I absolutely love spicy food, and it’s never affected my gut. I was actually confused when I read about people getting the shits after a curry and wondered if it was a joke. I’ve had curries so hot it caused people to recoil into a coughing and sweating fit after they dipped their finger in and had a taste and I have one every other day. I feel the burning in my mouth, my face turns red, my forehead sweats, my esophagus feels weird, but (tmi I know lol) when I go to the toilet I’m completely fine. no gut pains either.
I felt the same until I had one of those challenge peanut things that add straight up capsaicin crystals. It made my tummy feel not so good when I had it on an empty stomach, but I never had the “spice burns twice” effect until I had malatang and I asked them to do a spice level above their written max level.