Dim Light Melatonin Onset (DLMO) – Circadian/Sleep Assessment
Convenient at-home saliva collections for evaluating circadian rhythm disorders


Melatonin is a key biomarker for measuring circadian rhythm. In healthy individuals, production of melatonin follows predictable cycles and is suppressed by exposure to daylight. In the evening, melatonin production in the body is expected to rise about 2 hours before the onset of sleep. This is called Dim Light Melatonin Onset (DLMO).

Sample DLMO Report

Knowing the timing of a patient’s nocturnal melatonin secretion reliably evaluates the sleep-wake cycle to determine alignment or misalignment (phase delay or phase advance) from a typical 24-hour entrained circadian clock. Temporal shifts on the phase response curve can indicate abnormal sleep-wake patterns and provide clinicians with important data for sleep disturbance assessment.

BioHealth’s #220 DLMO Profile – Saliva Melatonin

  • 8 measurements of salivary melatonin for determination of DLMO phase
  • An effective alternative to inconvenient collections performed in clinics or labs
  • Performed using the Salimetrics melatonin assay, the industry standard – with higher specificity and consistency between tests, and a lower variability between replicate tests
At-Home Testing DLMO
While commonly performed by patients in sleep clinics for many years, the at-home option for patients to perform DLMO saliva collections at home is a reality now for clinicians assessing circadian rhythm disorders. Patients are required to restrict certain foods and activities on the day of collection. The start time of the 8 hourly saliva collections starts 5 hours previous to the typical time of falling asleep. Restriction of light to > 30 lux is critical to a successful collection procedure, given that excess light will suppress melatonin. The patient stays awake for the entire DLMO collection process, freezes the samples, then ships them to the lab in a thermal container. Device apps like multi-timers and light meters can be downloaded to ensure compliance.

DLMO Tests