Creatine is a natural component found in human breast milk and supplies about 9% of an infant's daily creatine needs. However, there are currently no high- quality human studies that definitively confirm the safety of creatine supplementation during breastfeeding. Because research on the transfer of supplemental creatine into breast milk and its effects on nursing infants is lacking, healthcare providers generally recommend caution. It is advised to consult a healthcare professional before taking creatine supplements while breastfeeding. The potential risks to infants, such as unknown developmental effects or kidney strain, are not well understood, so many experts suggest avoiding creatine supplementation during lactation unless specifically prescribed or deemed necessary by a doctor.

In summary, while creatine naturally occurs in breast milk, the safety of taking additional creatine supplements during breastfeeding is not yet established, and medical consultation is important before using it.