The medical term used for obtaining adult stem cells is harvesting. We typically harvest adult stem cells from bone marrow or fat. Bone marrow adult stem cells were discovered first and have far more studies in the United States. More recently, fat has become a frequently used source for harvesting adult stem cells. Adult stem cells from fat are called adipose derived adult stem cells. Adipose derived adult stem cells have some advantages. There are about 20 times more adult stem cells per milliliter of tissue in fat over bone marrow. In addition, the numbers of adult stem cells in bone marrow decreases with age and disease. Adipose derived adult stem cells change very little in number with age or disease.
Fat is more abundant than bone marrow and less invasive to harvest. For these reasons and others, fat is quickly becoming the tissue of choice for harvesting adult stem cells.