Hydroxytyrosol is a polyphenol found in olives, olive oil and olive leaves. Among other things, it forms when oleuropein breaks down as the olive ripens and is processed. Hydroxytyrosol is one of the most studied components of the olive.
How much an oil contains depends strongly on the variety, the harvest and how it is processed. Fresh olives that are pressed quickly tend to give oils richer in these compounds.
