Disclosed are cell-penetrating cyclic peptides. The peptides can be used to deliver peptides and other biologically active moieties into cells. Formulations containing the cell-penetrating cyclic peptides are also described.揭示細胞穿透環肽。該等肽可用於傳遞肽及其他生物活性部份至細胞中。亦描述含有細胞穿透環肽之配方。