15(R)-Prostaglandin E2, the C-15 epimer of the more physiologically abundant 15(S)-PGE2 (sc-201225) isomer, is produced mainly from arachidonic acid (sc-200770) via the action of COX and PGES enzymes. Present in nearly all cell types, PGE2 interacts with four distinct receptors, EP1 to EP4, leading to a wide range of biological effects. However, 15(R)-Prostaglandin E2 exhibits significantly lower efficacy in most biological assays compared to its 15(S) counterpart. Notably, acid catalyzed epimerization can transform 15(R)-Prostaglandin E2 into the more active 15(S)-Prostaglandin E2 form.