A recently developed supercritical assisted process, named SAILA (Supercritical Assisted Injection in Liquid Antisolvent) has been used for the production of alpha-tocopherol stable aqueous suspensions. alpha-Tocopherol is a liposoluble vitamin, belonging to the family of Vitamin E, widely used as supplementation and as antioxidant in food, cosmetics and pharmaceutical industries. However, its poor solubility in water, and thus its low bioavailability, make its use problematic. The formulation of this compound in nanosized suspensions is particularly appealing, since it is known that nanoparticles increase the dissolution rate, thus increasing bioavailability. For these reasons, in this work, SAILA has been applied to the production of alpha-tocopherol nanoparticles suspensions. The effect of process parameters such as kind of solvent-antisolvent, concentration of surfactant, concentration of solute, expanded liquid temperature, pressure and composition have been studied. The SAILA process was successful for the production of alpha-tocopherol nanopartides directly stabilized in water suspensions. Changing the operative parameters dimensions have been tuned from micrometric to nanometric scale. In particular, regarding the nanometric scale, stable alpha-tocopherol particles suspensions with mean diameters down to 150 nm have been produced and characterized in terms of morphology, particles size distribution and zeta potentials. Particles are spherical and non-coalescing and suspensions stability during storage at 4 degrees C has been verified for 30 days. 2014 Elsevier Ltd. All rights reserved.