Salivary Melatonin Profile: At-Home and Finger-Prick Options Explained

What does a salivary melatonin profile measure?

Melatonin is a hormone the brain produces in response to darkness; it helps time circadian rhythms and sleep, and light at night can block its production [3]. Under dim light in the evening, melatonin concentrations rise; the onset of that rise is DLMO. Consensus guidance derived through a modified RAND process covers how to collect and analyze salivary, plasma and urinary melatonin and how to define DLMO, and recommends that reports include an established low-threshold DLMO measure so results from different laboratories can be compared [1]. DLMO is the single most accurate marker for assessing the circadian pacemaker, used to judge whether someone is synchronized to a 24-hour day, whether their rhythm has shifted, and when to time bright light or exogenous melatonin [2].

Can you collect a melatonin profile at home?

The consensus guidance covers collection in a person's natural living environment as well as in a clinic or research unit [1]. DLMO is defined as the onset of melatonin secretion under dim light conditions [2], and light at night can block melatonin production [3].

What about finger-prick cards?

The consensus guidance on measuring melatonin covers saliva, plasma and urine; finger-prick dried blood spots are not among the sample types it addresses [1].

What can change the result?

• Beta-blockers. The Hetlioz (tasimelteon) label states that beta-adrenergic receptor antagonists have been shown to reduce melatonin production through specific inhibition of beta-1 adrenergic receptors, and that nighttime dosing may reduce the drug's efficacy [4].
• Fluvoxamine. In five healthy men given 5 mg of oral melatonin, 50 mg of fluvoxamine increased serum melatonin exposure about 17-fold and peak concentration about 12-fold [5]. This study did not test whether fluvoxamine changes the timing reported by a salivary DLMO profile.
• Melatonin supplements. Supplements may contain substantially more or less melatonin than their labels state. In a 2023 analysis of 25 melatonin gummy products, 22 were inaccurately labeled. Among the 24 that contained melatonin, measured content ranged from 74% to 347% of the labeled amount; one product labeled 5 mg melatonin had no detectable melatonin and contained 31.3 mg of CBD [6][7]. An earlier analysis of 31 supplements found melatonin content from 83% below to 478% above the label, and serotonin in 8 of them [8].

Does a profile decide treatment?

No. The American Academy of Sleep Medicine's 2015 guideline endorses strategically timed melatonin for delayed sleep-wake phase disorder, blind adults with non-24-hour sleep-wake rhythm disorder, and children and adolescents with irregular sleep-wake rhythm disorder plus neurological comorbidity, and recommends against melatonin in elderly patients with dementia [10]. Melatonin is sold as a dietary supplement [11], and melatonin products are not approved by the FDA [7].