Background: Quantification of levonorgestrel (LNG) remaining is crucial for understanding drug release, effectiveness, and potential for extended use beyond the labeled duration of contraceptive implants. The current study aimed to compare and characterize in vivo rate of LNG released from two types of implants, Femiplant (FP) and Levoplant (LP) users in Bangladesh. Methods: Between July and December 2025, explant sets were collected from reproductive age women who had an implant removed at four family planning settings and residual LNG was quantified using a validated reverse-phase high-performance liquid chromatography (RP-HPLC) method. Baseline LNG load was also determined from six unused implants of both FP and LP. Release kinetics were analyzed to identify the models that best fit the data. We determined Pregnancy rates using Pearl Index and recorded self-reported side-effects. Results: Mean baseline LNG load for FP and LP were 152.15 mg and 149.98 mg, respectively. Mean LNG residual per set of explants was 21.40 ± 3.05 (95% CI: 20.11–22.69) and 21.63 ± 2.70 (95% CI: 20.49–22.77), while LNG (%) of 76.0 ± 1.2 (95% CI: 75.5-76.8) and 74.3±1.5 (95% CI:73.5-75.1) were released from FP and LP, respectively. Additionally, f1 (difference factor) and f2 (similarity factor) estimated were 11.7 (95% CI: 9.5-17.8) and 62.5 (95% CI: 55.6-76.8) for fresh FP and LP, respectively. No pregnancy and serious adverse effect were observed, except implant related side effects such as irregular menstruation and bleeding pattern change. Overall satisfaction was 90.7% for FP, and 96.8% for LP and all participants continued implants for three years. Conclusion: FP could perform clinically similarly to LP as a long-acting reversible contraceptive implant demonstrating contraceptive effectiveness, safety, and acceptability with respective duration of action.