(-)-Ternatin (1), a highly N-methylated cyclic heptapeptide, is a potent inhibitor of fat accumulation against 3T3-L1 murine adipocytes (EC50 = 0.14 microg/mL) [Shimokawa, K.; Mashima, I.; Asai, A.; Yamada, K.; Kita, M.; Uemura, D. Tetrahedron Lett. 2006, 47, 4445]. Compound 1 was synthesized from Boc-protected amino acids in solution. Upon treatment with 1 at 5 mg/kg/day, increases in body weight and fat accumulation in high-fat-fed mice were both significantly suppressed.