Seagate uses their own olive leaves to produce this extract, maintaining complete quality control from farm to the finished product. The olive trees are grown on Seagate's farm, and our employees hand select our olive leaves immediately after the olives are harvested each winter, at the moment of the highest level of phytochemical and antioxidant activity once the fruit has ripened. Seagate processes this extract in our own factory by cold-press freshwater extraction, without the use of any chemicals, solvents, or alcohol. Each batch has been tested by independent laboratories for quality and purity at four points during the harvesting and production process. Seagate Products Olive Leaf Extract Supplements contain antioxidants and natural phytochemicals including Oleuropein, Caffeic Acid, Verbascoside, Luteolin 7-O-glucoside, Rutin, Apigenin 7-O-glucoside, Luteolin 4-O-glucoside, and Maslinic Acid. Oleuropein content by itself is not a measure of strength of this herbal concentrate. Seagate Products produces over 19 products from their own olive oil and olive leaves. Real manufacturing means actually producing the raw material and processing it into the finished product.