Oregano oil (carvacrol) — The Antimicrobial Phenol

Carvacrol is a monoterpenic phenol that disrupts bacterial cell membranes, increasing permeability and causing cell death. In mammalian cells, it exerts anti-inflammatory effects by inhibiting the NF-κB pathway and reducing the production of pro-inflammatory cytokines like IL-6 and TNF-α. It also activates Nrf2, upregulating endogenous antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx). Furthermore, recent evidence suggests carvacrol may induce autophagy and mitophagy by transiently dampening mitochondrial membrane potential.

Human trials for longevity are non-existent, but small clinical trials have investigated carvacrol for respiratory conditions. In a randomized, double-blind trial of asthmatic patients, 1.2 mg/kg/day of carvacrol for two months improved pulmonary function tests and reduced inflammatory cytokines. Another trial in patients with sulfur mustard-induced lung injury showed similar improvements in respiratory function and inflammatory markers at the same dose.

In clinical trials for respiratory conditions, carvacrol has been dosed at 1.2 mg/kg/day (roughly 80–100 mg/day for an average adult). For general antimicrobial or SIBO protocols, oregano oil capsules are typically dosed at 100–200 mg, taken 2–3 times daily with meals for short durations (e.g., 2–4 weeks).

Generally recognized as safe in food amounts, but therapeutic doses can cause gastrointestinal upset, heartburn, and allergic reactions. Due to its potent antimicrobial nature, prolonged use may disrupt the beneficial gut microbiome. It should be avoided during pregnancy and lactation due to a lack of safety data.

Key Papers