In addition, many studies have shown that pro-inflammatory cytokines, such as tumor necrosis factor (TNF) (Sethi and Hotamisligil, 2021), interleukin 6 (IL-6) (Han et al, 2020; Wedell-Neergaard et al, 2019), IL-1β (de Baat et al, 2023), and interferon-gamma (IFN-γ) (Bradley et al, 2022), can influence insulin resistance, adipose tissue inflammation and regulate obesity-related metabolism. Here, IL6 is linked to obesity due to melanocortin 4 receptor deficiency.