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Peptides and breastfeeding: what LactMed and the labels say

Many women want to lose pregnancy weight while breastfeeding, and GLP-1 drugs are the obvious question. This page sets out what has actually been measured in breast milk, drug by drug, from the National Library of Medicine's LactMed database and the labels themselves.

Last updated November 3, 2026 · Reviewed by Grey Peptides Editorial Board · ✓ Every claim sourced · No products sold, no seller named

📋 Key takeaways

Injected semaglutide: not detected in breast milk in the one study that measured it, LactMed reports; no adverse effects were reported in breastfed infants.14

Tirzepatide: usually undetectable in breast milk, and LactMed says that is not a reason to stop breastfeeding, while advising caution with a newborn or preterm baby.2

Semaglutide tablets are the exception. The absorption enhancer in them (SNAC) is present in human milk, and the labels advise against breastfeeding on the tablets.67

Liraglutide, dulaglutide and the research peptides: nothing has been measured in human milk.3910

On this page

  1. What LactMed says, drug by drug
  2. What was actually measured
  3. What each label says (section 8.2)
  4. Research peptides and breastfeeding
  5. Frequently asked questions
  6. Related on Grey Peptides
  7. Sources

What LactMed says, drug by drug

LactMed is the US National Library of Medicine's peer-reviewed database on drugs and breastfeeding. Each record summarises what has been measured in milk and in breastfed infants, and is revised as studies appear.

  • Semaglutide (record revised August 15, 2026). Not detectable in the milk of mothers injecting it; no adverse effects reported in breastfed infants. LactMed says only the injectable forms are recommended while breastfeeding, because the oral tablets contain salcaprozate sodium (SNAC), which may pass into milk and accumulate in infants. Some experts suggest monitoring the infant's growth and development and the mother's nutrition.1
  • Tirzepatide (record revised August 15, 2026). Usually undetectable in breastmilk at the doses studied; it is probably partly broken down in the infant's gut and poorly absorbed, and LactMed says it is not a reason to discontinue breastfeeding, with caution advised for a newborn or preterm infant.2
  • Liraglutide (record revised May 15, 2026). No information is available on use during breastfeeding. Because it is a large peptide, milk levels are expected to be low and infant absorption unlikely, but LactMed advises caution until more data are available.3

What was actually measured

The semaglutide finding rests on one study: milk from eight women injecting semaglutide, collected at 0, 12 and 24 hours after a dose, held no semaglutide above the method's limit of detection. Using the limit of quantification as a worst case, the authors estimated a maximum relative infant dose of 1.26%, far below the conventional 10% threshold.4 Eight women is a small study (our reasoning).

The tirzepatide figures come from the maker's single-dose study in 11 women, summarised in the label: tirzepatide was undetectable in 164 of 171 milk samples, and the cumulative amount in the remaining 7 was under 0.02% of the mother's dose.8 LactMed notes that a single-dose study does not capture accumulation with weekly use.2

A 2026 systematic review of diabetes drugs in breastfeeding found plasma-to-milk transfer data for only 5 of 20 drugs, semaglutide among them, and that most guideline recommendations were not based on clinical evidence.5

What each label says (section 8.2)

The labels are more cautious than LactMed, because a label speaks only to the data the maker submitted. The sentences below are quoted from each current US label and checked against it at every build.

From the FDA label (quoted word for word from the current US label)

ProductWhat the label saysLabel section
Wegovy (semaglutide)“There are no data on the presence of subcutaneously administered semaglutide or its metabolites in human milk, the effects on the breastfed infant, or the effects on milk production.”section 8.26
Wegovy (semaglutide)“advise patients that breastfeeding is not recommended during treatment with WEGOVY tablets.”section 8.26
Rybelsus tablets (semaglutide)“A clinical lactation study reported semaglutide concentrations below the lower limit of quantification in human breast milk. However, SNAC and/or its metabolites are present in human milk.”section 8.27
Zepbound (tirzepatide)“In a single-dose clinical lactation study, the concentration of tirzepatide in breast milk was found to be either undetectable or low compared to the maternal administered dose”section 8.28
Victoza (liraglutide)“There are no data on the presence of VICTOZA in human milk, the effects on the breastfed infant, or the effects on milk production.”section 8.215
Trulicity (dulaglutide)“There are no data on the presence of dulaglutide in human milk, the effects on the breastfed infant, or the effects on milk production.”section 8.29
Vyleesi (bremelanotide)“There is no information on the presence of bremelanotide or its metabolites in human milk, the effects on the breastfed infant, or the effects on milk production.”section 8.214
Egrifta WR (tesamorelin)“mothers should not breastfeed if they receive EGRIFTA WR.”section 8.212
Forteo (teriparatide)“Avoid FORTEO use in women who are breastfeeding.”section 8.211
Imcivree (setmelanotide)“Treatment with IMCIVREE is not recommended for use while breastfeeding.”section 8.213

Three labels go further than "no data": teriparatide (avoid while breastfeeding), tesamorelin (mothers should not breastfeed, partly because of HIV transmission in the population it treats) and setmelanotide (not recommended).111213 Dulaglutide and bremelanotide report no human milk data at all.914

Research peptides and breastfeeding

No study has measured BPC-157, ipamorelin or CJC-1295 in human milk; our PubMed search for each with lactation or breastfeeding returned no records.10 For a product of uncertain content, the infant is exposed to whatever is in the vial, not only to the named peptide (our reasoning; see the grey-market guide). The pregnancy page covers the same gap before the birth.

Frequently asked questions

Can I breastfeed while injecting semaglutide?

LactMed reports semaglutide was not detectable in the milk of mothers injecting it, and no adverse effects were reported in breastfed infants. The Wegovy label says there are no data for the injection and asks you and your prescriber to weigh the benefits. Discuss it with your prescriber and the baby's doctor.

Why is the semaglutide tablet different?

The tablets contain SNAC, an absorption enhancer. SNAC and its metabolites are present in human milk and infants may clear them more slowly, so the labels advise against breastfeeding on the tablets.

Does tirzepatide get into breast milk?

In the maker's single-dose study it was undetectable in 164 of 171 samples. LactMed says that is not a reason to stop breastfeeding, with caution for newborn or preterm babies.

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Sources

LactMed records are cited by their revision date; labels by their DailyMed set and version, quoted from the cached text; studies by PMID, checked on PubMed. All read November 3, 2026.

  1. Drugs and Lactation Database (LactMed), National Library of Medicine. Semaglutide. Last revision August 15, 2026. Read November 3, 2026. Source
  2. Drugs and Lactation Database (LactMed), National Library of Medicine. Tirzepatide. Last revision August 15, 2026. Read November 3, 2026. Source
  3. Drugs and Lactation Database (LactMed), National Library of Medicine. Liraglutide. Last revision May 15, 2026. Read November 3, 2026. Source
  4. Diab H, Fuquay T, Datta P, et al. Subcutaneous Semaglutide during Breastfeeding: Infant Safety Regarding Drug Transfer into Human Milk. Nutrients 2024;16(17):2886. PMID 39275201. Source
  5. Richardson K, Kiptoo J, Mpora Odongkara B, et al. Maternal-to-Infant Transfer of Medications for Type 2 Diabetes Mellitus Via Breastmilk: A Systematic Review of Available Evidence and Clinical Guidelines. Clin Pharmacol Ther 2026;119(5):1223-1234. PMID 41670332. Source
  6. Wegovy (semaglutide) US prescribing information (Novo Nordisk; DailyMed set ee06186f, version 19, effective June 18, 2026), sections 7, 8 and 12. DailyMed
  7. Rybelsus tablets (semaglutide) US prescribing information (Novo Nordisk; DailyMed set 27f15fac, version 14, effective January 30, 2026), sections 7, 8 and 12. DailyMed
  8. Zepbound (tirzepatide) US prescribing information (Eli Lilly; DailyMed set 487cd7e7, version 40, effective August 28, 2026), sections 7, 8 and 12. DailyMed
  9. Trulicity (dulaglutide) US prescribing information (Eli Lilly; DailyMed set 463050bd, version 62, effective June 16, 2026), sections 7, 8 and 12. DailyMed
  10. PubMed searches run November 3, 2026 through NCBI E-utilities: 'BPC-157 AND (pregnan* OR lactation OR breastfeeding)' 0 records; 'ipamorelin AND (pregnan* OR lactation)' 0; 'CJC-1295 AND (pregnan* OR lactation)' 0. Source
  11. Forteo (teriparatide) US prescribing information (Eli Lilly; DailyMed set aae667c5, version 44, effective August 3, 2026), sections 7, 8 and 12. DailyMed
  12. Egrifta WR (tesamorelin) US prescribing information (Theratechnologies; DailyMed set 839334d3, version 2, effective July 29, 2026), sections 7, 8 and 12. DailyMed
  13. Imcivree (setmelanotide) US prescribing information (Rhythm Pharmaceuticals; DailyMed set 70c3ccf7, version 14, effective April 1, 2026), sections 7, 8 and 12. DailyMed
  14. Vyleesi (bremelanotide) US prescribing information (Cosette Pharmaceuticals; DailyMed set f1d0c1b5, version 1, effective November 13, 2025), sections 7, 8 and 12. DailyMed
  15. Victoza (liraglutide) US prescribing information (Novo Nordisk; DailyMed set 5a9ef4ea, version 31, effective October 14, 2025), sections 7, 8 and 12. DailyMed

This section reports what labels, LactMed and published studies say; it is not medical advice, and it does not replace the obstetrician, midwife, prescriber or pharmacist who knows your history. Grey Peptides sells nothing, links to no seller and rates none. If you are pregnant and have taken something you are unsure of, the MotherToBaby service (1-866-626-6847 in the US) answers questions about exposures in pregnancy and breastfeeding.