Background <p>Tacrolimus is a critical calcineurin inhibitor used in the management of liver transplant recipients. Currently, several pharmaceutical companies have developed and introduced generic formulations of Tacrolimus. Most studies on the use of generic Tacrolimus have focused on the conversion from branded to generic versions in stable patients.</p> Objectives <p>The aim of this study is to assess the efficacy and safety of Suprotac® compared to Prograf®, over a 12-month period in de novo adult liver transplant recipients.</p> Methods <p>This randomized clinical trial was conducted among adult liver transplant recipients at the Shiraz Transplant Center from October 2022 to June 2024. All patients over 18 years of age, with Tacrolimus as part of their post-transplant immunosuppressive regimen, were included in the study. Patients were randomly assigned to two groups: those receiving Suprotac® and those receiving Prograf® for 12 months in de novo manner. All patients were followed up for 12 months post-transplant. The incidence of rejection, graft loss, liver enzyme fluctuations, safety profile, and adverse events were evaluated between the two groups.</p> Results <p>A total of 152 patients participated in this study. The rejection rates were 5.88% in the Suprotac® group and 14.28% in the Prograf® group (p-value:0.093). Mortality rates were 22.05% in the Suprotac® group and 10.71% in the Prograf® group (p-value: 0.056. Additionally, 10 patients experienced graft loss. No significant differences were found between the two groups regarding fluctuations in liver enzymes and renal function. The most commonly reported adverse events in both groups were neurological complications such as headache, and insomnia.</p> Conclusion <p>The findings of this study indicate that de novo use of Suprotac®, compared to Prograf®, offers comparable efficacy in preventing rejection and a similar one-year safety profile in adult liver transplant recipients.</p> Graphical abstract <p></p>