A reusable self-heating hair roller includes a fluid holding body containing a supercoolable fluid. The fluid holding body may be implemented in many ways, including as non-permeable, incorruptible, air-tight film, bladder or casing. The supercoolable fluid, such as sodium acetate or equivalent, uses thermochemistry to produce on command an exothermic crystallization process that generates the heat needed to style and or curl the hair. A nucleation initiator initiates a nucleation event that propagates the crystallization to harnesses the latent heat of fusion and create the heat. The nucleation initiator may be situated so that it is generally sequestered or otherwise held in a way where it is prevented from free floating within the supercoolable fluid, yet at the same time remains in full communication with the fluid.