Retatrutide is a new entrant into the rapidly-expanding space of anti-obesity peptides. It is known as a GGG tri-agonist. This means that retatrutide works at all of the incretin receptors including GLP-1 and GIP as well as the glucagon receptor itself. Research indicates that retatrutide may be the most effective weight loss peptide yet developed, with some studies showing a rapid and sustained weight loss response as high as 24% of total body weight[1]. Retatrutide is thought to promote weight loss by increasing energy expenditure as well as decreasing energy consumption. It does the former via action at the glucagon receptor and the latter through both central and peripheral appetite control.