This study investigates the performance of three types of gel electrolytes—hydrogels, iongels, and eutectogels—used in organic electrochemical transistors (OECTs). The research highlights the superior performance of eutectogels, which consist of poly(glycerol 1,3-diglycerolate diacrylate) as the polymer matrix and choline chloride combined with 1,3-propanediol deep eutectic solvent as the ionic component. Eutectogels outperform hydrogels and iongels in both p-type depletion and p-type/n-type enhancement mode OECTs, demonstrating higher signal amplitudes and signal-to-noise ratios (SNRs) in simulated electrocardiogram (ECG) recordings. The eutectogel-integrated OECTs exhibit exceptional operational stability, with no degradation in SNR over 5 hours of continuous operation and 30 days of daily measurements. These findings underscore the potential of eutectogels as a semisolid electrolyte for OECTs, particularly in applications requiring robust and prolonged physiological signal monitoring.This study investigates the performance of three types of gel electrolytes—hydrogels, iongels, and eutectogels—used in organic electrochemical transistors (OECTs). The research highlights the superior performance of eutectogels, which consist of poly(glycerol 1,3-diglycerolate diacrylate) as the polymer matrix and choline chloride combined with 1,3-propanediol deep eutectic solvent as the ionic component. Eutectogels outperform hydrogels and iongels in both p-type depletion and p-type/n-type enhancement mode OECTs, demonstrating higher signal amplitudes and signal-to-noise ratios (SNRs) in simulated electrocardiogram (ECG) recordings. The eutectogel-integrated OECTs exhibit exceptional operational stability, with no degradation in SNR over 5 hours of continuous operation and 30 days of daily measurements. These findings underscore the potential of eutectogels as a semisolid electrolyte for OECTs, particularly in applications requiring robust and prolonged physiological signal monitoring.