(R)-(-)-Ibuprofen is the inactive enantiomer of ibuprofen, primarily utilized in pharmaceutical research, chiral synthesis, and as an intermediate for producing the active (S)-(+)-enantiomer. In vivo, it can undergo metabolic inversion to the active form. It is employed in studies investigating enantioselective pharmacology, drug metabolism, and the development of enantiopure formulations. While racemic ibuprofen is widely used as an active pharmaceutical ingredient for alleviating pain, reducing inflammation, and lowering fever in conditions like headaches, dental pain, muscle aches, arthritis, and menstrual cramps, the (R)-enantiomer itself has minimal direct therapeutic activity but is valuable for understanding stereochemical effects and potential side effect profiles.