D-Methionine is widely used in pharmaceutical and nutraceutical applications, particularly for its protective effects on the auditory system. It is employed as a preventive agent against ototoxicity caused by certain antibiotics and chemotherapy drugs, helping to reduce hearing loss without interfering with the efficacy of the treatments. Its antioxidant properties contribute to cellular protection by scavenging free radicals and supporting liver detoxification processes. In research settings, D-Methionine is used to study amino acid metabolism and neurological function. It is also utilized in specialized diets and clinical formulations aimed at supporting metabolic health, especially in individuals with specific sulfur-containing amino acid requirements.