Used in research settings to quantify levels of 6-sulfonylmelatonin, a major metabolite of melatonin, in human urine or serum samples. This ELISA kit enables assessment of melatonin production and pineal gland activity, supporting studies on circadian rhythm regulation, sleep disorders, and the impact of environmental factors like light exposure on melatonin secretion. It is also applied in clinical and epidemiological research investigating metabolic, neurological, and psychiatric conditions where melatonin pathways may be disrupted. The assay provides a sensitive and specific means to monitor melatonin metabolism without the need for radioactive tracers, making it suitable for high-throughput analysis in large-scale studies.