Can you use GLP-1 while breastfeeding – what does the research say?

What is GLP-1 and why is it used for weight loss?

GLP-1 is a hormone your body naturally produces in the gut. It helps regulate appetite, fullness and blood sugar levels. Medicines that mimic GLP-1 are used to treat overweight, obesity and type 2 diabetes. Examples include Ozempic, Wegovy and Mounjaro.

By reducing hunger and strengthening feelings of fullness, these treatments can make it easier to eat less and stick to recommended eating habits. For many people, this leads to clear and sustainable weight loss when combined with lifestyle support.

What the research says about GLP-1 and breastfeeding

Right now, there’s very limited scientific evidence on using GLP-1 receptor agonists while breastfeeding. Pregnant and breastfeeding women are rarely included in clinical medicine trials. This also applies to treatments such as semaglutide and tirzepatide.

We don’t currently have enough data to know whether these medicines pass into human breast milk. There’s also a lack of information about any possible effects on a breastfed baby.

When safety evidence is limited, a precautionary approach is taken. That’s why GLP-1 medicines aren’t recommended during breastfeeding.

Possible risks for the baby

GLP-1 medicines affect appetite regulation, stomach emptying and energy balance in the person taking them. For a baby in a period of rapid growth and fully dependent on a steady supply of nutrition, it’s especially important that exposure to medicines through breast milk does not interfere with these processes.

At present, there isn’t enough data to confirm whether GLP-1 receptor agonists pass into breast milk in humans, or how they might affect a baby if they do. Because safety can’t be established, and potential effects on growth or gut function can’t be ruled out, treatment isn’t recommended while breastfeeding.

Why breastfeeding is a particularly sensitive time

Breastfeeding is a unique physiological stage. Your baby receives all or part of their nutrition from your breast milk. Medicines and other substances in your body can pass to your baby through that milk to varying degrees.

A baby’s organs and body systems are still developing. That means they can be more sensitive to substances compared to adults. For this reason, high safety standards apply to any medical treatment during breastfeeding.

If there isn’t enough safety data available, caution is advised. Always speak to a doctor before starting any new treatment while breastfeeding.

How breastfeeding works

The process begins during pregnancy, when hormonal changes prepare the breasts and colostrum is produced. After birth, milk production is stimulated by your baby’s sucking, which triggers hormones such as prolactin and oxytocin.

The first few days can feel challenging. For many parents, it becomes easier once both you and your baby have had time to practise and find your rhythm.

Because your baby’s nutrition during this period comes entirely or partly from breast milk, any medicine used by the breastfeeding person needs to be carefully assessed for safety.

Breastfeeding provides nutrition and comfort during the early months of life. Listening to both your body and your baby’s cues is important.

When could GLP-1 be considered again?

GLP-1 treatment can be considered once breastfeeding has completely stopped. In practice, that means your baby is no longer receiving breast milk at all, even partly.

For many people, treatment can be discussed relatively soon after breastfeeding ends. The decision should always be made together with a doctor and based on your individual situation.

What can you focus on while breastfeeding?

Not using GLP-1 during breastfeeding doesn’t mean putting your health on hold. In fact, this can be a good time to build sustainable habits that support both recovery and long-term wellbeing.

During breastfeeding, it’s usually more helpful to focus on:

• Regular meals with nutritious, varied food
• Enough energy intake to support both milk production and recovery
• Gentle, everyday movement suited to your recovery after birth
• Sleep and rest, as much as realistically possible

Your body goes through significant hormonal changes after pregnancy and during breastfeeding. For many people, weight changes happen gradually over time, but everyone’s experience is different. The goal during this stage isn’t rapid weight loss. It’s creating stable foundations for health and wellbeing.

Once breastfeeding has ended, a new medical assessment can be done and treatment options considered based on your current situation.

Support and resources

There are several established sources of support for breastfeeding in the UK. Your midwife, health visitor or GP can offer guidance and follow-up if you have questions or challenges. There are also specialist breastfeeding services and charities that provide practical help.

It’s common to have questions or periods of uncertainty. Many people need support at different stages. You don’t have to figure it out alone.

Doctors, midwives and dietitians can offer advice on nutrition needs, recovery after pregnancy and questions about medicines while breastfeeding.

Seeking support early can help make your breastfeeding experience feel safer and more sustainable.

Summary

GLP-1 medicines are effective treatments for overweight and obesity, but they aren’t recommended while breastfeeding. The reason is limited scientific evidence and the fact that safety for the breastfed baby can’t be confirmed. A precautionary approach is therefore taken.

Once breastfeeding has fully ended, treatment with Ozempic, Wegovy or Mounjaro may be considered again after an individual medical assessment. This will take into account your health, weight development, any medical conditions and your personal goals.

The aim is always safe, long-term health – for you and your baby.

Frequently asked questions

Can GLP-1 treatment be used while breastfeeding?

No. GLP-1 medicines aren’t recommended during breastfeeding. There isn’t enough data to confirm whether they pass into breast milk or what effects they might have on a breastfed baby.

Because safety can’t be established, a precautionary approach is taken and treatment is not advised during this period.

How does GLP-1 affect appetite and weight?

GLP-1 influences appetite regulation by increasing feelings of fullness and reducing hunger. It also slows stomach emptying, which helps you feel fuller for longer after eating.

This combination often leads to a reduced energy intake. When treatment is combined with lifestyle changes, it can result in clinically meaningful weight loss.

Are there common side effects with GLP-1?

Yes. The most common side effects are related to the digestive system and can include nausea, vomiting, diarrhoea and constipation. These symptoms are often more noticeable at the start of treatment or when the dose is increased, and for many people they improve over time.

Less common but more serious side effects can occur. Contact a doctor if you experience persistent or severe symptoms.

Always discuss any side effects or concerns with your doctor.

Can breastfeeding be combined with weight loss in other ways?

During breastfeeding, the main focus should be supporting recovery and ensuring adequate nutrition for both you and your baby. Active medical weight loss treatment isn’t recommended at this stage.

However, healthy habits can support wellbeing and gradual weight changes over time. This may include nutritious, varied meals, regular eating patterns, appropriate physical activity and sufficient rest.

The goal during breastfeeding is stable health, not rapid weight loss. Once breastfeeding has ended, more structured treatment options can be considered with support from a doctor.

What can help make breastfeeding easier?

Skin-to-skin contact, feeding frequently and ensuring a good, deep latch can all support breastfeeding. Early and regular breast stimulation helps establish and maintain milk production.

Practical guidance from a midwife, health visitor or breastfeeding specialist can be especially helpful in the first few weeks.

Where can I find more information about GLP-1 and breastfeeding?

Speak to your doctor, midwife, health visitor or a breastfeeding specialist service for personalised advice.

Sources

American Journal of Obstetrics and Gynecology. Glucagon-like peptide-1 receptor agonist use in pregnancy: a review.
https://doi.org/10.1016/j.ajog.2024.08.024

Nutrients. Subcutaneous Semaglutide during Breastfeeding: Infant Safety Regarding Drug Transfer into Human Milk.
https://pubmed.ncbi.nlm.nih.gov/39275201/

Frontiers in Endocrinology. Effects of GLP-1 agonists and SGLT2 inhibitors during pregnancy and lactation on offspring outcomes: a systematic review of the evidence.
https://pubmed.ncbi.nlm.nih.gov/37881498/

European Medicines Agency (EMA) – Wegovy (semaglutide)
https://www.ema.europa.eu/en/medicines/human/EPAR/wegovy

European Medicines Agency (EMA) – Mounjaro (tirzepatide)
https://www.ema.europa.eu/en/documents/product-information/mounjaro-epar-product-information_en.pdf

European Medicines Agency (EMA) – Ozempic (semaglutide)
https://www.ema.europa.eu/en/medicines/human/EPAR/ozempic

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