is it normal to feel nothing at all on BPC? week 3

Agree with tendon_theory. What's your diagnosis — actual sacroiliitis, or "SI pain" as a catchall? If it's mechanical/stability, PT for glutes + core is doing more than any peptide will.

3 weeks is early. Push to 6. SI joint stuff is also weird because the "joint" isn't really healing in the same way a tendon does — chronic SI pain is often stability/mechanical rather than tissue damage. BPC may not be the right tool for this goal.

haven't had a real workup tbh. just been calling it SI pain for years. fair point, maybe worth seeing someone before throwing more compounds at it.

"BPC isn't doing anything" is often a sign that the problem isn't what we think it is. Good instinct to pause and diagnose.

been there on SI stuff. ended up being a glute med weakness that PT fixed in 10 weeks, no peptides required. fingers crossed for you.

Yeah honestly SI stuff is frustrating because half the time it's not actually damaged tissue, it's just unstable or your pelvis is tilted weird. I ran BPC for like 4 weeks thinking I had tendinitis in my hip and nothing changed, then got an actual MRI and turns out I just needed to stop sitting like a slob and do some dead bugs. Worth getting imaging done before you waste more time on it.