Background:TheCOVID-19pandemicimposedunprecedentedchallengestohealthcareandpatient well-being worldwide, including Saudi Arabia, yet its long-term impact on stress-relatedendocrine markers and mental health has not been systematically assessed.Objective:Todeterminethelongitudinalchangesinhaircortisol,DHEASlevels,andrelatedmental health diagnoses before, during, and after the COVID-19 pandemic.Methods: We conducted a retrospective cohort study of adult patients admitted to King AbdulazizUniversity Hospital in Jeddah, Saudi Arabia, from January 2019 to September 2024. We extracteddemographicdata,haircortisol,DHEASlevels,cortisol/DHEASratios,andmentalhealthdiagnoses(anxiety,depression,andpost-traumaticstress).Comparisonsweremadebetweenpre-pandemic(2019),pandemic(2020–2021),andpost-pandemic(2022–2024)periodsusingANOVA, chi-square tests, and multivariable regression.Results:Of4,562patientsincludedhaircortisolandcortisol/DHEASratiosweresignificantlyelevatedduringthepandemicphase,accompaniedbyhigherratesofanxietyanddepressiondiagnoses. By the post-pandemic period, there was partial normalization of endocrine and mentalhealth parameters, although values remained higher than pre-pandemic levels.Conclusions: Our findings suggest that the pandemic triggered sustained alterations in stressbiomarkersandmentalhealthinthisSaudicohort.Continuedeffortstosupportpatients’psychological and physiological recovery are warranted, underscoring theneed for integrativepost-pandemic healthcare interventions.