Quick Answer: Does Mounjaro Affect the Contraceptive Pill?
Yes. Mounjaro is a once weekly injection containing tirzepatide. It can affect how quickly your stomach empties, which may affect the absorption of an oral contraceptive pill.
In June 2025, the UK's MHRA advised people using Mounjaro who rely on an oral contraceptive pill to use an additional non oral contraceptive method, such as condoms, for four weeks after starting treatment and for four weeks after every dose increase.
If you are taking Mounjaro and use the contraceptive pill, this is important to discuss with your prescriber or pharmacist. The advice applies whether you receive Mounjaro privately or through the NHS.
This guide explains the MHRA advice in plain English, when you may need extra contraception, which non oral options may be suitable, and what to consider if your Mounjaro dose changes.
The MHRA Safety Advice, Explained
In guidance published on 5 June 2025, the MHRA advised that tirzepatide may affect the absorption of oral contraceptives because it delays gastric emptying. For people taking Mounjaro who use an oral contraceptive pill, the advice is to use a non oral contraceptive method, such as condoms, or an additional barrier method alongside the pill for four weeks after starting treatment and for four weeks after each dose increase.
The reason for the four week period is that the effect of tirzepatide on gastric emptying can be greater when treatment is started and after the dose is increased. This means extra precautions are particularly important during these periods.
This is UK medicines safety advice, so it is worth taking seriously rather than treating it as a minor detail. If you use the pill and are starting Mounjaro or increasing your dose, speak with your prescriber or pharmacist if you are unsure what contraception you should use.
Why Mounjaro Can Affect Oral Contraceptive Absorption
Mounjaro contains tirzepatide, which acts on GIP and GLP 1 receptors and can slow gastric emptying. This means food and medicines taken by mouth may move through the stomach more slowly.
For most medicines, this may not be a significant concern. However, because the effectiveness of an oral contraceptive depends on its active ingredients being absorbed, the MHRA has issued specific advice for people using Mounjaro and the contraceptive pill.
The effect on gastric emptying can be more noticeable when you first start Mounjaro and after a dose increase. This is why the additional contraception advice applies during those periods.
Does This Apply After Every Dose Increase?
Yes. The MHRA advice applies for four weeks after starting Mounjaro and for four weeks after every dose increase if you rely on an oral contraceptive pill.
For example, if your prescriber increases your Mounjaro dose after several weeks of treatment, you should consider the four week precaution again. It is not only something to think about when you first start treatment.
A simple approach is to discuss your contraception whenever your Mounjaro dose is reviewed. Your prescriber or pharmacist can help you understand which option is appropriate for you and how long you need to use additional protection.
What "Non Oral Contraception" Means and Your Options
Non oral contraception means a method that does not need to be swallowed and absorbed through the digestive system. This means it is not affected by the same changes in gastric emptying associated with Mounjaro. Options include:
- Barrier methods, such as condoms, used alongside your usual pill
- The contraceptive patch
- The vaginal ring
- Long acting methods such as the coil (IUD or IUS), contraceptive implant, or contraceptive injection
The right option depends on your circumstances, preferences, and existing contraception. Your GP, sexual health clinic, or Mounjaro prescriber can help you decide what may be suitable for you. There is no single method that is right for everyone, so the aim is to choose an option that provides appropriate contraception during the period when the effectiveness of an oral contraceptive may be affected.
If you already use a long acting method such as a coil or implant, the specific MHRA advice about reduced oral contraceptive effectiveness does not apply in the same way. This advice is mainly relevant if you rely on an oral contraceptive pill as your primary or only method.
Talking to Your Prescriber About Contraception
Contraception is an important part of a Mounjaro consultation and is nothing to feel awkward about. Your prescriber may ask which contraceptive method you use so they can take this into account when discussing whether Mounjaro is suitable for you.
It is also worth asking about contraception if you are starting Mounjaro or your dose is being increased. This is particularly important if you take an oral contraceptive pill, as you may need to use additional precautions for four weeks after starting treatment and for four weeks after each dose increase.
If contraception has not come up during your consultation, do not worry. You can raise it with your prescriber, GP, or pharmacist and ask what precautions are appropriate for you.
Being clear about the contraception you use allows your healthcare professional to give advice that fits your situation. Someone using a coil or implant, for example, may need different advice from someone who relies only on the combined oral contraceptive pill.
Mounjaro Weight Loss, Pregnancy and Trying to Conceive
Mounjaro is not recommended during pregnancy because there is not enough information to confirm that it is safe for a developing baby. It is also not recommended while trying to conceive or during breastfeeding unless your healthcare professional advises otherwise.
This is separate from the advice about Mounjaro and oral contraceptives, but the two issues are related. If you are using Mounjaro and do not want to become pregnant, it is important to use appropriate contraception throughout treatment and to follow the additional precautions advised for oral contraceptives.
If you are planning a pregnancy, think you may be pregnant, or are breastfeeding, speak with your prescriber before making changes to your treatment.
Stopping Mounjaro: The Wash Out Period
If you are planning to become pregnant, current product guidance recommends stopping Mounjaro at least one month before trying to conceive. This gives the medicine time to leave your body before pregnancy.
The exact advice can differ between GLP 1 medicines because they do not all remain in the body for the same length of time. If you are switching from another GLP 1 medicine to Mounjaro, or planning to switch treatments, tell your prescriber so they can advise you on the appropriate timing.
Do not change your treatment or contraception plan without discussing it with your prescriber.
What to Do If You Think You Might Be Pregnant
If you think you may be pregnant while taking Mounjaro, contact your prescriber or GP as soon as possible. They can advise you on whether you should stop treatment and what to do next.
If you are also experiencing severe vomiting, diarrhoea or signs of dehydration, seek medical advice promptly. These symptoms can sometimes require additional assessment, particularly if they are severe or do not improve.
You do not need to wait for symptoms before contacting a healthcare professional if you think you may be pregnant.
Does This Advice Apply If I Get Mounjaro Through the NHS?
Yes. The safety advice for Mounjaro applies to the medicine itself, regardless of whether you receive it through the NHS or from a private prescriber.
This means the same advice about contraception, pregnancy and dose changes applies whichever prescribing route you use. If you take Mounjaro and use an oral contraceptive pill, speak with your prescriber or pharmacist about the additional precautions recommended after starting treatment and after dose increases.
If you are unsure whether your current contraception is suitable while taking Mounjaro, ask your healthcare professional rather than relying on general advice.
How Long Does Mounjaro Treatment Typically Last?
This is a separate question from the contraception issue, but one worth answering honestly since it comes up often. Mounjaro is generally intended for longer-term use as part of an ongoing weight management or type 2 diabetes treatment plan, rather than a short, fixed course. Treatment usually begins at 2.5 mg for the first four weeks and the dose may then be increased by 2.5 mg every four weeks if tolerated. The maximum maintenance dose is 15 mg per week, depending on what your prescriber decides is appropriate as your maintenance dose. NICE guidance for weight management includes a review point around six months, where your prescriber assesses your response and whether you've lost at least 5% of your starting weight by 6 months before deciding if continuing is appropriate. There's no single fixed treatment duration that applies to everyone, your prescriber will discuss what's realistic for your circumstances as part of ongoing care. Appetite changes can begin within days of the first dose, some people may lose around 1-2 kg by week 4, and visible changes often start to show between weeks 4 and 8. In clinical trials, average weight loss was around 15-21% after 12-18 months, with some users losing up to 22.5% of their body weight after 72 weeks. Mounjaro is not known to be addictive.
Because treatment often continues for many months or longer, the contraception advice covered on this page isn't a one-off consideration to tick off early on. It's something that stays relevant for as long as you're taking Mounjaro and using an oral contraceptive, particularly around any future dose changes your prescriber recommends.
