Interesting points raised so far. To my knowledge, there aren’t any large-scale studies or definitive case reports directly linking chronic constipation to ED, though scattered case anecdotes exist. The pelvic floor connection is probably the most credible-people with chronic constipation often develop dysfunctional pelvic musculature, and there’s solid overlap with folks who have persistent pelvic pain and sexual dysfunction.
From the clinical talks I’ve attended, pelvic floor PTs report men improving both constipation and ED when the hypertonic muscles are addressed, but this evidence is largely observational. Most medical literature still frames the constipation/ED overlap as “comorbidity” rather than causation-meaning, it’s acknowledged they can co-exist but rarely pinned as one causing the other.
Frankly, the research has a lot of catching up to do. If you suspect pelvic floor problems, it’s worth an assessment by someone specialized in this area. Otherwise, don’t expect a lot of clarity in the mainstream urology world just yet.