Olive Leaf Extract 40% Oleuropeins. Used by Doctors, Health Professionals and Pharmacies. PHS Olive Leaf Extract has the strongest % of Oleuropeins active ingredient available. Oleuropeins have well defined scientific research supporting their health benefits. Health claim regulations do not allow us to list them here. Independent research is recommended. Pacific Health's Olive Leaf Extract has the strongest Oleuropein potency available. Use the choice of professionals - PHS Olive Leaf Extract -