Laurie, You asked how natural vs the synthetic oxytocin can be different.
The reason is that if even one atom is in a different place, some molecules
with the same chemical composition will act in different ways.  This is the
kind of erroneous thinking that  so many health food store folks are
susceptble to , and how  unscrupulous 'nutritionists' can hoodwink the
public.
This gives me a chance to say I really appreciate the great 'media watch'
job you do for your group and the wider audience here on Lactnet.  Thanks!
Michelle Scott, RD,MA,IBCLC  in NH