An extract of Citrus depressa, preferably a water and/or organic solvent extract of a fruit of leaf of Citrus depressa, a supercritical extract of a fruit of leaf of Citrus depressa, or a subcritical extract of a fruit of leaf of Citrus depressa, which comprise 0.3 mass % or more of a polymethoxyflavonoid more than in terms of solid matter, for example, an extract of Citrus depressa comprising 0.2 mass % or more of nobiletin and/or 0.1 mass % or more of tangeretin in terms of solid matter, or a polymethoxyflavonoid such as nobiletin or tangeretin is used as an active ingredient of an IGF-1 production-promoting agent.
