IGF-1 LR3 which is also known as Long R3 IGF-1, or insulin like growth factor, is a compound that plays a very important role in a wide range of cellular functions including normal growth and health maintenance.  

IGF-1 LR3 is more efficient and potent than IGF-1, and it has a longer lifespan.  Similar in molecular structure to insulin (hence the name), this hormone helps to transfer glucose through the cell membranes and helps to supply the raw materials that cells need for growth and repair including muscle, heart and nerve cells.

Insulin is made in the pancreas and IGF-1 is produced in the liver.  The two hormones work together,back and forth to determine what the body will use as fuel. When you eat, insulin kicks in and the body is fueled by sugar.  During fasting periods, fat is primarily utilized for fuel.  Over time, if the liver becomes fatty, the body can lose the capacity to make IGF 1, thus causing the body to create more insulin, resulting in diabetes.

IGF-1 is produced throughout life, with the highest levels of IGF-1 production occurring during puberty and the lowest levels during infancy and old age.  Production of IGF-1 is stimulated by growth hormone (GH) and can be diminished by many factors including malnutrition, GH insensitivity and lack of GH receptors.  Variation in levels of GH and IGF-1 in the body include: insulin levels, genetics, disease, age, sex, ethnicity, nutrition, stress and fitness level.