GLP-1 Medications & Breastfeeding: What Does the Research Actually Say?
GLP-1 medications like Ozempic, Wegovy, Mounjaro and Zepbound have become very common for the treatment of diabetes and weight management. This has also brought up a big question for postpartum moms: Can you use a GLP-1 medication while breastfeeding?
Until recently, the answer was unknown because we had very little to no human lactation data. But new research is beginning to give us more information.
This isn't a recommendation for or against using a GLP-1 medication while breastfeeding. Instead, let's look at what has actually been studied, what researchers have found so far, and what we still don't know.
What Are GLP-1 Medications?
GLP-1 medications work by mimicking hormones involved in blood sugar regulation, digestion and appetite. Some medications act only on the GLP-1 receptor, while others, such as tirzepatide, act on more than one hormone pathway.
Common medications include:
Semaglutide: Ozempic, Wegovy
Tirzepatide: Mounjaro, Zepbound
Liraglutide: Saxenda, Victoza
Because these medications may be used long-term, many women who stop them during pregnancy eventually have questions about whether or when they can restart them postpartum.
Why Has There Been So Much Caution During Breastfeeding?
For a long time, we simply didn't have good human data showing how much of these medications, if any, entered breast milk.
A lack of evidence showing safety is not the same thing as evidence showing that a medication is harmful.
Much of the caution around GLP-1 medications during lactation has been related to this lack of information. Now, we're beginning to see studies specifically looking at their transfer into human milk.
What Do We Know About Semaglutide?
Semaglutide is one of the first GLP-1 medications for which we have published human milk data.
In 2024, researchers published Subcutaneous Semaglutide During Breastfeeding: Infant Safety Regarding Drug Transfer into Human Milk in the journal Nutrients.
The study included 8 breastfeeding mothers taking injectable semaglutide at doses ranging from 0.25 mg to 1 mg per week. Researchers collected breast milk samples immediately before a dose and again at 12 and 24 hours after the dose.
The result?
Semaglutide was not detected in any of the milk samples.
The testing method could detect concentrations as low as 1.7 ng/mL. Because researchers couldn't say the concentration was literally zero, they calculated a theoretical worst-case relative infant dose (RID) assuming semaglutide was present just below the level they could detect. Their maximum projected RID was approximately 1.26%.
For context, an RID below 10% is commonly used as a general screening benchmark suggesting relatively low infant exposure, although that number alone does not establish that a medication is “safe”.
There are also limitations to consider.
The babies in this study were 4–23 months old, were mixed-fed rather than exclusively breastfed, and were exposed to breast milk while their mothers took semaglutide for approximately 3–9 weeks. Mothers reported normal infant growth and development during that period, but this was a very small study and it did not evaluate long-term outcomes.
Another important distinction: this study looked at injectable semaglutide. Oral semaglutide products such as Rybelsus can contain an absorption enhancer called salcaprozate sodium, so the injectable findings shouldn't automatically be applied to oral semaglutide.
The numbers at a glance:
8 mothers
0.25–1 mg/week
24 milk samples collected
0 samples with detectable semaglutide
Detection limit: 1.7 ng/mL
Maximum theoretical RID: ~1.26%
What About Tirzepatide?
We now have human lactation information for tirzepatide as well.
In a manufacturer-sponsored clinical lactation study, 11 healthy lactating women were given one single 5 mg subcutaneous dose of tirzepatide. Researchers collected milk samples over a 28-day period, resulting in 171 breast milk samples.
Tirzepatide was undetectable in 164 of the 171 samples.
That's approximately 96% of all samples collected.
Small amounts were detected in the remaining 7 samples, but the total amount detected across the entire 28-day collection period represented less than 0.02% of the mother's administered dose. The last measurable concentration occurred 5 days after the dose.
The numbers at a glance:
11 lactating women
Single 5 mg dose
171 milk samples
164/171 undetectable (~96%)
7 samples with measurable drug
Total detected: <0.02% of the maternal dose
Last measurable level: 5 days after the dose
Limitations to consider:
This study evaluated a single dose, not the repeated weekly dosing used in real life. Because tirzepatide can accumulate with repeated dosing, LactMed specifically notes that milk concentrations during steady-state use could be higher than those seen after a single dose.
We also now have additional early data from women actually using tirzepatide weekly.
A separate report included 5 breastfeeding women taking 2.5–5 mg of tirzepatide per week. Milk samples were collected around their regular doses. Some samples contained levels below the study's ability to accurately quantify the drug, and none exceeded the quantification limit of 2.38 mcg/L. The mothers continued breastfeeding to varying degrees and reported no adverse effects in their infants attributed to tirzepatide. However, this research remains very small and the report is currently cited by LactMed as a preprint instead of a large peer-reviewed clinical trial.
What About Other GLP-1 Medications?
It’s important not to treat every medication in this category as interchangeable.
We have more human lactation information for some GLP-1 medications than others. Data from semaglutide or tirzepatide can't automatically be applied to medications such as liraglutide or other drugs in the same class.
There's More to Consider Than Milk Transfer
One of the most important things to consider actually has nothing to do with how much medication enters breast milk.
GLP-1 medications can significantly decrease appetite and food intake. During lactation, however, the body has increased energy and nutrient needs to support both milk production and mom’s health. We know that on average, most women need an extra 300-500 additional calories to support milk production.
For a breastfeeding mom taking a GLP-1 medication, it's very important to consider:
Overall calorie intake
Protein intake
Vitamins and minerals
Hydration
Rate of weight loss
Postpartum healing and recovery
Milk production
A medication having very little transfer into breast milk doesn't answer all of the questions surrounding its use during lactation. Adequate nutrition still matters.
How Can You Make Sure You're Eating Enough?
Because GLP-1 medications can significantly reduce hunger and appetite, relying on hunger cues alone may not always be enough, especially while breastfeeding, since your energy and nutrient needs are higher.
If you're using a GLP-1 while breastfeeding, a few strategies may help:
Eat on a schedule. Try not to wait until you're hungry to eat. Regular meals and snacks can make it easier to meet your needs even when your appetite is low.
Prioritize protein. Include a protein source with meals and snacks to support postpartum recovery, muscle mass and overall nutrition.
Choose nutrient-dense foods. When portions are smaller, make those bites count with foods like eggs, Greek yogurt, meat, fish, beans, whole grains, fruits, vegetables, nuts and healthy fats.
Don't forget carbohydrates and fats. Your body needs all 3 macronutrients for adequate nutrition.
Make eating easy. Smoothies, protein shakes, protein bars, yogurt, jerky, overnight oats, sandwiches and other quick options can be helpful when a full meal doesn't sound appealing.
Pay attention to trends. Significant fatigue, weakness, dizziness, very rapid weight loss, difficulty recovering from exercise or a noticeable change in milk production may be reasons to take a closer look at your overall intake.
Ask for individualized guidance. A registered dietitian or other qualified healthcare professional can help estimate your energy and nutrient needs, especially if you're struggling to eat enough.
Breastfeeding mothers generally require additional energy compared with their pre-pregnancy needs, although the exact amount varies based on factors such as activity level, body size and whether breastfeeding is exclusive or partial.
Even with a smaller appetite, your body still needs enough energy and nutrients to support you and lactation.
So, Are GLP-1 Medications Safe While Breastfeeding?
The most accurate answer right now is: we know more than we used to, but there are still unanswered questions.
Early human lactation data for medications such as injectable semaglutide and tirzepatide are reassuring when it comes to the amount of medication reaching breast milk. At the same time, the available studies are still limited, particularly when it comes to long-term infant outcomes and use while breastfeeding very young or exclusively breastfed babies.
Instead of labeling every GLP-1 medication as automatically “safe” or “unsafe” during breastfeeding, the decision should be individualized.
Things to consider include:
The specific medication
Why the medication is being used
The mother's health
Baby's age
Whether baby is exclusively or partially breastfed
Maternal nutrition and rate of weight loss
The evidence available for that particular medication
Questions to Ask Your Healthcare Provider
If you're considering starting or restarting a GLP-1 medication while breastfeeding, some helpful questions include:
Why am I taking this medication, and what are the benefits for my health?
What lactation data are available for this specific medication?
How old is my baby and how much breast milk are they receiving?
Are there concerns about my calorie or nutrient intake?
How quickly am I losing weight?
Should my milk supply or baby's growth be monitored?
Are there alternative medications or approaches worth considering?
Your prescribing provider, baby's Pediatrician, a Registered Dietitian, and Lactation Consultant can work together to help you make a decision based on your individual situation.
