Melatonin: A Hormone on the Decline

If you are in midlife (typically between 35-50 years old), your melatonin production has already gone down substantially. By the time you’re in your 40s and beyond, your melatonin will never return to what it was in your younger days. Melatonin is associated with the circadian rhythm, that is, the sleep-wake cycle.

One study shows that the drop in melatonin production coincides with the onset of perimenopause, even if women are still having regular cycles and may be years from menopause. In “Decrease in melatonin precedes follicle-stimulating hormone increase during perimenopause,” researchers studied 77 healthy female volunteers, ages 30-75 years old. They found that, within the study group, those ages 30-39 had the highest levels of melatonin, but women in the next age bracket (40-44) excreted 41 percent less melatonin! Older women also experienced another sharp drop in melatonin production, going down by another 35 percent between ages 50-59.

This means that melatonin and follicle stimulating hormone, or FSH, have an inverse relationship as it pertains to the onset of perimenopause. Melatonin levels sink way before FSH levels (a measure commonly used to determine if a woman is in menopause) rise. High FSH levels are a sign of impending or completed menopause. That melatonin production declines before FSH climbs is yet another signal that a woman is in perimenopause. Since most doctors don’t test patients’ melatonin levels, there are some signs that a woman in midlife may be experiencing a reduction in natural melatonin, such as:

• Experiencing more difficulty getting to sleep
• Having nighttime awakenings
• Waking up too early

Not so coincidentally, these are the very same type of sleep problems perimenopausal women commonly experience. Sometimes these sleep disruptions occur in tandem with other perimenopausal symptoms like night sweats or anxiety, but often they exist in isolation. Sleep issues as a midlife perimenopausal woman, then, are not dependent on perspiring while asleep or having a mood disturbance, such as depression or anxiety.

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Nighttime melatonin levels by age, Source: Cultura Pierpaoli
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Multiple melatonin studies on perimenopausal and menopausal women show that it may be beneficial to supplement melatonin. In one study, subjects receiving melatonin at a nightly 3 mg dose reported sleeping and feeling better. Another study found that the time it took to go to sleep lessened in a group being treated with melatonin, and participants did not develop a tolerance to melatonin or experience a return of insomnia when melatonin administration was discontinued.

Overall, some researchers say that “short-term usage of melatonin is a rational therapeutic approach for the alleviation of insomnia or circadian phase disorders of peri- and post-menopausal women, as these periods of life are characterized by changes in sleep quality and circadian rhythms.”

What “short-term” usage means has not been clearly defined, as studies on melatonin have yet to define precise guardrails around its use. It is generally well tolerated and deemed safe. For those who take supplemental melatonin, experts suggest taking it between 8-10 p.m., as that helps it coincide with its natural peak in the body between 2-4 a.m. Also, doses up to 5 mg have been most studied, with general current guidance suggesting that doses over 5 mg are not necessarily more helpful.

Melatonin is available over the counter (OTC) in the U.S. in a variety of forms – gummies, liquid, capsules, caplets and extended-release versions. Though OTC medicines and supplements don’t require a prescription to purchase, since supplements and vitamins are not regulated like prescription drugs, it is advised to consider using a third-party source to evaluate the safety of supplements. ConsumerLabs is a paid site that performs research-based quality checks of various vitamins and supplements, often by brand.

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