Oregano oil and the carvacrol it contains may be nearly as effective at fighting bacteria as some antibiotics.
Staphylococcus aureus bacteria are one of the most common causes of infection. They cause ailments including food poisoning and skin infections.
One particular study looked at whether oregano oil improved the survival of mice infected with Staphylococcus aureus.
Six out of 14 (43%) of the mice given oregano oil lived past 30 days, a survival rate nearly as high as the 7 out of 14 (50%) survival rate for mice that received regular antibiotics.
Research has also shown that oregano oil taken by mouth can be effective against types of bacteria that can become resistant to antibiotics.
This includes Pseudomonas aeruginosa and E. coli, both of which are common causes of urinary tract and respiratory tract infections.
Studies have shown that oregano oil may help lower cholesterol.
In one study, 48 people with mildly high cholesterol were given diet and lifestyle advice to help lower their cholesterol. Thirty-two participants were also given 0.85 ounces (25 ml) of oregano oil after each meal.
After three months, those given the oregano oil had lower “bad” LDL cholesterol, and higher "good" HDL cholesterol, compared to those just given diet and lifestyle advice.
Carvacrol, the main compound in oregano oil, has also been shown to help lower cholesterol in mice that were fed a high-fat diet over 10 weeks.
The mice given carvacrol alongside the high-fat diet had significantly lower cholesterol at the end of the 10 weeks, compared to those that were just given a high-fat diet.
The cholesterol-lowering effect of oregano oil is thought to be the result of the phenols carvacrol and thymol.
Antioxidants help protect the body from damage caused by free radicals.
It is thought that free radical damage plays a role in aging and the development of some diseases, such as cancer and heart disease.
Free radicals are everywhere, and are a natural product of metabolism.
However, they can build up in the body through exposure to environmental factors, such as cigarette smoke and air pollutants.
One study compared the antioxidant content of 39 commonly used herbs, and found that oregano had the highest concentration of antioxidants.
It found that oregano contained 3–30 times the levels of antioxidants in the other herbs studied, which included thyme, marjoram and St. John's wort.
Oregano also has 42 times the antioxidant level of apples and four times that of blueberries, gram per gram. This is thought to be mostly due to its rosmarinic acid content.
Because oregano oil is very concentrated, you need much less oregano oil to get the same antioxidant benefits as you would with fresh oregano.
Yeast is a type of fungus. It can be harmless, but overgrowth can result in gut problems and infections, such as thrush.
The most well-known yeast is called Candida, which is the most common cause of yeast infections worldwide.
In test-tube studies, oregano oil has been found to be effective against five different types of Candida, such as those that cause infections in the mouth and vagina. In fact, it was more effective than any other essential oil tested.
Test-tube studies have also found that carvacrol, one of the main compounds of oregano oil, is very effective against oral Candida.
High levels of the yeast Candida have also been associated with some gut conditions, such as Crohn’s disease and ulcerative colitis.
A test-tube study of the effectiveness of oregano oil on 16 different strains of Candida concluded that oregano oil may be a good alternative treatment for Candida yeast infections. However, more research is needed.
Oregano may benefit gut health in a number of ways.
Gut symptoms such as diarrhea, pain and bloating are common and can be caused by gut parasites.
One study gave 600 mg of oregano oil to 14 people who had gut symptoms as a result of a parasite. After daily treatment for six weeks, all participants experienced a reduction in parasites, and 77% were completely cured.
Participants also experienced a reduction in gut symptoms and tiredness associated with the symptoms.
Oregano oil may also help protect against another common gut complaint known as "leaky gut". This happens when the gut wall becomes damaged, allowing bacteria and toxins to pass into the bloodstream.
In a study on pigs, oregano oil protected the gut wall from damage and prevented it from becoming “leaky.” It also reduced the number of E. coli bacteria in the gut.
Inflammation in the body is linked to a number of adverse health effects.
Research has shown that oregano oil may reduce inflammation.
One study found that oregano oil, along with thyme oil, reduced inflammatory markers in the blood in mice that had artificially induced colitis.
Carvacrol, one of the key components in oregano oil, has also been linked to reducing inflammation.
One study directly applied different concentrations of carvacrol to the swollen paws or ears of mice. Carvacrol reduced paw swelling by 35–61% and ear swelling by 33–43%.
Oregano oil has been investigated for its painkilling properties.
One study in mice tested standard painkillers and essential oils, including oregano oil, for their capacity to relieve pain.
It found that oregano oil significantly reduced pain in mice, with effects similar to the commonly used painkillers fenoprofen and morphine.
The research proposed these results were likely due to the carvacrol content of oregano oil.
A similar study found that oregano oil not only reduced pain in rats, but that the response was dose-dependent. That is, the more oregano oil the rats consumed, the less pain they appeared to feel.
A few studies have indicated that carvacrol, one of the compounds of oregano oil, may have cancer-fighting properties.
In studies on cancer cells in test tubes, carvacrol has demonstrated promising results against lung, liver and breast cancer cells.
It has been found to inhibit cell growth and cause cancer cell death.
Although this is promising research, there have not been any studies carried out on people, so more research is needed.
Thanks to oregano oil’s carvacrol content, it may help with weight loss.
In one study, mice were either fed a normal diet, a high-fat diet or a high-fat diet with carvacrol. Those given carvacrol alongside their high-fat diet gained significantly less weight and body fat compared to those just given a high-fat diet.
Furthermore, carvacrol appeared to reverse the chain of events that can lead to the formation of fat cells.
More research is needed to demonstrate that oregano oil has a role in weight loss, but it may be worth trying as part of a health diet and lifestyle.