotics (like rifampicin and rifabutin, St John’s wort and anti-epilepsy drugs) make the injection less effective. Always tell your doctor or pharmacist that you’re using this contraceptive if you’re prescribed any medication. You’ll need to use condoms or additional contraception until you’re protected from pregnancy again.
    • With any combined type of hormonal contraception there is a slightly increased risk of developing blood clots in your veins and arteries. We are developing a full guide to the medical research on the serious and potentially life threatening side effects of contraceptives here.