Hey Flip-
For me, when there isn’t clear data about the safety of the use of something while breastfeeding (like in Dr Hales classic book ), then I ask myself …
-would I give this medication to the baby on purpose?
-how important is it to this mom to use this right now?
For the drugs you mentioned:
1)I have happily given BPC to lots of infants for gut healing/feeding issues. Â So no problem there for me.
2)TB4 is a no-go for me. There were some studies of use in open heart surgery in kids under one…. But no long term discussion of how this affected their growth. And really, I don’t want to change tissue regeneration in healthy newborns (things go at the speed they should).
c)CJC/IP:  again, I wouldn’t want to change the growth trajectory of infants.
d)topical cream for scars:  I would have a lot less to worry about with this. But again, I would ask… esp when using something non-mainstream in a nursing mom… “do I need to use it”?  (This is a more CYA thing.  Did you know that you can be sued as late as 2 years after the child turns 18 for perceived malpractice leading to damage in pediatrics.  So this would be 20 years from now. Just to make sure you think about how much you want to use something in a nursing mom).
hope this helps.
cynthia