Literature reviews do not entirely agree on the impact of obesity on CYP isoforms activity, indicating reduced activity of CYP3A4/5 [27,29] (inconclusive in [28]), CYP1A2 [29] (not confirmed by [27]), and CYP2C9 [29] (not confirmed by [27]), CYP2C19 [27] (inconclusive in [29]). Here, CYP2C9 is linked to obesity due to melanocortin 4 receptor deficiency.