Background: Mitochondrial dysfunction is considered an important mechanism in the pathogenesis of various diseases. Therefore, mitochondria are currently being considered as subjects for targeted therapies, particularly, phototherapy using 5-aminolevulinic acid. This study aimed to investigate the activity of mitochondria in cells with different mutation loads. Materials and Methods: The study was conducted using 11 cybrid lines obtained from the THP-1 cell line (a human monocytic leukemia cell line) and platelets of patients with different mitochondrial mutations. Results: Our results illustrate that 5-aminolevulinic acid was metabolized equally in all cell lines, however, there was a significant decrease in mitochondrial potential, which differed among lines. Conclusions: The results of this study can be used to develop a personalized therapeutic approach based on different mitochondrial activities.