I would suggest the quality of the drug matters far more than the digestive system. And that the difference between first-time experience and hundredth-time (which I don't think is a particularly healthy number of times to hit) is quite large.
So I’ve got a feeling that your point comes from reading some info on the internet, rather than your own experience.
I can't believe I'm saying this on HN, looks like it's finally just another subreddit: I have plenty experience, sure.