A total of 30 participants with subjective cognitive decline or perceived cognitive impairment were administered one HSOP capsule containing 0.5 mg of scallop-derived plasmalogen once daily for 90 days. Changes in cognitive function were evaluated using two validated assessment scales: the Abbreviated Mental Test Score (AMTS) and the Standardized Mini-Mental State Examination (SMMSE). The results demonstrated a statistically significant increase in AMTS scores, from 9.267 to 9.800 (*p = 0.001), as well as a statistically significant increase in SMMSE scores, from 27.267 to 28.533 (***p < 0.001).