Oil of Oregano for High Cholesterol (Dyslipidemia)

Oil of oregano has not been shown to lower cholesterol. Only three small trials have tested oregano on blood fats, they used three different preparations, and they disagree.

Two found HDL ("good") cholesterol rose: a 3-month trial of an oregano water distillate in 48 adults with mild high cholesterol (Ozdemir 2008), and a 14-day trial of oregano essential oils in 34 athletes (Maral 2022). The only double-blind trial, in 45 healthy men, found no change in blood lipids (Nurmi 2006). Because it is the best-controlled of the three, its null result carries real weight.

Oregano is rich in phenolic compounds, mainly carvacrol, which act as antioxidants. The oregano oils in the athlete trial were 68% and 82% carvacrol (Maral 2022).

In the distillate trial, paraoxonase (an antioxidant enzyme carried on HDL particles) and arterial dilation improved alongside HDL (Ozdemir 2008). That fits a story in which oregano supports HDL function, but it comes from one small trial that did not describe how patients were allocated.

Antioxidant activity doesn't by itself lower LDL, the main target in high cholesterol. A double-blind trial found that oregano phenolics were absorbed, since their excretion rose markedly, yet serum lipids and lipid oxidation markers did not change (Nurmi 2006).

So a plausible mechanism exists for HDL, none is established for LDL, and the clinical effect is unproven.

No dose of oregano oil has been tested in people with high cholesterol. The distillate trial used 25 ml of Origanum onites water distillate after each meal for 3 months (Ozdemir 2008). The athlete trial gave oregano essential oils for 14 days; its abstract does not give the dose (Maral 2022). The null trial used juice providing 300 or 600 mg a day of oregano phenolics for 4 weeks (Nurmi 2006).

None of these is the same as an oregano oil softgel, so a label dose can't be matched to a trial.

In 48 adults with mild high cholesterol who did not need drugs, all received diet and lifestyle advice, and 32 also took an oregano distillate after meals for 3 months. Compared with the 16 controls, they had a greater rise in HDL and greater falls in LDL, apolipoprotein B, lipoprotein(a) and hs-CRP (Ozdemir 2008). The abstract does not say how patients were allocated or whether anyone was blinded, and the controls got no placebo.

In 34 trained athletes randomised to one of two oregano oils, lavender oil or a control group for 14 days, HDL was higher than control with both oregano oils (p = 0.001 and p = 0.024), and LDL fell with one of them (p = 0.023). Total cholesterol and triglycerides did not change (Maral 2022). With about eight people per group and healthy volunteers, this is a signal, not proof.

In a 4-week double-blind randomised trial, 45 healthy non-smoking men drank juice with 0, 300 or 600 mg a day of oregano phenolics. Excretion of phenolic compounds rose markedly in the high-dose group, showing they were absorbed, but serum lipids and markers of lipid oxidation did not change (Nurmi 2006).

These men had normal lipids, which leaves less room to improve, so the trial doesn't rule out an effect in high cholesterol. But it is the best-controlled trial of the three.

No trial has tested oregano oil capsules in people with diagnosed high cholesterol, compared oregano with a proven treatment, or lasted longer than 3 months. None measured heart attacks or strokes. A 2023 scoping review of culinary herbs for metabolic syndrome found no relevant trials of oregano at food doses (Mackonochie 2023).

Options with far more evidence include psyllium, oat beta-glucans and berberine. See all options on our high cholesterol page.

Oregano is generally well tolerated, and stomach upset and allergic skin reactions have been reported only rarely (LactMed). In the 14-day athlete trial, liver markers did not change with oregano oils (Maral 2022), and the double-blind juice trial found no changes in its safety measures (Nurmi 2006).

Allergy is the main documented risk: people sensitised to mint-family herbs can react to oregano, sometimes with systemic reactions (Benito 1996).

Taking it in a combination capsule with black seed oil? See our guide to oil of oregano with black seed oil for side effects and interactions.

No interaction studies exist for oregano oil and cholesterol medicines. In a one-month safety study of purified carvacrol, oregano oil's main compound, prothrombin time (a clotting measure) rose at 1 mg/kg a day, while staying within the normal range (Ghorani 2021).