I've been taking 800 mg Berberine daily now for about two weeks. For many years I have had pretty bad gastrointestinal problems as part of my POIS symptom set. Those symptoms were reduced a lot a few months back when I started eating an MCAS-friendly diet. But there was still often mucus in my stool. After I started taking Berberine on top of my diet, I noticed changes pretty much immediately. The same day, IIRC. My stool had virtually no mucus in it. It was solid yet not hard or hard to pass. In other words, seemed healthy. Also, my gut generally seems calmer. Less noises and discomfort.
I think it's also helping my prostate a bit. But I'm less certain of that. I've also had a lot of prostate problems as part of my symptom set, most notably trouble peeing, where you feel like you have to go but nothing comes. That seems to have been less pronounced also, after I started with Berberine, but it's too early to be sure of the connection.
I'm definitely gonna keep taking it as I've long suspected my POIS case is deeply linked to my gut, and so far Berberine seems great for my gut.