Olive leaf extract comes from the leaves of the olive tree (Olea europaea), not the fruit or its oil. It concentrates oleuropein and other polyphenols, compounds that act as antioxidants in the body.
People commonly reach for it to support immune defenses and heart health. Some also use it in an effort to maintain healthy blood pressure and blood sugar already in the normal range, though the evidence is mixed.
You can find it in capsules, tablets, or liquid extracts, typically standardized to a set oleuropein percentage. Taking it with food lowers the chance of stomach upset.
This extract can drop blood pressure and blood sugar. Talk to your doctor before using it if you take medication for hypertension or diabetes. We lack solid data on its safety during pregnancy or breastfeeding.