Origanum vulgare · essential_oil
Evidence tier: insufficient
A powerful antimicrobial used internally for short courses against gut dysbiosis, SIBO, and candida.
Carvacrol and thymol, the two phenolic compounds that give oregano oil its smell and its bite, punch holes in microbial cell membranes, which kills bacteria and fungi. This is well demonstrated in the laboratory and is not in dispute. What is entirely undemonstrated is whether enough intact carvacrol survives digestion and reaches the small intestine at a concentration high enough to do the same thing there, and whether it would spare the beneficial gut bacteria while doing so. It is a real mechanism looking for a human outcome.
Insufficient. There are essentially no human efficacy trials for anything oregano oil is marketed for. The in vitro record is genuinely impressive: carvacrol and thymol rupture microbial membranes, and oregano essential oil kills Candida species and multidrug resistant bacteria in a dish, in some isolates outperforming fluconazole. None of that is a human claim. A compound that kills an organism in a petri dish has cleared the easiest possible bar; the gut is not a petri dish, and the leap from in vitro antimicrobial activity to a clinical outcome in a person is exactly the leap that fails most often. There are NO randomised controlled trials of oregano oil for SIBO. The single study everyone in the supplement trade cites is Chedid 2014, and it does not say what it is quoted as saying: it was a RETROSPECTIVE CHART REVIEW at one clinic, not a randomised trial; patients CHOSE their treatment rather than being randomised; only 37 people took the herbal arm; the herbal arm was a COMMERCIAL MULTI HERB COMBINATION (Dysbiocide plus FC Cidal, or Candibactin AR plus BR) in which oregano oil is one ingredient among many, so nothing in it isolates oregano oil at all; and the headline result (46 percent versus 34 percent breath test normalisation versus rifaximin) was not statistically significant, meaning it demonstrates no difference rather than equivalence. For Candida, the human trial literature amounts to a few small studies totalling under a hundred participants. NCCIH's position is that there is insufficient evidence to support most health claims about oregano oil in humans. That is the honest verdict.
50 to 100 mg standardised extract (70% carvacrol) twice daily with food. Maximum 2 to 4 weeks at a time, then break.
Strong herb, not for long term use. Avoid in pregnancy. Can disrupt beneficial gut bacteria.
Pregnancy: avoid
Breastfeeding: avoid
Active compounds: carvacrol, thymol
Remedies using Oregano Oil · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.