By Sree Roy
I leapt up, switched the lights off, and yelped, “Remember—no overhead lights during my saliva test!” As my startled husband and kids began removing their softball cleats in near-total darkness, I fretted about the potential impact on my melatonin onset profile test.
Salivary assays for hormones entwined with sleep rhythms are available direct-to-consumer and by physician referral (no prescription required). I recently took two—Thorne’s four-sample Sleep Test, which analyzes melatonin and cortisol levels ($189), and Salimetrics’ Biology of Sleep Dim Light Melatonin Onset Test + Cortisol, 9 Sample ($300 or $179 for melatonin only)—and found their execution to be slightly more rigorous than taking a typical device-based home sleep test. But I thought the effort was worthwhile. The reports revealed a dimension of my sleep-wake rhythms that I hadn’t explored, despite 11 years of covering sleep.
Sleep physicians already know salivary tests like these can provide evidence for suspected circadian rhythm sleep phase disorders. But what physicians may not realize is the melatonin-cortisol (and, in some tests, insulin) findings can help optimize sleep in patients with other symptoms too. “It’s resonated with physicians who say, ‘I have actigraphy; I have sleep diaries; I have all these other pieces, and it’s nice to have a physiologic driver of circadian biology,’” says Steve Granger, PhD, chief scientific officer at Salimetrics LLC.
These checks—which time-lapse the ramping up and down of hormones, compare them to normative ranges, and, in some cases, pinpoint the time when melatonin rises above a key threshold—can sometimes link a patient’s biology to otherwise confounding sleep problems.
Beyond suspected circadian rhythm sleep disorders, sleep physicians can consider them for patients with:
- sleep disruptions (not already linked to non-circadian sleep disorders like sleep apnea or limb movement disorders) for 14 or more days;
- an interest in starting sleep supplements like melatonin;
- sleep-wake disruptions after starting a new medication or sleep routine; and
- inconsistent results with bright light or cognitive behavioral therapy for insomnia.
Data-Informed Sleep Supplements
Thorne’s test is unique in that it maps a person’s results onto the company’s line of supplements. These include melatonin, magnesium glycinate, and gamma-aminobutyric acid.
While that creates an incentive to recommend products, I (spoiler alert) can attest that the reports do not always recommend supplements. “We don’t want to just push product if we don’t think there’s a reason for it,” says Nathan Price, PhD, chief scientific officer at Thorne. “The point of the Sleep Test is to try to figure out if melatonin or cortisol is the issue and at what points in time they seem to be the problem.” For example, Price says, for people with unusually high cortisol at night, Thorne’s Stress-B-Complex is sometimes recommended.
What about the patients on supplements already?
One option is to take the test as is, which may show that melatonin is never given a chance to dissipate. “We’ve seen people who have maxed-out melatonin levels all day long,” including days after their last dose, says Chris Schwartz, sleep health program administrator at Salimetrics. The delta in daytime versus nighttime melatonin level is what alerts the body to its sleep window, many people surmise, so such a finding could open a discussion into whether having sleep-levels of melatonin all day is linked to the patient’s sleep troubles.
The second is to do a washout period that is probably longer than you would guess. Salimetrics suggests at least 10 days for people who take less than 5 mg of melatonin—and 15 to 20 days for higher doses. After receiving the test results, decide whether supplementation could be helpful.
Optimize Bedtime
Many people determine their bedtime by 1) knowing when they need to wake up, and 2) counting back eight hours.
A dim light melatonin onset (DLMO) profile optimizes bedtime for each individual, Granger posits. “What DLMO has allowed some physicians to do is to pick a time for people to go to bed when they’re most receptive to sleep, which is about two hours after DLMO,” he says. “It’s something you can’t really get without doing the full profile.”
Even if that bedtime is later than the current one and results in less than eight hours of sleep, it could mean better quality sleep. “It’s optimizing your circadian phase, and it could be subtle,” Granger says.
Fix Medication Timing
Salivary melatonin curves (or the lack thereof) can sometimes expose unexpected drug interactions.
In one case, a Salimetrics test-taker had a skyrocketing melatonin level that “went to the moon” and never returned in the morning, Granger says. They denied melatonin supplement use. But when asked about medications, they mentioned taking a selective serotonin reuptake inhibitor at a time that synced up with the runaway result. It seemed the antidepressant was preventing melatonin clearance.
Understanding this interaction gave the option for a practical change: If morning sluggishness is a problem, shift the timing of the antidepressant so nighttime melatonin can clear out.
Find Individual Zeitgebers
One-off results can be enlightening. So too can repeat salivary testing, which can uncover how external cues, or zeitgebers, shape a person’s circadian rhythm.
Some people can align to new routines effortlessly. Others shift slowly—or barely at all. Salimetrics’ Schwartz, while testing himself nightly, found it took 10 days to force his DLMO to entrain to a 3 am bedtime. But it snapped back in just two days when he returned to his 9:30 pm routine. Retesting allows patients to modify, then confirm.
While light is generally considered the strongest zeitgeber, people vary in their sensitivity to it. (For the record, my DLMO profile did not appear to be sabotaged by the errant entryway light.) So if someone starts exercising outdoors in the morning, cuts out supplements, or changes their shower time, retesting could show whether those changes nudged their circadian curve in the right direction. “People will align for different reasons,” Schwartz says.
My Saliva Test Results
As for my profile results, I received the most scientific compliment ever. “You have an amazing cortisol response,” Granger at Salimetrics says as I blush. The report from Thorne also boasts: “sleep cycle: in rhythm;” “wake cycle: in rhythm.”
Both checks also indicated beautifully cycling melatonin, but with the same oddity both times (on different dates): My melatonin rates off-the-charts low when I wake up. “Do you get up and exercise outside in the morning?” Granger asks. “Or maybe the sun is in your eyes, and your body’s pretty receptive to that.” Yes, and yes.
Oh, and based on my 7:45 pm to 8:45 pm DLMO, he added, “Technically, you should probably go to bed a little bit earlier.”
That, to me, is the power of these saliva tests for sleep hormones. I didn’t receive a diagnosis or a product recommendation. I received a physiological map of my internal rhythms—one I can use to fine-tune everything from my bedtime to when I walk the dog. I am lucky in that I took the tests just for fun. For people whom physicians refer to salivary testing for a sleep problem, that data could help recalibrate when they sleep, wake, and relax.
