“Stubborn belly fat” is a popular phrase, but it is not a precise research term. In scientific body-composition work, abdominal fat is usually separated into different compartments. Subcutaneous fat sits under the skin. Visceral adipose tissue, often abbreviated VAT, sits deeper in the abdominal cavity around internal organs.

That distinction is essential when discussing tesamorelin. Tesamorelin is a synthetic analog of growth hormone-releasing hormone, commonly abbreviated GHRH. The responsible research frame is not a broad promise around belly fat. It is a narrower discussion about GHRH biology, VAT measurement, and the specific clinical context where tesamorelin has been studied.