Oleuropein is responsible for that slightly spicy, pungent flavor you’ll encounter in a quality extra-virgin olive oil. But supplement manufacturers are able to produce something called olive leaf extract, which contains a stable, standardized form of oleuropein so you can reap the benefits (in concentrated form) without having to consume huge quantities of olive oil. The most potent active compound in olive leaf extract is oleuropein, but the extract also contains high levels of phenolic and flavonoid compounds (such as luteolin, apigenin, rutin, hydroxytyrosol, verbascoside, and ligstroside)2, which work synergistically with oleuropein to enhance its natural activity. Here’s a rundown of the most promising ways an oleuropein-rich olive leaf extract supplement may affect your health: In fact, olive leaf extract may be just as effective as prescription blood pressure medication for some people. In this study4, participants who took 500 mg of olive leaf extract twice a day for eight weeks experienced a comparable drop in blood pressure to those who took the medication Captopril. Olive leaf extract is thought to lower blood pressure by acting as a calcium channel blocker, which relaxes and widens the blood vessels. In the same study, olive leaf extract also lowered triglyceride levels (i.e., levels of fat in the blood), while Captopril did not. This is important for heart health, as high triglyceride levels contribute to hardening of the arteries, or atherosclerosis, which increases the risk of heart attack and stroke. Supplementing with olive leaf extract has also been found to lower total and LDL (bad) cholesterol in both animals and humans5 with high cholesterol. Researchers suspect that the polyphenols present in olive leaf extract, like oleuropein, decrease the activity of key cholesterol-regulatory enzymes, resulting in reduced cholesterol production. Additionally, olive leaf extract has been shown to stimulate phagocytosis, the process by which cells called phagocytes engulf and destroy harmful foreign particles in our bodies like bacteria and viruses. Anecdotally, people have also found that gargling with olive leaf tea alleviates sore throats, possibly by decreasing inflammation. Research also reveals that olive leaf extract is effective at slowing the progression of certain parasitic infections7, which makes sense since people have been using olive leaf extract to help treat malaria since the 1800s. Other research suggests6 that olive leaf extract can attribute its anti-inflammatory properties to its ability to decrease the production of pro-inflammatory cytokines. Specifically, olive oil polyphenols have been shown to decrease the circulating concentrations of interleukin 6 (IL-6), a pro-inflammatory cytokine that stimulates inflammation in diseases like rheumatoid arthritis and cancer. Oleuropein, the main polyphenol in olive leaf extract, is thought to be responsible for the major anti-cancer, anti-tumor activity10, and several experimental animal studies have found that oleuropein treatment prevents the development of skin11 and breast cancers12. That said, evidence for the cancer-fighting effect of olive leaf extract in humans remains anecdotal, and clinical trials are needed to validate these claims. Some research even suggests that olive leaf extract may help counter the negative metabolic effects of a poor diet. In this animal study14, rats fed a high-carb, high-fat diet developed the classic signs of metabolic syndrome: abdominal fat, high blood pressure, and poor blood sugar control. But when rats were fed this same poor diet along with olive leaf extract, nearly all of these abnormalities improved. Researchers say this strongly suggests that olive leaf extract polyphenols such as oleuropein reverse the chronic inflammation and oxidative stress that trigger these metabolic symptoms. Olive leaf extract offers other neuroprotective perks as well. In one animal study15, pretreating gerbils with olive leaf extract before inducing them with a stroke significantly reduced the damage in their hippocampus, an area of the brain thought to be the center of emotion, memory, and the autonomic nervous system. Researchers speculate that this is due to olive leaf extract’s potent antioxidative properties. It’s also recommended that you take olive leaf extract with food and split doses up throughout your day to avoid stomach irritation. Starting with a lower dose can also help minimize any potential side effects. For capsules, experts typically recommend 500 to 1,000 mg of olive leaf extract per day—a range that’s been shown to deliver significant blood pressure and blood sugar benefits in human studies (however, even higher amounts seem to be well-tolerated). To ensure you’re getting a potent product, look for capsules that are standardized to 18 to 25% oleuropein. As with all supplements, look for one from a reputable brand that has been third-party verified to contain the appropriate ingredients in the correct quantities and is free of contaminants.
