K.A.
I looked it up on Lactmed which I use for reference and it's not even listed. What information I found using Google was all very uncertain about using it because there has been no data to support if it's safe or not. It's been banned by the FDA in certain forms, but they consider it safe in the way it's being used in topical creams. That gives me pause personally.
It's topical which is absorbed into the system less than if you were to be taking it orally.
If it were me I would skip it until I was done breastfeeding since it's only for a cosmetic reason.