Melatonin Testing Update
by Mark Newman, MS
Testing for melatonin is very important however this depends on whether or not your patient is sleeping and if they take melatonin to sleep. Because we are most concerned with cortisol results, the instructions no longer ask patients to discontinue melatonin supplementation for our DUTCH testing. There is limited value in getting off of melatonin supplementation for a true baseline value. In doing so, many disrupt their “normal” sleep pattern and cortisol analysis becomes different than their norm.
Not on Melatonin supplementation?
If the patient does not take melatonin supplements to sleep, do not start taking it before the test in order to assess their baseline levels. If warranted, they may start melatonin supplementation after testing. For the most accurate assessment, you will want your patients to avoid the following foods that may contain melatonin the day of testing: bananas, pineapple, citrus fruit, tart sour cherries, walnuts, corn, rice, and peanuts. Our instructions can be a lot for patients to take in, so this information is NOT included in our test instructions. To optimize melatonin testing for your patient, please ask that they avoid these foods the day of the test.
On Melatonin supplementation for insomnia?
As our preferred approach is to get the most accurate cortisol results, we suggest that if your patient cannot sleep well without melatonin supplements and takes them regularly, they should continue to take the melatonin as usual before bed. It will create a high level of metabolites on the DUTCH test; however, the patient will sleep normally which will result in their normal-for-them cortisol levels. In this scenario, DUTCH melatonin results will NOT be helpful in assessing the melatonin therapy.
On Melatonin supplementation but want a baseline?
If you, as their clinician, want to know their melatonin and cortisol levels without supplementation, we suggest having them stop the melatonin supplement for 2-3 days prior to testing so that their melatonin levels will go back to baseline. Limited data implies that baseline levels can be seen by just skipping melatonin supplementation the day of the test, but at least one more day should be skipped to ensure accurate results. Understand that this may cause them to have insomnia which may interfere with their cortisol results.
Melatonin is a hormone produced in the pineal gland in response to light therefore, among many things, it regulates the sleep-wake cycle or circadian rhythm. Some melatonin is also made in the gut. As light fades in the evening, the pineal gland begins to produce melatonin to induce a normal sleep pattern. Melatonin is important because it is a potent antioxidant, immune system modulator, promoter of growth hormone production and can improve those affected by seasonal affective disorder (SAD). Therefore, low levels of melatonin can cause sleep issues (falling or staying asleep), weaker immune systems, mood changes, fatigue, and low growth hormone.
Avoiding the bright light of phones, computers, television, and tablets before bed then sleeping in total darkness is critical to healthy production. In addition, high stress, particularly elevated cortisol at night, is suppressive to the pineal gland causing lower levels of melatonin. On the other hand, slightly elevated levels may be due to the supplements tryptophan or 5HTP (as both promote serotonin and serotonin can convert into melatonin) and SSRI’s (particularly fluoxetine) or MAO inhibiting medications.
In urine we measure 6-Hydroxymelatonin-sulfate. Studies have shown that monitoring this metabolite in the urine collected upon waking (which is what we do) correlates beautifully to the night’s production of melatonin. The test does not, however, work when taking oral melatonin as the urine is flooded with gut metabolites. These metabolites do NOT represent circulating melatonin levels.
If you have any questions, please feel free to let us know.