Will Taking a GLP-1 Affect My Breast Milk Supply?

I have a question about weight-loss medication and breastfeeding. There seem to have been some new studies that imply it may not be excreted in milk. Is there any more to say about this? I have an eight-month-old and am desperate not to keep gaining weight (hormones make me ravenous) but also don’t want to put her at risk.

—KT

I want to ask you to give yourself some grace. You gestated and birthed an entire human, and now you provide all their nourishment. It is not surprising that you are hungry, and some weight gain (or weight retention) during breastfeeding is extremely typical. There is nothing wrong with considering a GLP-1, but it is worth first talking with your doctor about whether there is any reason for concern.

Let’s assume there are health reasons for you to consider weight-loss medication.

There are two main concerns about breastfeeding on a GLP-1. The first is that the medication might pass through the milk, affecting the baby’s appetite and weight gain. The second is that your milk supply might suffer if you consume fewer calories.

We have new data that suggests the first of these issues may not be a significant concern. A 2024 study of eight women using GLP-1 medications showed no evidence of transfer into breast milk.

The second issue is less easy to evaluate, since individual response to these medications varies, and milk supply reactions will also vary. This concern is more important with a newborn than an older baby, both because milk supply is still getting established and because the baby is not getting calories in other ways. With an eight-month-old, your child is already getting some calories from other sources, and that will be increasingly true.

In the end, there is no significant baby health concern from your starting these medications. It is, however, possible that the medication will affect your milk supply, possibly to the point that you need to change the balance of breast milk and formula. This isn’t bad, but it is a risk to be aware of, depending on your breastfeeding goals.