[en] Highlights: • Radiosynthetic optimization of L-[S-methyl-¹¹C]methionine production nearly doubled the absolute radiochemical yield. • In-lab comparison of different synthetic methods for L-[S-methyl-¹¹C]methionine with NaOH or Al₂O₃/KF as base. • Identification of major contributions of activity loss within the synthesizer. - Abstract: Radiosynthetic optimization is crucial in routine PET production but is often neglected in literature. Small changes in the radiochemical procedure can increase the yield significantly and reduce time fluctuation within the synthetic procedure enabling better planning and product release on time. Therefore, a highly reproducible production method for L-[S-methyl-¹¹C]methionine is presented, which uses a fully automated GE TRACERlab FX C Pro synthesizer. Evolution of the synthetic procedure lead to a protocol with a nearly doubled absolute yield.