Pu-erh Tea starts out as green tea and is then aged, in a dark location, sometimes for years. During this time, yeast grows on the tea causing a secondary oxidation which creates a wonderful, unique flavor! It is also known for it's antioxidant activity, and is used for reducing cholesterol and triglycerides, and improving mental alertness. According to an article by College of Horticulture and Landscape Architecture, Yangtze University, Jingzhou, Hubei 434025, PR China on the NCBI (National Center for Biotechnology Information ) "Lovastatin was not detected in any of the raw Pu-erh tea samples without storage but was found in almost all the ripe Pu-erh tea samples, with lovastatin contents ranging from 20.61 ng/gdw to 226.38 ng/gdw. After five years' storage, the lovastatin levels increased obviously in ripe Pu-erh tea samples and 55% of raw Pu-erh tea samples from 2007 were found to contain lovastatin with concentrations ranging between 28.41 ng/gdw and 228.61 ng/gdw. With increasing storage time, lovastatin concentration in ripe Pu-erh tea, and the occurrence and concentration of lovastatin for raw Pu-erh tea increased significantly." You can read the entire article here: https://www.ncbi.nlm.nih.gov/pubmed/23587710
Most importantly, however, Pu-erh Tea is delicious! One pot can be brewed quite a few times without losing flavor and it can be stored for years! You can find quality Pu-erh Tea here.