Mounjaro and contraception: Your guide to staying protected

You’ve sorted your weight loss plan and your contraception, but now you’re wondering if the two are playing nicely together.

As Mounjaro makes its mark on the world of weight loss injections, questions about how it interacts with oral contraceptives (and other birth control methods) are cropping up faster than a surprise period on holiday.

Let’s break down what the evidence says, how to stay protected, and why a little extra knowledge never hurt anyone.

Can you take Mounjaro and contraception together?

Yes — but with a few caveats. While there’s no need to panic and throw your pill packet in the bin, understanding how Mounjaro could potentially affect the effectiveness of some contraceptive methods is key to staying safe, sorted, and stress-free.

Is it safe to take Mounjaro and the pill at the same time?

In most cases, yes. There’s currently no solid clinical evidence suggesting that taking Mounjaro and oral contraceptives at the same time is dangerous [1]. However, because Mounjaro can affect gastric emptying (the way your digestive system moves food and medication along), there’s a risk that it might impact how well your contraceptive pill is absorbed [2].

What official guidance says about Mounjaro and hormonal birth control

The patient information leaflet for Mounjaro notes that slowed gastric emptying could influence how your body absorbs oral contraceptive pills [1]. It doesn’t mean your pill stops working entirely, but it might be less effective, especially in the first four weeks or after a dose increase.

For this reason, healthcare professionals may recommend a non-oral contraceptive method or a backup method for extra protection [3].

What to do if you’re unsure about your current contraception

If you’re on oral contraception and have started taking Mounjaro (or are considering it), the best thing you can do is speak to your healthcare provider. They can offer personalised contraception advice based on your medical history, your weight loss treatment, and how your body responds. When in doubt, double-check, don’t double-dose [4].

What types of contraception can be used with Mounjaro?

Not all contraceptive methods are created equal, especially when there’s a GLP-1 medication in the mix [5]. So, which options are most reliable when taking Mounjaro?

Hormonal contraception (pill, patch, ring, injection, implant)  

• Pill: Effective when taken correctly, but absorption may be affected by Mounjaro’s delayed gastric emptying; consider a backup method.
• Patch: Absorbed through the skin, bypassing the digestive system entirely, less likely to be affected by Mounjaro.
• Ring: Inserted vaginally and delivers hormones locally, another option that avoids the gut.
• Injection: Long-lasting and reliable, and completely avoids any interaction with the digestive system.
• Implant: A low-maintenance option that sits under the skin and steadily releases hormones, no digestive detours here.

Non-hormonal methods (copper IUD, condoms, diaphragms)

• Copper IUD: A hormone-free, long-term method that’s unaffected by any medications you take, including Mounjaro [4].
• Condoms: Easily available, hormone-free, and protect against STIs too — just don’t store them in your wallet next to that coffee loyalty card.
• Diaphragms: A barrier method that’s effective when used correctly, but may be less convenient than other options.

What effect does Mounjaro have on birth control?

It’s the question on every contraceptive-user-turned-Mounjaro-patient’s mind: will my weight loss injection sabotage my birth control? The answer is... not exactly, but the science suggests a little caution doesn’t go astray — especially if your method of choice is oral contraception.

How Mounjaro may affect the absorption of oral contraceptives

Let’s start with the digestive system — the unlikely villain in this drama. Mounjaro, like other GLP-1 weight loss injections, works by slowing gastric emptying. That’s a fancy way of saying your stomach takes its sweet time moving things along, including your oral contraceptives. This delay can potentially interfere with how your body absorbs the hormones in the contraceptive pill, particularly during the first four weeks of treatment or after a dose increase.

So while you might be focused on losing weight, your stomach is focused on... lingering. And when your digestive tract isn’t moving at its usual pace, it’s possible your oral contraception isn’t being absorbed in the way your healthcare provider intended. That’s not to say your pill suddenly becomes useless — but there’s a small risk it might be less effective, which is why backup methods are sometimes suggested during those early weeks.

What the clinical data says

According to the drug label and patient information leaflet for Mounjaro, there may be an effect on the effectiveness of oral contraceptives. The guidance stops short of calling this interaction a dealbreaker, but it does suggest caution, especially during the early stages of your weight loss journey.

We don’t yet have enough safety data to say definitively whether this is a class effect of all GLP-1 medicines, or something more specific to taking Mounjaro. But it’s worth noting that this is not your average multivitamin — it’s a powerful medicine that affects your metabolism, digestion, and hormone signalling. The clinical trials for Mounjaro weren’t designed to test contraceptive failure rates, which means any potential effects on oral contraceptive pills haven’t been fully quantified.

In short? The science isn’t panicking, but it is saying: keep your contraception choices up to date, and don’t ignore the fine print.

Signs your contraception might not be working as expected

Now, we’re not here to fuel fear, but it’s good to know the red flags. If you’re on the contraceptive pill and suddenly experience breakthrough bleeding, breast tenderness, or cycle changes that make your period tracker cry, it’s worth checking in with your healthcare professional.

Likewise, if you’ve had digestive issues like vomiting or diarrhoea around the time of taking your pill, or you’ve noticed an unusual delay in your gastric emptying (hello, never-ending bloat), these could all interfere with your body’s ability to absorb your medication.

And if your goal is effective birth control, it’s best not to rely on luck or TikTok advice. This is where a conversation with your prescribing clinician can be worth its weight in... well, peace of mind.

Do all injectable weight loss treatments stop contraception from working?

Not every GLP-1 medication is guaranteed to mess with your contraceptive pill, but some shared traits are worth keeping in mind.

How Mounjaro compares to other GLP-1 medications

GLP-1 receptor agonists — the class of drugs Mounjaro belongs to — all tend to slow down the digestive system to some extent. That’s how they help with appetite control, blood sugar regulation, and ultimately, weight loss. This class effect means it’s not just Mounjaro raising eyebrows, but potentially other GLP-1 medications too, like Wegovy or Ozempic [2][6].

That said, the prescribing process and official guidance differ slightly between brands, and clinical studies haven’t singled out one as particularly more contraception-interfering than another. But because Mounjaro appears to have a more potent effect on gastric emptying, the concern around oral contraceptives may be slightly more relevant here.

Why the risk is low — but still worth knowing

To be clear: there is no widespread panic in the medical community about Mounjaro and contraception. There are no headlines screaming about unexpected pregnancies caused by delayed gastric transit. But in the world of reproductive healthcare, even a potential dip in contraception effectiveness is enough to warrant some extra precautions.

Your healthcare provider may recommend a non-oral contraceptive method, especially in the first few weeks of treatment or during dose changes. Others may simply advise doubling up with a barrier method — a move that’s more about playing it safe than responding to a proven threat. The risk may be low, but if avoiding pregnancy is a top priority, it’s worth staying one step ahead of your hormones.

Should you use physical contraception as well?

While most people on Mounjaro and contraception won’t need to sound the alarm, there are a few scenarios where adding a barrier method can offer that extra bit of peace of mind, especially in the early stages of treatment when your body’s still adjusting to those weight loss injections.

Conversations to have with your healthcare provider

First things first — don’t play guessing games with your reproductive healthcare. If you’re not sure whether your contraceptive pill is pulling its weight while you’re taking Mounjaro, it’s time to book a chat with your healthcare provider.

The good news? If you’re on the Juniper Programme, you’ve already got a team of experts in your corner — including clinicians who specialise in sexual and reproductive healthcare, weight management, and the art of prescribing powerful medicines safely.

They can offer up-to-date advice tailored to your specific health needs, dose timing, and any other medications you might be on, all while helping you achieve your target weight without sacrificing contraceptive confidence.

Scenarios where backup contraception may be especially important

While every woman’s body is different (and we love that for us), certain situations make the case for a backup method of birth control more compelling. For example:

• You’ve just started oral contraceptives and Mounjaro at the same time (talk about a double whammy for your digestive system)
• You’ve recently had a dose increase and are in that slightly murky four-week adjustment window
• You’re experiencing digestive issues (looking at you, vomiting and diarrhoea) that could interfere with how your oral contraceptive pills are absorbed
• You’re relying solely on oral contraception and want to cover all bases while your body gets used to your new medication

In short, if your gut’s still finding its groove, it may not be the most reliable wingwoman for your contraception. So until your healthcare professional gives the all-clear, consider keeping a condom on standby.

Can you use emergency contraception while on Mounjaro?

We get it — things happen. And if your usual contraceptive pill has let you down (or been forgotten at the bottom of your handbag), you might be wondering whether emergency contraception still works if you’re taking Mounjaro. The short answer? Yes, but with a few important caveats.

Most forms of emergency contraception, including the morning-after pill, can be used safely while on GLP-1 medications like Mounjaro. That said, the effectiveness of oral contraceptives (including emergency ones) may be affected by Mounjaro’s known ability to delay gastric emptying [2]. In plain English: if your stomach’s holding onto things a little longer, that small tablet might not be absorbed fast enough to do its job.

So if you’re within the 72-hour window, and the morning-after pill is your go-to, it’s wise to talk to a healthcare professional about whether a non-oral method, like a copper IUD, may be more effective. Timing, as they say, is everything — especially when it comes to preventing pregnancy.

When to speak to your pharmacist or doctor

If you’ve had a contraception mishap and you’re on weight loss injections, don’t wait around for symptoms to appear or disappear — check in with your pharmacist or doctor right away. They can help you choose the most appropriate emergency contraception, whether that’s an oral option (with guidance around food, other medicines, and timing) or a longer-term solution like the IUD. No judgment. No panic. Just solid, clinical support: exactly what your sexual and reproductive healthcare deserves.

Final thoughts

Much like your weight loss journey, your contraception needs are, well, yours. There’s no one-size-fits-all solution, especially when powerful medicines like Mounjaro are involved. That’s why it’s crucial to personalise your plan with help from a healthcare provider, rather than relying on online forums or influencer hot takes.

When to check in with a health professional for advice

Any time you’re experiencing unexpected side effects, changing doses, or just feeling unsure about whether your oral contraception is still pulling its weight, it’s time to have a word with a healthcare professional. This includes pharmacists, GPs, or (if you’re with Juniper) the expert team behind our Juniper Programme, who can provide up-to-date advice across both weight management and reproductive health.

Reassurance: Most women can use both safely

Here’s the reassuring bit: for most women, using Mounjaro and contraception together is completely safe. With the right support, the right dosing schedule, and maybe the right non-oral method if needed, there’s no reason you can’t lose weight and feel protected at the same time. Your body, your goals, your plan — just with a little clinical guidance sprinkled in.

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