Is Botox (botulinum toxin) contraindicated in a lactating woman?

Botox is NOT Contraindicated During Breastfeeding

Botulinum toxin can be used during breastfeeding, as its large molecular weight (150,000 daltons) likely prevents passage into breast milk, and limited human evidence shows no harm to breastfed infants. 1

Evidence Supporting Safety

Molecular Weight Considerations

• Medications with molecular weight >800 daltons are unlikely to achieve clinically relevant levels in breast milk 1
• Botulinum toxin's molecular weight of 150,000 daltons makes transfer into breast milk highly improbable 1

Human Case Evidence from CDC Guidelines

The CDC 2021 botulism guidelines document three cases of breastfeeding women with active botulism infection who continued breastfeeding without infant harm:

• Case 1: Mother with severe type A foodborne botulism requiring intubation breastfed her 8-month-old throughout illness; no botulinum toxin detected in breast milk, and infant remained asymptomatic 1
• Case 2: Mother with type A botulism breastfed 2-month-old infant who remained asymptomatic 1
• Case 3: Mother with type B botulism requiring tracheostomy breastfed 2-month-old infant who remained asymptomatic 1

Recent Research on Cosmetic Botox

A 2024 pilot study analyzed breast milk from lactating women after facial botulinum toxin injections (40-92 units) and found that when toxin was detectable, levels were well below the reported lethal oral dose for infants 2

Clinical Recommendations

For Cosmetic/Therapeutic Botox Use

• Breastfeeding does not need to be interrupted after cosmetic or therapeutic botulinum toxin injections 2
• The theoretical risk to the infant is minimal given the local action at injection sites and minimal systemic absorption 3
• Recent evidence (2025) indicates low likelihood of drug transfer into breast milk, particularly for migraine prevention doses 3

For Mothers with Active Botulism Infection

The CDC recommends:

• Continue breastfeeding while monitoring the infant closely for signs of botulism 1
• Monitor infant for cranial nerve findings, weakness, or feeding difficulties 1
• If temporary interruption is chosen (during the 1-2 day delay before antitoxin administration), mother should express and discard milk with lactation specialist support to maintain supply 1

Important Caveats

Context Matters

• The evidence cited from CDC guidelines addresses active botulism infection (systemic toxin exposure), which represents a far more severe exposure than cosmetic/therapeutic injections 1
• If infants remained safe during maternal botulism infection, cosmetic/therapeutic use poses even less theoretical risk 2, 3

Monitoring Parameters

• Watch for infant signs of botulism: poor feeding, weak cry, constipation, hypotonia, or cranial nerve abnormalities 4
• These symptoms are exceedingly unlikely with maternal cosmetic/therapeutic use but represent the theoretical concern 2, 3

Common Pitfall to Avoid

• Do not unnecessarily interrupt breastfeeding based on theoretical concerns when evidence suggests safety 2, 3
• Interruption of breastfeeding carries its own risks: reduced maternal milk supply, potential breast infection, and loss of breastfeeding benefits to infant 1