A method for preparing a lyophilized lipid nanoparticle, said method comprising: (a) Providing a lipid nanoparticle in an aqueous solution comprising one or more lyoprotectants selected from the group consisting of sucrose, trehalose, dextran and inulin, wherein the lipid nanoparticle is a liposome that encapsulates an mRNA and comprises a cationic lipid, a non-cationic lipid, a PEG-modified lipid and cholesterol; and (b) Lyophilizing the lipid nanoparticle by performing the steps of rapidly freezing and drying the lipid nanoparticle at the temperatures and vacuum conditions provided in Tables 1, 3, 7 or 8: Table 1 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 6 hours H -45 500 R -45 500 H Primary Drying -45 100 60 hours H -35 100 R -35 100 H -30 100 R -30 100 H -20 100 R -20 100 H 0 100 R 0 100 H Secondary Drying 25 100 6 hours R 25 100 H Table 3 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 11 hours H -45 500 R -45 500 H Primary Drying -45 100 61 hours H -35 100 R -35 100 H -30 100 R -30 100 H -20 100 R -20 100 H 0 100 R 0 100 H Secondary Drying 25 100 8 hours R 25 100 H Table 7 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 8 hours H -45 500 R -45 500 H Primary Drying -45 100 69 hours H -35 100 R -35 100 H -30 100 R -30 100 H -20 100 R -20 100 H 0 100 R 0 100 H 25 100 R 25 100 H Secondary Drying 0 100 4 hours Table 8 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 7 hours H -45 500 R -45 500 H Primary Drying -45 100 69 hours H -20 100 R -20 100 H -10 100 R -10 100 H 0 100 R 0 100 H 10 100 R 10 100 H 20 100 R 20 100 H Secondary Drying 0 100 4 hours ; wherein upon reconstitution the lipid nanoparticles have an average particle size of less than 125nm in a PBS solution. (a) Providing a lipid nanoparticle in an aqueous solution comprising one or more lyoprotectants selected from the group consisting of sucrose, trehalose, dextran and inulin, wherein the lipid nanoparticle is a liposome that encapsulates an mRNA and comprises a cationic lipid, a non-cationic lipid, a PEG-modified lipid and cholesterol; and (b) Lyophilizing the lipid nanoparticle by performing the steps of rapidly freezing and drying the lipid nanoparticle at the temperatures and vacuum conditions provided in Tables 1, 3, 7 or 8: Table 1 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 6 hours H -45 500 R -45 500 H Primary Drying -45 100 60 hours H -35 100 R -35 100 H -30 100 R -30 100 H -20 100 R -20 100 H 0 100 R 0 100 H Secondary Drying 25 100 6 hours R 25 100 H Table 3 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 11 hours H -45 500 R -45 500 H Primary Drying -45 100 61 hours H -35 100 R -35 100 H -30 100 R -30 100 H -20 100 R -20 100 H 0 100 R 0 100 H Secondary Drying 25 100 8 hours R 25 100 H Table 7 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 8 hours H -45 500 R -45 500 H Primary Drying -45 100 69 hours H -35 100 R -35 100 H -30 100 R -30 100 H -20 100 R -20 100 H 0 100 R 0 100 H 25 100 R 25 100 H Secondary Drying 0 100 4 hours Table 8 Phase Temperature (°C) Vacuum (mTorr) Time Ramp/Hold Freezing 5 500 7 hours H -45 500 R -45 500 H Primary Drying -45 100 69 hours H -20 100 R -20 100 H -10 100 R -10 100 H 0 100 R 0 100 H 10 100 R 10 100 H 20 100 R 20 100 H Secondary Drying 0 100 4 hours ; <EOS>