Melatonin, Your Thyroid, and Hormones


Melatonin has traditionally been known as a treatment for jet lag and insomnia. The integrative medical world increasingly recommends it for women with breast cancer, and for fibromyalgia and chronic fatigue symptom. But melatonin is gaining greater interest for its ability to affect your thyroid and hormones. 

Melatonin is a hormone itself, produced by the pineal gland, which is a tiny gland located in the brain.

The pineal gland is considered the master controller of our body's clock, including our day-to-day circadian clock that tells us when to sleep and when to wake, and the longer-term biological clock that dictates major hormonal milestones, such as when we enter puberty and menopause.

The pineal gland controls circadian rhythms by releasing melatonin, a hormone produced primarily at night. Melatonin synthesis and release is primarily stimulated by darkness.

Based on its role in circadian rhythm and sleep, melatonin has become well known as a helpful sleep aid, as a treatment to help prevent jet lag and reset the body clock to a new time zone, and for night shift workers who have difficulty sleeping.

It was as a sleep aid that I first started using melatonin nightly when I was in perimenopause. I had been waking up more frequently, and often unable to fall back asleep. Then, when I woke in the morning, I felt fuzzy-brained and tired.

I started taking a low dose of melatonin (3 mg), which I took around 11 p.m., about an hour before I usually fell asleep. After a week, I noticed that I woke less frequently, and when I did, I was able to turn over and fall back asleep easily. Even better, I was waking up in the morning feeling refreshed and energetic, in a great mood.

Even more surprising, I was actually waking up a few minutes before my alarm. (This is definitely not characteristic, as I typically was one of those people who hit the snooze bar multiple times, and only then begrudgingly dragged myself grumpily out of bed. So waking before the alarm, feeling great, was quite uncommon!)

At the time I started the melatonin, I was also well into my perimenopause. I had erratic periods for two years, and it had been five months since my last menstrual period. I had weathered a period of hot flashes using a supplement called Royal Maca, and the hot flashes were gone. I'd seen my physician, who found that I had extremely high FSH and LH levels—markers that can confirm menopause in a woman who isn't having any more periods—and my estrogen and progesterone levels were low. So my doctor and I both assumed that I was in menopause—all I needed was to go the full 12 months without a period, and it would be official. And so what happened next surprised me.

About two months after I started the melatonin, my periods returned. And when they came back, they were very normal. They weren't unusually heavy, as they had been before. The color was normal and perhaps most surprising of all, they started coming regularly every 28 days, which hadn't happened for several years.

I didn't immediately connect the melatonin with the return of a normal menstrual cycle. But with nothing else changed in my regimen, I had to wonder if normalized menstrual cycles in perimenopausal/menopausal women was a known side effect of melatonin. I delved into the research. And that's when I discovered Dr. Walter Pierpaoli, and his fascinating and groundbreaking research on melatonin.

Melatonin and Our Hormones

Italian physician Walter Pierpaoli, MD, created a sensation back in 1996 with the worldwide release of his book, The Melatonin Miracle: Nature's Age-Reversing, Disease-Fighting, Sex-Enhancing Hormone.

The book was a bestseller, and Dr. Pierpaoli's Melatonin Miracle introduced Americans to melatonin, which had just become available over the counter in the U.S. a few years earlier, and its roles as a sleep aid, jet lag remedy, immune enhancer, and potential antioxidant cancer fighter.

But the book was not a one-time effort by Dr. Pierpaoli. For decades, he has been researching and studying melatonin and its effects.

After reading Dr. Pierpaoli's book, I also read a research journal he contributed to, the December 2005 Annals of the The New York Academy of Sciences, which was titled Reversal of Aging: Resetting the Pineal Clock. This edition of the Annals featured numerous scholarly articles and research findings related to melatonin, including several reports from Dr. Pierpaoli. I also had the pleasure to speak with Dr. Pierpaoli personally, to learn more about his ideas about melatonin and reproductive and thyroid hormones.

I learned that many researchers consider melatonin much more than a hormonal sleep aid. Rather, they consider melatonin to be more of a chemical mediator that operates in ways we don't completely understand, but that Dr. Pierpaoli and others are extensively studying.

What Dr. Pierpaoli explains in his book and research findings is that the pineal gland produces less and less melatonin as we age, but if melatonin supplements are taken when melatonin levels are naturally declining, some of the effects of aging may be slowed, stopped, or even, says Dr. Pierpaoli, reversed. Dr. Pierpaoli also believes that melatonin can re-synchronize not only the circadian rhythms of the wake-sleep cycles but the endocrine system overall.

Dr. Pierpaoli claims that providing supplemental melatonin, in a dose of 3 mg nightly, allows the pineal gland to "rest" so to speak, and protects the pineal gland from aging, which then slows down the aging process for other glands and organs. It's a controversial theory, but Dr. Pierpaoli and others have conducted some intriguing studies that suggest he is on to something.

In his writings, Dr. Pierpaoli describes animal studies that found that older animals treated with melatonin returned to normal daily cycling of thyroid hormones. Mice who were 24 months old and treated with melatonin, 24 months is the mouse equivalent of 75 years old for humans, had ovaries that were double the size of untreated mice, suggesting more youthful sexual function. Dr. Pierpaoli also transplanted the pineal glands of aging mice into young mice, and vice versa. The young mice with the old pineal glands developed all sorts of ailments associated with aging, became less vigorous and fertile, and died far younger than normal. The old mice with the young pineal glands regrew hair, gained energy, developed a renewed sex drive, and live, on average so long that if they were people, they'd have been energetic, active, healthy and sexually active well past 100 years of age.

But what explained my own surprising return of normal menstrual cycles was an Italian study conducted by Dr. Pierpaoli that looked at perimenopausal and menopausal women age 42 to 62, evaluating the effects of a daily dose of 3 mg of synthetic melatonin over six months. That study found that the melatonin increased estrogen levels and improved thyroid function. The women under 50 using melatonin also had reduced luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels as a result of the melatonin. In some of the younger women, normal menstrual cycles were restored. And surprisingly, a number of women who were already postmenopausal even returned to normal menstrual cycles. Basically, according to Dr. Pierpaoli and his fellow researchers, low-dose melatonin was delaying—or in some cases, apparently reversing—characteristic endocrine changes that occur during menopause.

With regard to the thyroid, the melatonin didn't appear to change the TSH levels but helped facilitate conversion of T4 to T3, resulting in increased T3 levels in the study group.

A remarkable 96 percent of women in the study who had taken melatonin also reported the total disappearance of morning depression, a symptom that is common in perimenopausal and menopausal women. The women also had fewer complaints about hot flashes, fewer heart palpitations, and better quality and duration of sleep.

While this was not a large study, it was rigorously conducted, and suggests that melatonin may play a key role in hormonal regulation for perimenopausal and menopausal women, and perhaps even more so for those with thyroid imbalances.

Dr. Pierpaoli feels that the drop in melatonin that takes place in a woman's forties may be the hormonal signal that tells the body to begin the perimenopausal transition. We know that in women from 40 to 44, melatonin typically declines substantially. Interestingly, this is the point that is often the beginning of perimenopause. The next big significant point of melatonin decline is from 50 to 54 years, around the point when the menstrual period finally stops for good in most women.

Dr. Pierpaoli's intriguing theory gained support with the findings of a 2008 study reported on in the journal Menopause. That study found that the pineal gland, through melatonin, is involved in the mechanisms that regulate the onset of menopause, and by maintaining higher levels of melatonin, the onset of menopause can be delayed.

Dr. Pierpaoli is, without a question, a zealous advocate for melatonin. The doctor himself is a good advertisement for his anti-aging approach, over 80, energetic, and keeping up a rigorous schedule of activities, research, speaking, writing, and traveling around the world. Dr. Pierpaoli said that if he could go back in time knowing what he knows, he would have started taking melatonin at around age 30.

Dr. Pierpaoli maintains that melatonin acts like a hormonal adaptogen, helping to moderate adrenal, thyroid and reproductive hormones, and maintaining the day-night, monthly, seasonal and lifetime cyclicity of hormones. Dr. Pierpaoli also believes that melatonin increases the density of estrogen receptors in target tissues like the breasts, uterus, and ovaries, and improves their sensitivity.

Some of the other effects of melatonin reported by Dr. Pierpaoli include:

  • helps to balance cortisol levels
  • prevents atrophy of the ovaries, vagina, and uterus
  • extends fertility
  • raises HDL ("good") cholesterol
  • lowers blood pressure

Says Dr. Pierpaoli:

Melatonin is not a hormone itself, but truly a "queen of all hormones," which monitors and directs the whole "hormonal orchestra."

Other Doctors on Melatonin

Dr. Pierpaoli is not the only advocate for melatonin. Thyroid and hormone expert David Brownstein, MD, recommends feels that melatonin is "incredibly safe," for most patients. Says Dr. Brownstein:

Low dose melatonin can be an incredibly helpful part of hormone balancing. Not only is it useful for sleep, but it's also useful for helping the other hormones, and in particular, improved T4 to T3 conversion.

Dr. Jacob Teitelbaum, who works with chronic fatigue syndrome, fibromyalgia and thyroid patients, feels that the effectiveness of melatonin may stem from its ability to promote quality sleep. Says Dr. Teitelbaum:

What happens is when you don't have sleep, you're suppressing the whole system. Getting proper sleep is restoring hypothalamic function. And the melatonin is, at minimum, helping ensure better quality of sleep. And in addition, in the entire hormone system, the pineal can be viewed as the leader of the whole orchestra. If it's sluggish, the rest of the hormonal system can be sluggish.

Supplementing with Melatonin

How do you supplement with melatonin?

Dr. Pierpaoli's recommendation is to take 3 mg of time-released melatonin, at 11 p.m. or an hour before you go to sleep, whichever is earlier. This allows you to have a "melatonin surge" at the time the body would naturally produce it.

The main side effects in the literature from low-dose melatonin appears to be some morning grogginess, vivid dreams, and nightmares, or a mild headache after use in a small percentage of users. This is a sign that you may want to drop back to a lower dose.

According to hormone and thyroid expert Richard Shames, MD:

You might want to start out with 3 mg, then see if you can get just as good a benefit from going to 2 mg, and then possibly to 1 mg. My general opinion is that a 1 mg dose is not likely to cause headache and depression as a side effect.

There really are no published long-term studies evaluating the data of low-dose melatonin. But all the doctors I've spoken with, many who use low-dose melatonin themselves and recommend it to patients, feel that based on the results of shorter-term studies, we are not likely to discover any problems with longer-term use of low-dose melatonin. Melatonin should not, however, be used by women who are pregnant or lactating.

If you're interested in supplementing with melatonin, after you speak with your physician, choose your brand carefully. You want to make sure you are getting a pure, pharmaceutical grade melatonin, and experts suggest that you use only synthetic melatonin and not melatonin derived from animals.

You'll sometimes hear that melatonin is not recommended for people with autoimmune disease, and for those women who have thyroid problems due to autoimmune Hashimoto's or Graves' disease, this may seem problematic. It's still a controversial issue. But I asked Dr. Pierpaoli about this, and he said that there was one isolated case where melatonin was linked to autoimmune hepatitis. He said that the concerns are unfounded, that the melatonin appears to help the immune system function properly, not over function, as detractors suggest. Dr. Pierpaoli - along with other doctors I spoke with—feel that melatonin is helpful for autoimmune diseases. he explained why in an interview he gave to International Anti-aging Systems, a UK-based pharmacy:

As for autoimmunity, melatonin must be used in autoimmune diseases simply because it will restore a normal immune reaction and the capacity of the immune system to recognize "self" antigens. We have observed complete recovery! The etiology of all autoimmune diseases affecting the skin, the glands, the blood and any other tissue is based on congenital or acquired inability to recognize our own body tissues and thus to mount an autoimmune reaction. Aging itself is largely a hidden, latent and insidious autoimmune process leading to vasculitis (sclerosis of vessels), autoantibodies and cancer. Our work of 40 years has led to the demonstration that immunity is totally under hormonal control. Melatonin will not increase the synthesis of aggressive autoantibodies, on the contrary it will progressively lead to healing of the basic hormonal derangements underlying and initiating the autoimmune process.


Díaz, Beatriz López; Llaneza, Plácido Coto. "Endocrine regulation of the course of menopause by oral melatonin: first case report." Menopause. 15(2):388-392, March/April 2008.

Parry, Barbara, et. al. "Increased Melatonin and Delayed Offset in Menopausal Depression: Role of Years Past Menopause, Follicle-Stimulating Hormone, Sleep End Time, and Body Mass Index" The Journal of Clinical Endocrinology & Metabolism. Published Online: July 02, 2013 Online

Pierpaoli, Walter "Reversal of Aging: Resetting the Pineal Clock." December 2005, Wiley-Blackwell. Online

Toffol, Elena et. al. "Melatonin in perimenopausal and postmenopausal women: associations with mood, sleep, climacteric symptoms, and quality of life," Menopause. May 2014 - Volume 21 - Issue 5 - p 493-500