Diabetes mellitus is a serious threat to human health in both developed and developing countries. Optimal disease control requires the use of a diet and a combination of several medications, including oral hypoglycemic agents such as α-glucosidase inhibitors. Currently, the arsenal of available drugs is insufficient, which determines the relevance of studying new potent α-amylase inhibitors. We implemented the recombinant production of sea anemone derived α-amylase inhibitor magnificamide in Escherichia coli. Peptide was isolated by a combination of liquid chromatography techniques. Its folding and molecular weight was proved by ¹H NMR and mass spectrometry. The K_i value of magnificamide against human pancreatic α-amylase is 3.1 nM according to Morrison equation for tight binding inhibitors. Our study of the thermodynamic characteristics of binding of magnificamide to human salivary and pancreatic α-amylases by isothermal titration calorimetry showed the presence of different binding mechanisms with Kd equal to 0.11 µM and 0.1 nM, respectively. Experiments in mice with streptozotocin-induced diabetes mimicking diabetes mellitus type 1 were used to study the efficiency of magnificamide against postprandial hyperglycemia. It was found that at a dose of 0.005 mg kg^–1, magnificamide effectively blocks starch breakdown and prevents the development of postprandial hyperglycemia in T1D mice. Our results demonstrated the therapeutic potential of magnificamide for the control of postprandial hyperglycemia.