# Melatonin Category: Hormones Or pineal hormone: the pineal gland in the brain responds to an absence of light (or to any stress which increases the adrenalin systems) by secreting a hormone called melatonin, which lightens the skin, makes the brain sluggish, turns off thyroid and progesterone production… 9 passages · 1 author · 1997–2018 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md) Canonical page: https://bioenergeticoracle.com/concepts/melatonin ## Synthesis **Melatonin** is the *pineal hormone* whose secretion Ray Peat characterized as a primary endocrine signal of darkness and stress, fundamentally acting to induce a winter-like, sluggish metabolic state. [Source 3, 9] Peat argued that its production is triggered not simply by an absence of light, but by the **adrenergic nervous stimulation** that increases during the stress of darkness, driving the conversion of serotonin into melatonin within the pineal gland. [Source 2, 5] He consistently maintained that melatonin suppresses **thyroid** and **progesterone** production, shrinks the sex organs and the **thymus gland**, and increases estrogen, thereby damaging immunity and fertility. [Source 3, 6, 9] Peat identified a crucial protective function for melatonin as an *antidote to serotonin*, a substance he viewed as a central mediator of inflammation and stress damage. [Source 5, 6] He explained that the adrenergic stress response activates enzymes that convert serotonin into melatonin, and that this same enzymatic activity appears in inflamed joint tissue and breast cancer, suggesting that melatonin production is a detoxifying response to pathological serotonin accumulation. [Source 6] In a fatigued, de-energized brain state, Peat noted that melatonin can be effective at turning off a vicious cycle involving **nitric oxide** and acetylcholine, thereby protecting against excitatory damage. [Source 4, 7] He considered melatonin much safer than serotonin itself, but emphasized that its presence is evidence of an underlying stress response. [Source 5, 6] Regarding supplementation, Peat drew a sharp distinction between physiological and pharmacological doses. He cited research indicating that a true physiological dose is equivalent to roughly 5 micrograms for an average adult, and acknowledged that an amount much smaller than a milligram can induce sleep. [Source 2, 7] However, he expressed serious doubt about the safety of larger amounts, noting that animal studies showed melatonin could lower both progesterone and thyroid while increasing estrogen, and that its effects on the immune system and tumor growth are dose-dependent and sometimes contradictory. [Source 2, 4, 6] He observed that while high-dose melatonin was used in experiments as an antioxidant protecting against gamma rays, the long-term consequences of such doses could include the involution of the thymus and reproductive systems, mirroring the effects of winter. [Source 7] Peat extensively documented melatonin's role as a *disease-promoting agent* in chronic inflammatory conditions, particularly **rheumatoid arthritis**. [Source 1, 2, 8] He cited studies showing that nocturnal plasma melatonin is higher in RA patients than in healthy controls, that melatonin is present in their synovial fluid, and that synovial macrophages express specific melatonin receptors, leading to enhanced inflammatory cytokine production. [Source 1] He highlighted the circadian opposition between melatonin and cortisol, where the early morning peak of melatonin coincides with the lowest cortisol levels and the highest pro-inflammatory Th1-type cytokine activity, perpetuating the clinical symptoms of the disease. [Source 8] This pro-inflammatory effect, observed at physiological amounts, reinforced his view that melatonin is fundamentally a hormone of the *winter sickness*, with reduced light exposure driving higher and more prolonged serum concentrations that disturb immune function. [Source 4, 8] ## People also ask ### How does melatonin suppress thyroid function according to Peat? Peat argued that melatonin directly suppresses thyroid and progesterone production while increasing estrogen, creating a sluggish metabolic state he likened to a winter-like physiology. ### Why did Peat consider melatonin a protective response despite its negative effects? Peat described melatonin as an antidote to serotonin, produced when adrenergic stress activates enzymes that convert harmful serotonin into melatonin, thereby detoxifying a central mediator of inflammation. ### What dose of melatonin did Peat consider truly physiological? Peat cited research indicating a physiological dose is roughly 5 micrograms for an average adult, and he expressed serious doubt about the safety of larger, pharmacological amounts. ## Related concepts - [Albumin](https://bioenergeticoracle.com/md/concepts/albumin/index.md) - [Anemia](https://bioenergeticoracle.com/md/concepts/anemia/index.md) - [Dehydroepiandrosterone (DHEA)](https://bioenergeticoracle.com/md/concepts/dehydroepiandrosterone-dhea/index.md) - [Estriol](https://bioenergeticoracle.com/md/concepts/estriol/index.md) - [Estrogen](https://bioenergeticoracle.com/md/concepts/estrogen/index.md) - [Mitochondria](https://bioenergeticoracle.com/md/concepts/mitochondria/index.md) ## Cited passages Passage numbers match the `[Source N]` markers in the synthesis above. ### Source 1 — Ray Peat Email Advice Depository — Post 473 Ray Peat · Email · Mar 18, 2018 > ### Reference 49 > > **Ray Peat:** **Ann N Y Acad Sci.** 2002 Jun;966:271-5. **Melatonin in rheumatoid arthritis: synovial macrophages show melatonin receptors.** Maestroni GJ(1), Sulli A, Pizzorni C, Villaggio B, Cutolo M. (1)Centre for Experimental Pathology, Istituto Cantonale di Patologia, Locarno, Switzerland. [georges.maestroni@ti.ch](mailto:georges.maestroni@ti.ch) The pineal neurohormone melatonin is widely recognized as exerting important immunoenhancing effects that act on specific receptors in immunocompetent cells. This action results in stimulation of cytokine production in lymphocytes and macrophages. Here we report that the nocturnal plasma concentration of melatonin in rheumatoid arthritis (RA) patients is higher than in healthy controls. Furthermore, melatonin is present in the synovial fluid of RA patients and synovial macrophages express a specific binding site. We suggest that melatonin may exert a disease-promoting role in RA. --- ### Source 2 — Ray Peat Email Advice Depository — Post 473 Ray Peat · Email · Mar 18, 2018 > ## Thread 2 > > **Question:** I've been researching melatonin and came across a lot of conflicting information. I saw some of your older critiques (lowering thyroid, shrinking thymus) and more recent praises for melatonin (opposing serotonin), so I'm wondering, what is your current position on it? Is it safe to supplement if it helps the person sleep better? Also intriguing are the many studies showing that non-ionizing radiation blocks production of melatonin. I wonder if that is a good or bad sign? > > **Ray Peat:** It’s produced during the stress of darkness, by adrenergic nervous stimulation, and I think one of its functions is to neutralize serotonin, which could be an important antistress function. An amount much smaller than a milligram can bring on sleep, but I doubt the safety of larger amounts. Here are some articles about its involvement in inflammation: [references] ### Source 3 — Glossary Ray Peat · Glossary > Melatonin > > Or pineal hormone: the pineal gland in the brain responds to an absence of light (or to any stress which increases the adrenalin systems) by secreting a hormone called melatonin, which lightens the skin, makes the brain sluggish, turns off thyroid and progesterone production, and suppresses immunity and fertility. ### Source 4 — Ask the Herb Doctor: Mitochondria, GABA, Herbs, and More Ray Peat · Interview · Apr 15, 2016 · http://l-i-g-h-t.com/files/herb-doctors-mitochondria-gaba-and-more.mp4 > ## Melatonin and Seasonality > > **Sarah Murray:** So in different parts of the world, like Hawaii near the equator, seasonal changes don't exist. > > **Ray Peat:** Right, you don't have the winter sickness or winter immune disturbance. > > **Andrew Murray:** I read conflicting information on PubMed. Some said melatonin suppresses tumor aerobic metabolism (the Warburg effect), and others said it was pro-cancerous. > > **Ray Peat:** Some of that varies with the variety of mouse used. Sometimes it decreases tumors, sometimes it increases them. The effect on the immune system partly depends on the dose. At least two groups, one in China and one in Denver, are seeing very clear pro-inflammatory effects from physiological amounts of melatonin. > > **Sarah Murray:** It doesn't seem like you'd want to take something that triggers the wintertime response. > > **Ray Peat:** That's what I've always thought. In our hamster lab, even though the lab was temperature-controlled with a 12-hour light cycle, the hamsters had essentially no thymus gland during the winter. That started me thinking about the potential risk of changing your whole endocrine system by supplementing something like that. ### Source 5 — Ask the Herb Doctor: Hormone Replacement Therapy Ray Peat · Interview · Apr 20, 2013 · http://l-i-g-h-t.com/files/herb-doctors-hormone-replacement-therapy-60-mins.mp4 > ## Melatonin > > **Sarah Murray:** So in a short-term emergency situation, it could be okay, but long-term it's going to have negative side effects. > > **Ray Peat:** Yeah, that depends on the person, but it's much safer than serotonin. ### Source 6 — Ask the Herb Doctor: Hormone Replacement Therapy Ray Peat · Interview · Apr 20, 2013 · http://l-i-g-h-t.com/files/herb-doctors-hormone-replacement-therapy-60-mins.mp4 > ## Melatonin > > **Andrew Murray:** What do you think of melatonin? > > **Ray Peat:** It has its own endocrine problems. It can disturb your progesterone and thyroid production if you take a lot of it. But its function seems to be as a way of detoxifying serotonin. The trigger that turns the conversion in the pineal gland of serotonin into melatonin is the adrenergic stress-related nerves. During the night, your stress increases from the lack of light, and this adrenergic system causes the pineal to convert serotonin to melatonin. In general, melatonin is functioning as an antidote to serotonin. Biologically, it's evidence that you're responding to stress with a detoxifying process. The enzymes that exist in the pineal that are activated by the stress can also be found in inflamed joint tissue and in breast cancer. Serotonin is involved in the pathology of both of those situations. If our enzymes could turn it more quickly into melatonin, there would be less of a serotonin problem. > > **Sarah Murray:** But when people actually take melatonin supplements? > > **Ray Peat:** It's probably protecting against the circulating serotonin. But in itself, in an otherwise healthy person, animal studies showed it was capable of lowering both progesterone and thyroid while increasing estrogen. ### Source 7 — Ask the Herb Doctor: Mitochondria, GABA, Herbs, and More Ray Peat · Interview · Apr 15, 2016 · http://l-i-g-h-t.com/files/herb-doctors-mitochondria-gaba-and-more.mp4 > ## Melatonin and Seasonality > > **Andrew Murray:** Let's move on to melatonin. Advertising is very pro-sleeping and relaxing. It is naturally produced and found in foods. What is your impression of melatonin? > > **Ray Peat:** The good side is that in the fatigued state of the brain—the excitatory, de-energized condition—nitric oxide rises and starts a vicious circle where it activates acetylcholine, which activates nitric oxide synthesis. This can keep you awake. Melatonin is effective at turning off that cycle. So when your brain is in a bad fatigue state, melatonin can protect it by lowering nitric oxide and excitation. > > **Sarah Murray:** Would that be in a small dose? > > **Ray Peat:** Yes. One publication refers to the physiological dose as equivalent to 5 micrograms per body in an average-sized adult. Others have measured it as up to 2 or 3 milligrams in the whole body. When a person takes 10 milligrams, it will put them to sleep, but it is probably doing lots of other things. In antioxidant or radiation protection experiments, they've used a thousand or maybe a million times the physiological concentration. It can do amazing things like protect against gamma rays, but the outcome might have unexpected consequences. In the late 1990s, when the material became cheap, studies claimed it was anti-cancer, anti-stress, and anti-inflammatory. But when I was in graduate school, it was known that pineal extract had specific effects that imitated nighttime and winter. In the winter, the reproductive systems of animals—fish, turtles, lizards, rats, sheep—shrink. The thymus gland also regresses, which affects the immune system. This involution of reproductive glands and the thymus has behavioral consequences, like Seasonal Affective Disorder (SAD), depression, and weight gain. Melatonin is the main thing that causes this involution. ### Source 8 — Ray Peat Email Advice Depository — Post 473 Ray Peat · Email · Mar 18, 2018 > ### Reference 35 > > **Ray Peat:** **Autoimmun Rev.** 2005 Nov;4(8):497-502. Epub 2005 Jun 13. **Altered circadian rhythms in rheumatoid arthritis patients play a role in the disease's symptoms.** Cutolo M(1), Villaggio B, Otsa K, Aakre O, Sulli A, Seriolo B. (1)Research Laboratory and Division of Rheumatology, Department of Immunology and Endocrinology, University of Genova, Italy Viale Benedetto XV, 16132 Genova-I, Italy. [mcutolo@unige.it](mailto:mcutolo@unige.it) The circadian changes in the metabolism or nocturnal secretion of endogenous corticosteroids (reduction) observed in rheumatoid arthritis (RA) patients are responsible, in part, for the time-dependent changes that are observed in the inflammatory response and related early morning clinical symptoms of the disease. Melatonin (MLT), another circadian nocturnal hormone that is the secretory product of the pineal gland, has been implicated in the time-dependent RA inflammatory reaction with effects that are opposite to those of corticosteroids. As a consequence, altered functioning of the HPA axis (early morning reduced corticosteroid production) and of the pineal gland (night increased MLT production) found in RA patients, seem to be important factors in the appearance and perpetuation of the clinical circadian symptoms of the disease. Consistently, human proinflammatory Th1-type cytokine production (related to MLT stimulation) exhibits a diurnal rhythmicity with peak levels during the night and early morning, at a time when plasma cortisol (inducing the Th2-type cytokine production) is lowest and MLT is highest. Reduced daily light exposure as observed in northern Europe (Estonia), at least during the winter, might explain the higher and more prolonged serum MLT concentrations that were observed in northern RA patients, as well as some epidemiological features versus southern Europe patients. --- ### Source 9 — From PMS to Menopause: Female Hormones in Context Ray Peat · Book · 1997 > **Ray Peat:** For example, it can cure depression, improve immunity, stimulate our metabolism while decreasing food craving, and increase our intelligence. Although exposure to sun does contribute to aging of the skin, people who spend years working outdoors have a reduced incidence of cancer of internal organs. For many years, it has been known that the death rate increases during the winter months and also increases at night (winter or summer). Most deaths occur just before dawn when the body is in its least efficient state. It is just in the last few decades that we have been learning the reasons for this beneficial effect of light. It turns out that daylight stimulates our ability to use oxygen for energy production, and protects our tissues from some of the free-radical toxins that are produced by normal metabolism, by stress, or by radiation. While ultraviolet light, and even blue light, tend to suppress our cells' ability to produce energy, those types of light penetrate only a short distance into living tissue, and so it is mainly the skin which is damaged by too much sunlight. Since blood does circulate in the layers of skin which receive ultraviolet rays, prolonged sun exposure can damage the immune system by injuring white blood cells, but usually the stimulating effect of the other types of light that penetrate more deeply offset this effect on the immune system. Many health food stores are now selling melatonin, to induce sleep and "prevent cancer." They have taken some information out of context, and don't realize how dangerous melatonin is. It makes the brain sluggish, causes the sex organs to shrink, and damages immunity by shrinking the thymus gland. It suppresses thyroid and progesterone, and increases estrogen. It is the hormone of darkness and winter, and is produced in the pineal gland by any stress which increases adrenalin. Adequate sunlight suppresses the formation of melatonin. _Generated 2026-07-20 from the Bioenergetic Oracle corpus._