Tirzepatide and Breastfeeding

Summary of use during lactation

Tirzepatide is usually undetectable in breastmilk with subcutaneous doses of up to 5 mg. Furthermore, absorption by the infant is unlikely because it is probably partially destroyed in the infant's gastrointestinal tract and poorly absorbed orally. If a mother requires tirzepatide, it is not a reason to discontinue breastfeeding. Until more data become available, tirzepatide should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.

Drug levels in milk and infant serum

Maternal Levels. The manufacturer reports a study of 11 lactating women who were given a single 5 mg subcutaneous dose of tirzepatide. The concentration of tirzepatide in breastmilk was undetectable (<4 mcg/L) in 164 of 171 milk samples. The cumulative amount of tirzepatide detected in the remaining 7 breastmilk samples over the 28-day sampling period was equivalent to less than 0.02% of the maternal administered dose, with the last measurable concentrations occurring 5 days after the dose. This study does not account for accumulation that would occur during typical use, so the amounts in milk at steady-state are probably greater than indicated. Five women who were receiving tirzepatide in doses of 0.5 to 5 mg per week collected milk samples multiple times on the day they received their drug dose, and one woman collected a sample 168 hours after her dose. A few samples found unquantifiable milk levels below the limit of detection of 0.7 mcg/L and no samples exceeded the limit of quantification of 2.38 mcg/L.[1] Infant Levels. Relevant published information was not found as of the revision date.

Effects in breastfed infants

Five women who were receiving tirzepatide in doses of 0.5 to 5 mg per week. All mothers continued breastfeeding to varying extents, but none reported observed adverse effects in their infants attributable to tirzepatide.[1]

Effects on lactation and breastmilk

Relevant published information was not found as of the revision date.

Alternative drugs to consider

Glipizide, Glyburide, Insulin, Metformin, Miglitol

References

1. Diab H, Thompson J, Datta P, et al. Tirzepatide (Zepbound) in human milk during periods of maternal dosing. Preprint submitted to J Chromatogr B 2025. doi:10.2139/ssrn.5387250 PubMed