Abstract: A heat pipe material suitable for making wearable garments is disclosed. The material has a sandwich structure including a conduction layer, a separation layer, a wick layer and an insulating layer. The conduction layer is made of discs of a rigid, thermal conducting material connected by a flexible, impermeable material. The separation layer is flexible, porous to gas and maintains a separation between the outer layers. The wick layer transfers a working fluid by capillary action. The insulating layer is the outer skin of the garment made from the heat pipe material and is flexible, impermeable to air and has a low thermal conductance. To create a functioning heat pipe, the material is sealed about its periphery and contains a working fluid. A thermal source is functionally connected to the working fluid. The heat pipe garment help maintains a wearer's body temperature close to 37 degrees Celsius.