Can I do Cosmelan while breastfeeding?

We do not recommend cosmelan while breastfeeding . There is a possibility of harm to infant. Best to wait till finished with breastfeeding.

Generally we recommend to wait until after breastfeeding for most cosmetic procedures however, this is done at your own risk. Best, Dr. Emer. 

No one has studied this and no one will study this. There is very little chance that something applied topically to your skin would affect your breastfed baby. However, would you want to risk it? That's the ultimate question."This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."