<p>Fatty acid desaturases are key enzymes in lipid metabolism, crucial for converting saturated fatty acids into monounsaturated fatty acids. This review examines the roles of stearoyl-CoA desaturase, fatty acid desaturase 1, fatty acid desaturase 2 and fatty acid desaturase 3 in health and disease, highlighting their impact on cellular functions such as membrane fluidity, signalling and energy homeostasis. Dysregulation of desaturase activity can have significant implications for human health, contributing to the development of various pathological conditions, including cardiovascular disease, metabolic disorders and cancer. Fatty acid desaturase 1 and fatty acid desaturase 2 overexpression in cancer correlates with tumour growth and chemoresistance, marking them as potential therapeutic targets. The development of inhibitors targeting stearoyl-CoA desaturase and fatty acid desaturase 1 offers promising therapeutic avenues for metabolic diseases and cancer. This review underscores the critical roles of desaturases in various diseases. It emphasises the need for ongoing research to develop effective diagnostic, prognostic and therapeutic strategies, ultimately improving patient outcomes in altered fatty acid metabolism conditions.</p>