I'm not a biochemist, but I like to look at things in detail, so it looks like the same molecule based on my quick look per wikipedia... not aruging that, just trying to understand because putting the molecular structure aside, synthetic form of anything is seldom exactly the same from the real thing, perhaps enviornment surrounding it... how it was made ..etc. would those factors contribute to the purity.. for example there is information that during Pitocin manufacture it has to be purified some way... I suppose I do need to do more research on how it's made to understand the details, though it's not at the top of my list right now.. but I found the topic interesting and thought I'd throw it out there.