I am the same as you! Occasional diarrhea before Covid but was never constipated. Post Covid, constipated every single day for 8 months now. Colonoscopy was normal. I have also found that a magnesium pill morning and night is the only thing that fixes it, but if I skip even one day it’s back. Doctors won’t believe me that it’s COVID related. I know nothing about Peptiva though, and since the magnesium, is working for me I’m sticking with that. I’ve had a lot of other long COVID symptoms too (severe widespread pain and inflammation, heart palpitations, and chest jumping at night), but the constipation is the only one that’s not improving at all.