Norethisterone Product Information
Norethisterone 5mg is a prescription-only period delay tablet containing norethisterone, which is a synthetic progestogen that is similar to the naturally occurring hormone progesterone. It is used to temporarily delay menstruation (period) for up to 17 days, which may be helpful for occasions such as holidays, weddings or sporting events.
Towards the end of each menstrual cycle, progesterone levels naturally drop. This decline signals the womb lining (endometrium) to break down and shed, resulting in a period.
Norethisterone works by maintaining progesterone levels at an artificially raised level, which prevents the womb lining from shedding. As it helps maintain the womb lining, it does not shed until you stop taking the tablets, delaying your period. Once you stop taking norethisterone, progesterone levels fall and your period typically begins within 2 to 3 days.
Take one 5mg norethisterone tablet three times a day (a total of 15mg daily), spacing each dose approximately 8 hours apart. You should start taking the tablets 3 days before you expect your period to begin.
Continue taking the tablets for up to a maximum of 20 days (which delays the period by up to 17 days). Your period should start within 2 to 3 days of taking the last tablet.
Swallow the tablets whole with water. It is recommended to take them at roughly the same times each day to maintain consistent hormone levels. If you miss a dose, take it as soon as you remember. However, if it is close to the time of your next dose, skip the missed dose and continue as normal. Missing a dose may cause a drop in progesterone levels, which could lead to spotting or breakthrough bleeding.
Norethisterone 5mg: Our Pharmacist's Advice
"The most common question we receive about Norethisterone is about timing. To give yourself the best chance of successfully delaying your period, you should start taking the tablets at least 3 days before your expected period date.
It is also important to remember that Norethisterone 5mg is not formulated to be a contraceptive. If you need to prevent pregnancy during the time you are taking it, you should use a barrier contraceptive method such as condoms."
You should start taking Norethisterone tablets three days before you expect your period to start. In total, the tablets should be taken for either a course of 10 total days (to delay your period for 7 days) or 20 total days (to delay your period for 17 days), depending on the length of your treatment.
Starting to take the medication too close to or after the start of menstruation reduces its effectiveness. It is also important to take the treatment consistently, as missing a dose can lead to a drop in hormone levels, which may initiate bleeding or spotting.
If you start norethisterone fewer than 3 days before your period is due, it may not have enough time to raise progesterone levels sufficiently to prevent the womb lining from shedding. In this case, your period may arrive on schedule, or you may experience spotting or irregular bleeding despite taking the tablets.
For the best chance of successfully delaying your period, it is recommended to start the course at least 3 full days before your expected period date.
Norethisterone is designed to be taken before your period begins. If your period has already started, the womb lining has begun to shed, which means norethisterone is no longer reliable at delaying a planned period once bleeding has begun. For this reason, it is important to start the course 3 days before your expected period date rather than waiting until bleeding begins.
If you experience unexpected bleeding or spotting whilst taking norethisterone, this does not necessarily mean the treatment has failed. Light spotting can occur in some cases. However, if the bleeding is heavy or persistent, speak to your prescriber.
If you forget to take a dose of Norethisterone, take it as soon as you remember and then continue taking the remaining doses at the usual times. Do not take a double dose to make up for a missed tablet.
Norethisterone 5mg for period delay is a prescription-only medicine (POM) and cannot be purchased over the counter in the UK.
At Pharmica, we provide Norethisterone to eligible patients after completing our quick online consultation to determine the suitability of the treatment.
Norethisterone FAQs
Your period will normally begin within 2 to 3 days of taking your last norethisterone tablet. After that, your cycle often settles back to its usual pattern, although temporary irregularity can happen.
The period that follows a course of norethisterone is usually similar in length and heaviness to your normal period. Most people find that bleeding lasts between 3 and 7 days, in line with their typical cycle. Some people report that their first period after norethisterone is slightly heavier or lighter than usual, but this should return to normal with subsequent cycles.
If you experience breakthrough bleeding or spotting whilst taking norethisterone, there are a few possible reasons. You may have started the course too late (fewer than 3 days before your expected period), missed a dose, or not taken the tablets at evenly spaced intervals. In some cases, light spotting can occur even when the medication is taken correctly.
If the bleeding is heavy or continuous, contact your prescriber for advice. Do not increase the dose beyond one 5mg tablet three times a day unless specifically instructed by your doctor.
Although norethisterone is a progestogen (the same class of hormone used in some contraceptive pills), the 5mg dose used for period delay is not licensed to be used as a contraceptive, which means it will not prevent pregnancy.
Norethisterone may cause a temporary shift in your cycle timing, as your next period will be calculated from the date you stop taking the tablets rather than from your original expected date. However, it does not permanently change or reset your menstrual cycle. Most people find that their regular cycle pattern resumes within one to two months of completing the course.
Weight gain is not a commonly reported side effect of norethisterone when used as a short-term period delay treatment. Some people may experience temporary bloating or water retention during the course, which can give the impression of weight gain. This typically resolves once the tablets are stopped and your period returns.
There is no known interaction between norethisterone and alcohol, and drinking in moderation is unlikely to affect how the medication works. However, excessive alcohol consumption may contribute to nausea or headaches, which are also common side effects of norethisterone.
Norethisterone tablets should be stored at temperatures below 25°C in the original package to protect from light and moisture. They should also be kept in a cool, dry and dark place to protect them from light. Do not take Norethisterone if you notice any signs of discolouration on the tablets.
If you need to stop taking Norethisterone, do not dispose of the tablets via wastewater or household waste. Instead, speak to a pharmacist for advice on how to properly dispose of any unused tablets.
Norethisterone 5mg Overview
What are the side effects of Norethisterone?
As you would not be taking the tablets for an extended amount of time, side effects are limited. However, if there are some, the following are common: rashes, itching, dizziness, headaches, nausea, and breast tenderness.
Information Leaflet
Always read the patient information leaflet before commencing treatment.
Written and reviewed by our qualified team
Content last updated:
30 Apr 2026