To examine the diverse effects of cilostazol on PCSK9 expression in obese and non-obese participants, we analyzed PCSK9 data from a prospective clinical trial and found that cilostazol treatment significantly reduced serum PCSK9 levels in patients with obesity (369.75 ± 30.94 vs. 243.27 ± 23.36 ng/mL, p < 0.001) but not in those without obesity (276.26 ± 24.57 vs. 243.98 ± 32.14 ng/mL, p = 0.178). Here, PCSK9 is linked to obesity due to melanocortin 4 receptor deficiency.