Can you take Ozempic or Mounjaro while breastfeeding?
No. Ozempic, Wegovy, Mounjaro, Saxenda and Rybelsus are all not recommended while breastfeeding. The reason is not evidence of harm — it is the absence of evidence altogether. There is no human data on whether these drugs pass into breast milk, though semaglutide and liraglutide were both detected in the milk of lactating animals. Because a risk to a breastfed infant cannot be excluded, every manufacturer advises against use. If you want to both breastfeed and treat obesity or type 2 diabetes, that is a conversation with your prescriber about sequencing, not a closed door.
What every manufacturer says
The position is uniform across the class, and the wording matters.
- Ozempic and Wegovy (semaglutide). Should not be used during breastfeeding.
- Rybelsus (oral semaglutide). Same position.
- Mounjaro (tirzepatide). A risk to the newborn cannot be excluded. A decision must be made whether to discontinue breastfeeding or discontinue the medicine.
- Saxenda (liraglutide). Should not be used during breastfeeding.
Note the framing in the Mounjaro wording, because it is the most honest of the four. It does not say the drug is dangerous. It says the risk cannot be excluded, and that somebody has to choose.
What the animal studies found
Semaglutide was detected in the milk of lactating rats, at concentrations lower than in maternal plasma. Liraglutide was likewise present in rat milk. Tirzepatide has similar findings.
What nobody knows is whether the same happens in humans, at what concentration, and whether an infant absorbs any meaningful amount if it does. These are large peptide molecules, and there is a reasonable pharmacological argument that they would be broken down in an infant gut rather than absorbed. But that is an argument, not a finding. No human lactation study has been done.
Why the data does not exist
It is worth understanding why, because it changes how you read the advice.
Breastfeeding women are excluded from clinical trials almost as a rule. That is not specific to GLP-1s; it applies across most of medicine, and it means the phrase “not recommended in breastfeeding” appears on an enormous number of medicines where nobody has looked rather than where somebody found a problem.
So the guidance here is a default position under uncertainty, not a warning based on observed harm. That does not make it wrong. It does mean the honest answer to “is it dangerous?” is “nobody knows, and the responsible course while nobody knows is not to.”
How the decision usually gets made
In practice the conversation depends heavily on why the medicine is being prescribed.
For type 2 diabetes, there are alternatives with better breastfeeding data. Metformin, for instance, is widely used and considered compatible with breastfeeding. So the usual route is switching rather than stopping treatment altogether, and that switch belongs to your prescriber.
For weight management, the calculation is different, because the treatment is generally deferrable. Most clinicians would suggest waiting until you have finished breastfeeding, given that the medicine is a long-term therapy and a few months makes little difference to the eventual outcome.
Postpartum weight, and the pressure around it
It is worth naming the thing driving a lot of these questions. The pressure to lose weight quickly after giving birth is intense, and it is largely cultural rather than medical.
Breastfeeding itself increases energy requirements substantially, and restricting intake sharply while feeding can affect milk supply. A medicine whose primary action is suppressing appetite is working directly against that. Even setting aside the unknown transfer question, the nutritional argument alone is a reason most clinicians would rather wait.
If your weight is a genuine health concern rather than an appearance one — and it may well be — that is worth raising with your GP now, with a plan for what happens after you finish feeding. Nothing about waiting means doing nothing in the meantime.
When you can start or restart
There is no fixed interval published, because it depends on when you stop breastfeeding rather than on the drug. Once you are no longer feeding, the breastfeeding restriction no longer applies.
What is worth planning is the contraception question, particularly if you may want another pregnancy. Fertility often returns before periods do, and tirzepatide affects the oral contraceptive pill. Ask about both in the same appointment rather than two.
For breastfeeding support in Ireland, your public health nurse, a lactation consultant, or Cuidiú and La Leche League Ireland can all help. For the medicines question specifically, your GP or pharmacist can consult a medicines information service.
Ozempic and breastfeeding: common questions
No. Semaglutide should not be used during breastfeeding. There is no human data on whether it passes into breast milk, though it was detected in the milk of lactating animals, so a risk to the infant cannot be excluded.
Nobody knows. No human lactation study has been done. Semaglutide was detected in the milk of lactating rats at concentrations lower than in maternal plasma, but whether the same occurs in humans, and whether an infant would absorb it, has not been established.
It is not recommended. The manufacturer states that a risk to the newborn cannot be excluded and that a decision must be made whether to stop breastfeeding or stop the medicine. That decision belongs with your prescriber.
There are alternatives with better breastfeeding data, and metformin is widely used and considered compatible. The usual approach is switching treatment rather than stopping altogether. Your prescriber will decide what suits your circumstances.
There is no fixed waiting period tied to the drug. Once you are no longer breastfeeding, the restriction no longer applies. It is worth discussing contraception at the same appointment, since fertility often returns before periods do.
This has not been formally studied, but these medicines work by suppressing appetite, and breastfeeding substantially increases energy requirements. Sharply restricted intake while feeding can affect supply, which is a separate reason most clinicians would suggest waiting.