Melatonin

Measuring melatonin levels requires careful consideration of timing and methodology, as the hormone follows a distinct circadian rhythm with dramatic fluctuations throughout the 24-hour cycle.

**Saliva Testing**
Saliva tests represent the most common and convenient method for measuring melatonin levels. Salivary melatonin concentrations parallel those found in plasma, with saliva concentrations approximately 30% of plasma levels [4]. The non-invasive nature of saliva collection makes it ideal for multiple sampling throughout the day and night. Participants can easily collect samples using passive drool methods, and samples can be collected at specific times to assess circadian rhythm patterns [4].

**Blood Tests**
Serum melatonin measurements through blood tests provide accurate assessments of circulating hormone levels, typically performed in clinical settings. Blood tests are particularly useful for diagnostic purposes but are more invasive than saliva testing and require professional collection.

**Urine Tests**
Urine tests measure 6-sulfatoxymelatonin, the primary metabolite of melatonin excreted in urine. This method provides information about melatonin production over time and can be particularly useful for assessing overall melatonin metabolism. 24-hour urine collection methods offer comprehensive circadian rhythm assessment by capturing the complete daily cycle of melatonin production and excretion.

**Specialized Profiles**
Dim Light Melatonin Onset (DLMO) testing represents a gold standard for assessing circadian rhythm timing. This specialized test measures the time when melatonin levels begin to rise in dim light conditions, typically occurring 2-3 hours before natural bedtime. DLMO testing requires multiple saliva samples collected every 30-60 minutes during evening hours under controlled lighting conditions [4].

**At-Home Testing**
At-home test kits are increasingly available for salivary melatonin measurement, allowing individuals to collect samples in their natural environment and send them to laboratories for analysis. These kits typically include specific collection protocols to ensure sample integrity and accurate results [4].

Melatonin levels vary significantly throughout the 24-hour cycle, with dramatic differences between daytime and nighttime concentrations. Understanding normal ranges is essential for interpreting test results and identifying potential circadian rhythm disorders.

**Normal Nighttime Levels**
Healthy adults typically exhibit peak nighttime melatonin levels between 10-80 pg/mL in saliva, with the highest concentrations occurring between 2-4 AM [4]. These peak levels represent the natural surge that promotes sleepiness and maintains sleep throughout the night. The timing and magnitude of this peak are crucial indicators of healthy circadian rhythm function.

**Daytime Levels**
During daylight hours, melatonin levels should remain very low, typically less than 3 pg/mL in saliva [4]. This suppression of melatonin during daytime hours is essential for maintaining alertness and proper circadian rhythm function. Elevated daytime melatonin levels may indicate circadian rhythm disruption or other underlying health issues.

**Age-Related Changes**
Melatonin production undergoes significant age-related decline, with production decreasing substantially after age 50. Elderly individuals typically have approximately 50% less melatonin production compared to young adults [5]. This natural decline may contribute to age-related sleep disturbances and increased vulnerability to circadian rhythm disorders.

Children and teenagers generally exhibit higher natural melatonin production, with particularly elevated levels during pubertal development. The robust melatonin production during youth supports the longer sleep requirements and deeper sleep patterns characteristic of growing individuals [2].

**Gender Differences**
Gender differences in melatonin production are generally minimal in healthy adults. However, women may experience slightly higher melatonin levels during their reproductive years, potentially related to hormonal fluctuations associated with the menstrual cycle. These differences are typically not clinically significant but may influence individual responses to melatonin supplementation.

**Individual Variations**
It's important to note that significant individual variations exist in melatonin production, even among healthy individuals. Factors such as genetics, lifestyle, light exposure patterns, and overall health status can influence natural melatonin levels. Therefore, reference ranges should be interpreted within the context of individual circumstances and clinical presentation.

Optimizing natural melatonin production involves a combination of lifestyle modifications, environmental controls, and potentially dietary interventions or supplementation under medical guidance.

**Sleep Hygiene and Schedule Consistency**
Maintaining a consistent sleep schedule is fundamental for healthy melatonin production. Going to bed and waking up at the same times daily helps reinforce the body's natural circadian rhythms and optimize the timing of melatonin release. Creating a relaxing bedtime routine and ensuring adequate sleep duration (7-9 hours for most adults) supports natural melatonin cycles [2].

**Light Management**
Since melatonin production is triggered by darkness and suppressed by light, managing light exposure is crucial. Reducing blue light exposure in the evening using blue light blocking glasses, apps, or filters can help maintain natural melatonin production. Creating a dark, cool sleeping environment with blackout curtains or eye masks further supports optimal melatonin levels [2].

Conversely, getting natural sunlight exposure during the day, especially in the morning, helps regulate circadian rhythms and ensures proper melatonin timing. Bright light exposure during daytime hours helps suppress daytime melatonin and strengthens the contrast between day and night hormone levels.

**Dietary Sources and Nutrition**
Researchers have found that foods high in melatonin can raise melatonin levels in the blood [2]. Tart cherries are among the richest natural sources of melatonin, with studies showing that tart cherry juice consumption can increase melatonin levels and improve sleep quality. Other foods that contain melatonin include walnuts, almonds, and foods rich in tryptophan, which serves as a precursor to serotonin and subsequently melatonin [2].

**Lifestyle Modifications**
Avoiding screens and electronic devices before bedtime helps prevent blue light suppression of melatonin. Regular exercise, preferably earlier in the day, can support healthy circadian rhythms and improve natural melatonin production. Limiting caffeine and alcohol consumption, particularly in the evening hours, also supports optimal melatonin function.

**Supplementation Considerations**
When lifestyle modifications are insufficient, melatonin supplementation may be considered under medical guidance. Experts recommend starting with low doses of 0.5-3 milligrams for sleep-related issues, as higher doses may cause daytime drowsiness [2]. Since melatonin is a hormone, supplementation should be discussed with healthcare providers, particularly for children who should not take melatonin without medical approval [2].

**Timing and Dosage**
The timing of melatonin supplementation is crucial for effectiveness. Taking melatonin 1-3 hours before desired bedtime typically provides the best results for sleep onset. It's important to note that melatonin supplements are generally safe and not habit-forming, but they can interfere with some prescription medications and may cause side effects such as headache, nausea, drowsiness, and dizziness [2].