d-Lenolate and Hydroxytyrosol 18 are both olive leaf extracts that use our patented extraction process to give your body a longer time to absorb the nutrients from the olive leaf. Where they vary is that while on d-Lenolate we focus on the extraction of Oleuropein, for our Hydroxytyrosol 18 we focus on the extraction of Hydroxytyrosol in addition to Oleuropein. We also utilize a Certificate of Analysis to ensure that every single batch of Hydroxytyrosol 18 has a minimum standard of 18% Hydroxytyrosol and Oleuropein.