Sudachi (Citrus sudachi) is a small sour citrus. It grows exclusively in Tokushima region of Shikoku island, but is a typical seasoning for Japanese fish cuisine. We have demonstrated that repetitive administration of crude sudachi peel extends life span in diabetic model rats, and successfully identified a couple of molecules and fractions which are beneficial for our health in terms of energy metabolism from peels of sudachi. A limonene-derivative, which turned out to facilitate expression of a longevity gene, sirt1, exhibited lipid-lowering effects in HFD-fed mice as well as in cultured cells, for instance. Our recent results on the metabolic effects of such components in sudachi peel will be shared in the current symposium.