The present invention relates to high-efficiency encapsulation of hydrophilic substances in the hydrophilic space of unilamellar liposomes. High-efficiency encapsulation is achieved by the use of a polyhydric alcohol selected from propylene glycol or glycerine for dissolving the hydrophobic compounds forming the lipid bilayer of the liposomes. The invention provides unilamellar liposomes (UL) as well as a method for preparing same by way of low temperature extrusion. The invention also relates to use of these UL in the manufacturing of a medicament, a cosmetic product, a food additive or a disinfectant.