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Melatonin

Melatonin

hormone support· Recovery
A-Tier · Strong Evidence62 citations
Found in 22 products
Quick Answer:The clinical dose of Melatonin is 0.3-5mg. Melatonin is a neurohormone derived from tryptophan, primarily synthesized in the pineal gland.Found in 22 products on SuppVault.
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Products Containing Melatonin
22 products contain Melatonin.
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Mechanism of Action

Biosynthesis and Regulation

Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine synthesized from the essential amino acid L-tryptophan. The pathway proceeds through several enzymatic steps: L-tryptophan is hydroxylated by tryptophan hydroxylase (TPH) to form 5-hydroxytryptophan (5-HTP). 5-HTP is then decarboxylated by aromatic L-amino acid decarboxylase (AADC) to produce serotonin (5-hydroxytryptamine). The subsequent two steps are unique to melatonin synthesis and are primarily localized to the pineal gland. Serotonin is N-acetylated by arylalkylamine N-acetyltransferase (AANAT; EC 2.3.1.87), the rate-limiting enzyme in the pathway, to form N-acetylserotonin. Finally, N-acetylserotonin is O-methylated by acetylserotonin O-methyltransferase (ASMT), also known as hydroxyindole-O-methyltransferase (HIOMT; EC 2.1.1.4), to yield melatonin.

The activity of AANAT is under tight circadian control, driven by environmental light cues. Light information is transmitted from intrinsically photosensitive retinal ganglion cells (ipRGCs) via the retinohypothalamic tract (RHT) to the suprachiasmatic nucleus (SCN). The SCN projects to the paraventricular nucleus (PVN) of the hypothalamus, which in turn sends signals down to the superior cervical ganglion (SCG). Postganglionic sympathetic fibers from the SCG innervate the pineal gland. During darkness, norepinephrine (NE) is released from these fibers, binding to β1- and α1-adrenergic receptors on pinealocytes. This activates a Gs-protein coupled signaling cascade, leading to increased intracellular cyclic AMP (cAMP), which phosphorylates and activates AANAT, dramatically increasing melatonin synthesis and secretion. Conversely, light exposure suppresses NE release, leading to AANAT dephosphorylation and inactivation, thus inhibiting melatonin production.

Receptor Signaling

Melatonin exerts its physiological effects primarily through two high-affinity G-protein coupled receptors (GPCRs): Melatonin Receptor 1 (MT1) and Melatonin Receptor 2 (MT2). Both receptors are coupled to inhibitory G-proteins of the Gαi/o family. They are densely expressed in the SCN, retina, and other central and peripheral tissues.

- MT1 Receptor (MTNR1A): Activation of MT1 receptors leads to the inhibition of adenylyl cyclase, resulting in a decrease in intracellular cAMP levels. This signaling cascade ultimately causes hyperpolarization and inhibition of neuronal firing in the SCN. This 'braking' effect on SCN activity is thought to be the primary mechanism by which melatonin promotes sleep onset and reduces sleep latency.

- MT2 Receptor (MTNR1B): MT2 receptor activation also inhibits adenylyl cyclase but is more specifically linked to the phase-shifting properties of melatonin. It modulates the timing of the circadian clock, helping to entrain it to the 24-hour light-dark cycle. This is crucial for adapting to changes in time zones (jet lag) or work schedules. MT2 signaling can also inhibit cGMP pathways and influence phospholipase C activity.

Pharmacokinetics

Upon oral administration, melatonin is rapidly absorbed, with time to maximum plasma concentration (Tmax) typically occurring within 30 to 60 minutes. However, it undergoes extensive first-pass metabolism in the liver, primarily via hydroxylation by CYP1A2 and CYP2C19 enzymes, followed by conjugation with sulfate or glucuronic acid. This results in low and highly variable oral bioavailability, estimated to be between 3% and 33%. The plasma half-life (t1/2) of exogenous melatonin is short, generally ranging from 30 to 60 minutes. This pharmacokinetic profile explains why standard-release melatonin is effective for initiating sleep but may be less effective for maintaining sleep throughout the night, leading to the development of extended-release formulations.

Works Best With
Magnesium (Glycinate)
Magnesium supports relaxation and nervous system function by acting as a GABA receptor agonist and NMDA receptor antagonist. This complements melatonin's chronobiotic action.
L-Theanine
An amino acid from green tea that promotes relaxation without sedation by increasing alpha brain waves and modulating neurotransmitters like GABA and serotonin. It can help quiet the mind before melatonin's sleep signal takes effect.
GABA (Gamma-Aminobutyric Acid)
The primary inhibitory neurotransmitter in the brain. Direct supplementation aims to promote calmness and reduce neuronal excitability, though its ability to cross the blood-brain barrier is debated.
Questions About Melatonin
What is melatonin? +
Melatonin is a natural hormone produced by the pineal gland in your brain, primarily at night. Its main function is to regulate the body's sleep-wake cycle, also known as the circadian rhythm. As a supplement, it is used to help improve sleep, combat jet lag, and adjust sleep schedules.
How does melatonin work? +
Melatonin works by binding to MT1 and MT2 receptors in the brain's suprachiasmatic nucleus (SCN), which acts as the body's master clock. This binding signals to the body that it is nighttime, which helps reduce the time it takes to fall asleep (sleep latency) and can help shift the timing of the sleep cycle.
What is the best dose of melatonin? +
The most effective dose of melatonin ranges from 300 micrograms (0.3 mg) to 5 mg. It is not dose-dependent, meaning taking more than 5 mg is unlikely to help you fall asleep faster. It's best to start with a low dose and only increase if necessary.
When is the best time to take melatonin? +
The best time to take melatonin is approximately 30 to 60 minutes before your desired bedtime. This allows enough time for it to be absorbed and begin to exert its effects. Consistent timing is key to helping regulate your sleep cycle.
What are the side effects of melatonin? +
Melatonin is generally well-tolerated. The most common side effects are mild and can include dizziness, headache, or next-day grogginess, especially with higher doses. These can often be avoided by taking the lowest effective dose.
Is melatonin addictive? +
No, melatonin is considered non-addictive. Unlike many prescription sleep medications, it does not cause physical dependence or withdrawal symptoms. The body does not build a tolerance to it in the same way.
Do I need to cycle melatonin? +
There is no evidence to suggest that melatonin needs to be cycled. It can be used nightly for extended periods. However, if your sleep issues resolve, you can stop taking it or use it only as needed.
What is the best form of melatonin? +
The best form depends on your needs. Standard, immediate-release tablets are effective for difficulty falling asleep. Extended-release versions are designed for those who have trouble staying asleep. The evidence for the superiority of liquid or gummy forms is limited.
Who should take melatonin? +
Melatonin is suitable for adults experiencing insomnia, jet lag, or disruptions from shift work. It can also be beneficial for older individuals, as natural melatonin production tends to decrease with age. Athletes may also use it to enhance recovery through better sleep.
Who should not take melatonin? +
You should consult a doctor before taking melatonin if you are pregnant, breastfeeding, have an autoimmune disease, or are on certain medications like blood thinners or immunosuppressants. It is generally not recommended for children unless advised by a pediatrician.
Can I stack melatonin with other supplements? +
Yes, melatonin stacks well with other supplements that promote relaxation. Common synergistic ingredients include magnesium (especially glycinate), L-theanine, and apigenin (from chamomile), which work through different pathways to calm the nervous system and prepare the body for sleep.
Is long-term use of melatonin safe? +
Current research suggests that long-term use of melatonin at appropriate doses is safe for most adults. It has been used in studies lasting for months or even years without significant adverse effects. As always, it's best to discuss long-term use with your healthcare provider.
Can I get melatonin from food? +
Yes, melatonin is found in small amounts in some foods like tart cherries, walnuts, pistachios, and milk. However, the amounts are typically far too low to have the same therapeutic effect as a supplement. You would need to consume very large quantities of these foods to get a clinical dose.
Is there a difference between branded and generic melatonin? +
Generally, there is no significant difference in the melatonin molecule itself between branded and generic versions. The key is to choose a reputable brand that uses third-party testing to verify the purity and dosage listed on the label. Product quality and accuracy can vary between manufacturers.
Do I need a loading phase for melatonin? +
No, a loading phase is not necessary for melatonin. It works on an acute basis, meaning you will feel its effects from the very first dose. The goal is to take it when you need it to help regulate your sleep for that night.
Does melatonin interact with medications? +
Yes, melatonin can interact with several types of medications. These include anticoagulants (blood thinners), immunosuppressants, diabetes drugs, and blood pressure medications. It is crucial to consult your doctor or pharmacist before taking melatonin if you are on any prescription medicine.
Will melatonin make me feel groggy in the morning? +
Morning grogginess is not a common side effect but can occur, particularly if the dose is too high or taken too late at night. If you experience this, try reducing your dose or taking it slightly earlier in the evening. For most people, melatonin leads to feeling more refreshed upon waking.
Research Highlights
Fatemeh G et al., 2022meta-analysis
Effect of melatonin supplementation on sleep quality: a syst
Melatonin supplementation significantly improves sleep quality, particularly in individuals with respiratory diseases, metabolic disorders, and primary sleep disorders.
Pattanittum P et al., 2016meta-analysis
Dietary supplements for dysmenorrhoea.
The Cochrane review found some evidence suggesting melatonin may be effective for reducing pain in dysmenorrhea, though more high-quality research is needed.
Chan V et al., 2022meta-analysis
Efficacy of dietary supplements on improving sleep quality:
This meta-analysis concluded that melatonin was among the dietary supplements with evidence supporting its efficacy for improving sleep quality.
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