The libraryGut

Build a Healthier Gut

Gut health

Also called Gut microbiome diversity, Gut microbiome, Gut bacteria, Healthy gut

3 min plan44 min with every studyUpdated Sep 27, 2026

Who it's forA man aged 18 to 45 who wants a healthier, more diverse gut.

When to see a doctor
  • Call 911 now: bleeding from your butt that will not stop, or a lot of blood or clots. Severe belly pain, or vomiting blood.
  • Urgent care or your doctor today: black or dark red poop, or bloody diarrhea. Black, tarry poop: 911 or the ER.
  • Your doctor: diarrhea that lasts more than 7 days, or blood or slime in your poop.
  • Your doctor: belly pain or bloating that keeps coming back, or losing weight without trying.
  • Your doctor: low iron on a blood test, or a parent, brother or sister with bowel cancer or inflammatory bowel disease.
  • Your doctor: gut symptoms for over 4 weeks, for a celiac blood test and a poop test for inflammation.
  • Fermented food brings on headache, a rash or bloating again and again: stop it and see your doctor.

I am not a doctor. This is not medical advice. This is self-education. Every dose on this page is the one a trial or a label used, quoted from it. It is not a prescription. Talk to a physician who has your history before any medicine or supplement. Blood in your poop, black poop, or weight loss without trying: see a doctor first.