What is the Origin of Melatonin Onset Measurement?

The concept and methodology were developed in chronobiology research, specifically to find a robust, non-invasive biomarker for the internal biological clock. The term 'onset' emphasizes the beginning of the nocturnal rise, and 'melatonin' names the primary hormone of darkness. The DLMO standard has become the gold standard for clock phase assessment, replacing less precise self-reported sleep times.

What is the Mechanism of Melatonin Onset Measurement?

Melatonin synthesis and release are governed by the Suprachiasmatic Nucleus (SCN), the master clock, which inhibits the pineal gland during the day. As light levels diminish in the evening, the SCN releases its inhibition, allowing the pineal gland to convert serotonin to N-acetylserotonin and then to melatonin. The DLMO is typically measured by taking serial saliva or blood samples in dim light, with the onset defined as the time the melatonin concentration exceeds a specific threshold above the daytime baseline.

Melatonin Onset Measurement ∞ Area

Melatonin Onset Measurement

Meaning

Melatonin Onset Measurement refers to the clinical procedure used to determine the Dim Light Melatonin Onset (DLMO), which is the precise time when the pineal gland begins to significantly increase melatonin secretion in the evening under dim light conditions. The DLMO is the most reliable physiological marker for assessing the phase, or timing, of the body’s master circadian clock. Accurate measurement is crucial for diagnosing circadian rhythm sleep disorders and for timing chronotherapeutic interventions, such as light therapy or exogenous melatonin administration.