Melatonin megadoses?

#388

@Beth With age, body makes less melatonin, which I understand, and to take some melatonin to replace what’s lacking makes sense to me. However, taking anything in great excess makes that lacking chemical a strong medication, the mechanism of action of which is not fully understood as I read about it. So, I asked ChatGPT about possible complications of taking mega doses of Melatonin.

Taking mega doses of melatonin (far beyond the commonly recommended 0.5–5 mg range) on a regular basis can lead to a variety of short- and long-term complications, even though melatonin is generally considered safe in small doses for short-term use. Here’s a breakdown of potential complications:

1. Hormonal Disruption

Melatonin is a hormone, and taking large doses regularly can interfere with your body’s natural hormonal rhythms. This might affect:

  • Reproductive hormones, potentially impacting fertility (especially in women).
  • Puberty onset in adolescents.
  • Menstrual cycle irregularities.

2. Sleep-Wake Cycle Disruption

Ironically, too much melatonin can throw off your circadian rhythm:

  • You may start to feel groggy during the day and wide awake at night.
  • Over time, your natural melatonin production could downregulate, making sleep harder without the supplement.

3. Mood and Cognitive Effects

Excess melatonin might contribute to:

  • Depression or low mood.
  • Brain fog or difficulty concentrating.
  • Increased daytime drowsiness or sluggishness.

4. Drug Interactions & Health Risks

High doses of melatonin can interact with:

  • Blood thinners (e.g., warfarin): increased bleeding risk.
  • Immunosuppressants: may interfere with immune function.
  • Diabetes medications: may affect blood sugar control.
  • Seizure medications: can increase risk of seizures in some people.

5. Headaches, Dizziness, and Nausea

Common side effects at higher doses:

  • Headaches
  • Dizziness
  • Nausea
  • Vivid dreams or nightmares

6. Tolerance and Dependency

While melatonin isn’t typically considered addictive, using large doses frequently can lead to:

  • Psychological dependence (“I can’t sleep without it”).
  • Reduced effectiveness over time (needing more to get the same effect).

It was enough for me not to take mega doses or even take it consistently every night. Logically, I cannot agree with taking anything in great excess.

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#389

Citing ChatGPT without providing sources is not very valuable. I’m not sure the point as backed by science other than fertility and puberty: these are really important ones with many papers on it.

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#390

The problem with the phrase possible complications is that it comes up with masses of things. I have been on over a gram of melatonin a night for over a year and as far as I am concerned I intend to continue with this.

I have been doing a weekly blood panel now for almost 3 years whilst varying at lot of what I do and have identified only positives from Melatonin.

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#391

Melatonin’s role in delaying puberty is part of what it does. It holds back damage to mitochondrial DNA which delays the development clock (in my hypothesis of what the development clock is).

For example where girls have Hypothalamic hamartomata you get a reduction in melatonin and precocious puberty.

That is not a bad side effect of melatonin it is one of its functions in the body. As far as I am concerned aged as I am 65 I don’t expect to go through puberty in reverse as a result of taking melatonin.

In fact because puberty is an interplay between mRNA splicing changes and hormonal changes I think it would be hard to reduce fully even by turning the development clock right back.

Melatonin’s effects on fertility are more complex and it is probably best timed to suit ovulation and protection of both the ovaries and the eggs.

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#392

You are right. I erased links to the papers to make it shorter :grinning: silly me. Melatonin dosing is not well researched unfortunately.

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#393

Just seing this study now, the RRs are crazy good: “melatonin use was associated with a reduced risk of developing AMD (RR, 0.42; 95% CI, 0.28-0.62) […] melatonin was associated with a reduced risk of AMD progression to exudative AMD (RR, 0.44; 95% CI, 0.34-0.56)”.

This paper is cited in: Melatonin protects retinal pigment epithelium cells against ferroptosis in AMD via the PI3K/AKT/MDM2/P53 pathway 2025

And in Melatonin stabilizes atherosclerotic plaques: an association that should be clinically exploited 2024. @A_User, is it clinically relevant?

On AMD and PD:

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#394

Looks like mechanistic speculation, so not at all.

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#395

I wasn’t sure which thread to put this under so l figured this is as good as any.

I have been using high doses of melatonin (100 to 500 mg and more) since September 2024. I have had weird nerve pain problems for at least the last 5 years (mainly sciatic but others too). Anytime l would bend down to pick something up l ran the risk agitating the nerve and it could last 2 to 6 weeks. During the day easily dealt with but at night it would make it almost impossible for me to sleep.

Around December l started noticing my nerves seemed to be becoming more resilient. I pushed it a bit too hard in February 2025 and had a 3 week stint of pain but other than that it seemed to be getting progressively better even now.

I have done exercises in the past and if l pushed a little too much it could cause a flare up.

To be completely upfront, as stated previously l am performing many interventions including rapa and it could be all interventions synergistically or none at all but l attribute these positive effects to the melatonin.

I still have a fair amount of issues that l am trying
to address but to paraphrase Dr. Reiter “melatonin is pretty good”.

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#396

@John_Hemming how do you take 1g of melatonin. I find the powder very bitter and hard to keep up on a daily basis. Even with yogurt it makes the yoghurt bitter.

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#397

I take a lot of pills. 20 60mg pills now 10 12mg and 15 20mg. It was 10x12 10x20 + 10x10 = 1200+120+300=1620mg

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#398

Where from? I’m also in Aus

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#399

I thought you took the powder form…

#400

Rarely. I tried mixed with malt whisky. It put me to sleep.

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#401

Efficacy of a Neuroimmune Therapy Including Pineal Methoxyindoles, Angiotensin 1-7, and Endocannabinoids in Cancer, Autoimmune, and Neurodegenerative Diseases

Weird Italian-Argentinian paper:

Patients and Methods: This study evaluates the safety and efficacy of a neuroimmune regimen comprising melatonin (100 mg/day at night), 5-methoxytryptamine (30 mg in the early afternoon), angiotensin 1– 7 (0.5 mg twice daily), and cannabidiol (20 mg twice daily) in 306 patients with NCDs, including advanced cancer, autoimmune diseases, neurodegenerative disorders, depression, and cardiovascular disease.
Results: The neuroimmune regimen successfully halted cancer progression in 68% of cancer patients, who also reported improvements in mood, sleep, and relief from anxiety, pain, and fatigue. In patients with autoimmune diseases, the treatment effectively controlled the disease process, remarkable in cases of multiple sclerosis. Additionally, positive outcomes were observed in patients with Parkinson’s disease, Alzheimer’s disease, and depression.

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#402

On fertility:

Chinese paper, male mice: Melatonin ameliorates RF-EMR-induced reproductive damage by inhibiting ferroptosis through Nrf2 pathway activation 2025

Iranian preprint, female humans: Melatonin treatment results in progression of endometrial thickness in infertile women in IUI cycle 2025: “In general, administration of melatonin for 4 weeks in infertile women undergoing IUI cycle had beneficial effects on endometrial thickness, which was associated with better pregnancy outcome.”

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Melatonin and Exercise Restore Myogenesis and Mitochondrial Dynamics Deficits
#403

my “lifetime” supply of melatonin arrived lol. 33333 doses according to this, 92 years at the recommended dose.

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#404

Effects of melatonin implants on the rate of pseudopregnancy in high yielding dairy goats 2025

ChatGPT explanation:

  • Pseudopregnancy (PPG) is the accumulation of sterile uterine fluid together with a persistent corpus luteum; it prolongs anoestrus and causes temporary infertility. On commercial dairy farms the condition typically affects 6–30 % of does and may cluster in specific years or management systems
  • A year-long field study on five Portuguese dairy-goat farms (2023-24) shows that giving does one 18-mg slow-release melatonin implant four to six weeks before buck introduction slashed pseudopregnancy (hydrometra) rates from the usual 7–10 % down to <1 %. Compared with natural, untreated cycles the odds of pseudopregnancy fell ~15-fold, and compared with a standard progesterone-CIDR induction protocol they fell ~40-fold. Primiparous does were still the most vulnerable group, but even they benefitted markedly from melatonin. The work suggests that, in high-yielding herds where intensive progesterone programmes are common, swapping those protocols for pre-breeding melatonin could improve fertility, shorten kidding intervals and reduce veterinary interventions.
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#405

It taste terrible lol. I feel like I’ve to force myself.

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#406

I had such a tiny amount I couldn’t taste anything. I dipped a spoon in and then shook off as much as I can. Just a bit of dust stuck to it. Already feel it. I’m unsure how to properly dose this.

#407

I took every melatonin study in this thread and fed it into ChatGPT and got it to spit out a summary of all of them:

:dna: Core Biological Roles of Melatonin

1. Circadian Regulation

  • Melatonin is primarily secreted by the pineal gland and plays a key role in synchronizing circadian rhythms.
  • It follows a light-dependent cycle, peaking at night and signaling darkness to the body, thereby promoting sleep and regulating hormonal cycles (including cortisol and reproductive hormones).

2. Mitochondrial Health & Energy Metabolism

  • Melatonin is synthesized not only in the pineal gland but also in mitochondria.
  • Studies show it enhances mitochondrial function by:
    • Promoting ATP production.
    • Reducing mitochondrial oxidative stress.
    • Improving mitochondrial calcium homeostasis.
  • It can stimulate muscle fiber conversion (from glycolytic to oxidative) in diabetic models—mimicking some effects of endurance exercise.

3. Antioxidant & Free Radical Scavenging

  • Melatonin directly scavenges reactive oxygen and nitrogen species.
  • It also upregulates endogenous antioxidant enzymes (e.g., SOD, glutathione peroxidase).
  • Unique among antioxidants, it crosses the blood-brain barrier and concentrates in mitochondria and nuclei.

:brain: Neuroprotection & Brain Health

4. Alzheimer’s & Parkinson’s Disease

  • Melatonin reduces tau hyperphosphorylation and Aβ accumulation in animal models.
  • Enhances glymphatic clearance of metabolic waste, possibly reducing risk of neurodegeneration.
  • Supports mitochondrial integrity in neurons and may help counter age-related metabolic shifts in brain cells.

5. Cognitive Function & Memory

  • Improves long-term memory formation in rodents via modulation of protein phosphorylation.
  • Enhances glymphatic function post-intracerebral hemorrhage, resulting in improved cognitive recovery.

:person_in_lotus_position: Sleep and Chronobiology

6. Sleep Quality

  • Meta-analyses show optimal efficacy for:
    • 3–4 mg taken ~3 hours before bedtime.
    • Helps reduce sleep onset latency and increase total sleep time.
  • Especially effective in older adults and those with insomnia or circadian rhythm disorders.

7. Jet Lag, Shift Work, and Chronotherapy

  • Well-suited for shifting circadian phase in cases of jet lag and shift work.
  • Has been studied as a tool in chronotherapy to align medication administration with biological rhythms.

:heartbeat: Cardiovascular & Metabolic Health

8. Blood Pressure Regulation

  • Reduces nocturnal blood pressure (more in “non-dippers”), possibly via improved endothelial function and oxidative stress reduction.

9. Glucose Metabolism and Diabesity

  • In diabetic models:
    • Enhances insulin sensitivity.
    • Supports healthy skeletal muscle function.
    • Promotes metabolic reprogramming of muscle and liver.

:eye: Retinal and Ocular Health

10. Age-Related Macular Degeneration (AMD)

  • Protects retinal pigment epithelial (RPE) cells by:
    • Inhibiting necroptosis.
    • Suppressing NLRP3 inflammasome via the SIRT1/Nrf2 pathway.
  • Preserves retinal structure in AMD models.

:microbe: Immune Modulation

11. Dual Immunoregulation

  • Acts as an immune buffer:
    • Stimulates immunity in immunosuppressed states.
    • Suppresses excessive inflammation during cytokine storms.
  • Reduces IL-6 and TNF-α while promoting IL-10 and T-reg activity.
  • Shown to modulate macrophage activity via NF-κB and AA-NAT upregulation.

12. Applications in Autoimmune and Infectious Disease

  • May help in autoimmune diseases and as an adjunct in viral infections (e.g., COVID-19) by dampening hyperinflammation while preserving immune competence.

:dna: Anti-Aging and Lifespan Extension

13. Lifespan Studies

  • Melatonin extended lifespan in several animal models (e.g., flies, mice, aquatic invertebrates), possibly due to its mitochondrial and antioxidant actions.
  • Highlighted in DrugAge as a candidate longevity agent.

14. Aging Phenotypes

  • Maintains mitochondrial and glymphatic function with age.
  • Prevents pathological metabolic reprogramming in aged neurons.

:test_tube: Cancer and Cell Growth

15. Anticancer Activity

  • Shown to inhibit proliferation in some cancer cell lines.
  • May sensitize tumors to chemotherapy while protecting normal cells from side effects (radioprotective and antioxidant roles).

:warning: Safety, Risks, and Considerations

16. Generally Safe — But Not Always Benign

  • Very high doses (up to 200 mg/day) used in research with minimal side effects reported.
  • Most common mild side effects: vivid dreams, morning grogginess, headaches.

17. Rare Case Reports

  • One case report linked melatonin to ventricular arrhythmias (PVCs), which resolved after stopping supplementation — indicates rare individual susceptibility.

18. Hormonal & Developmental Considerations

  • Low melatonin levels in children with hypothalamic hamartomas were linked to precocious puberty, suggesting a role in reproductive timing.

Summary: The Case for Melatonin

Melatonin is a pleiotropic molecule:

  • Antioxidant, immunomodulator, chronobiotic, and neuroprotective agent.
  • It impacts systems far beyond sleep, including metabolism, immunity, cognition, mitochondrial health, and aging.
  • Therapeutically, it is among the most underrated low-toxicity compounds with broad potential — though rare risks exist and personalization is warranted.
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