What is Melatonin and how does it regulate circadian rhythm through MT1/MT2 receptors?

Melatonin (N-acetyl-5-methoxytryptamine) is a lipophilic indoleamine hormone (MW ~232 Da) primarily synthesized in the pineal gland from tryptophan via serotonin, serving as the master regulator of circadian rhythm and sleep-wake cycles. Chemical structure: tryptophan → 5-hydroxytryptophan (5-HTP) → serotonin → N-acetylserotonin (via serotonin N-acetyltransferase, AANAT, the rate-limiting enzyme) → melatonin (via hydroxyindole-O-methyltransferase, HIOMT). Synthesis and secretion follow strict circadian pattern: low during daylight, dramatically rising at night (peak levels 2-4 AM), controlled by suprachiasmatic nucleus (SCN, the master circadian pacemaker in hypothalamus) receiving light/dark information from retinal photoreceptors. Mechanistically: (1) MT1 and MT2 receptor signaling - Melatonin binds two G-protein-coupled receptors (GPCRs): MT1 (MT1R, MTNR1A) and MT2 (MT2R, MTNR1B), both Gi/Go-coupled inhibiting adenylyl cyclase reducing cAMP levels, activating phospholipase C, and modulating ion channels (K+ and Ca2+). MT1 primarily mediates acute sleep-promoting effects and metabolic regulation, while MT2 primarily regulates circadian phase-shifting (the ability to advance or delay circadian clock timing). (2) SCN effects - Melatonin binds MT1/MT2 in SCN providing feedback regulation: 'telling' the SCN it is nighttime, entraining circadian rhythms to environmental light-dark cycles. This explains melatonin's use for jet lag and shift work (exogenous melatonin administration can phase-advance or phase-delay circadian rhythm depending on timing). (3) Sleep promotion - Melatonin reduces core body temperature (heat dissipation promotes sleep onset), reduces alertness and arousal (effects on SCN and other brain regions), and promotes sleep architecture transitions. Unlike sedative-hypnotics (benzodiazepines, Z-drugs) which force sleep through GABA-A receptor modulation often disrupting sleep architecture, melatonin facilitates natural sleep-wake transitions. (4) Antioxidant effects - Beyond receptor-mediated signaling, melatonin is potent direct free radical scavenger (hydroxyl radicals, superoxide, peroxynitrite), lipophilic allowing it to cross membranes and blood-brain barrier scavenging ROS in mitochondria and nucleus, and upregulates antioxidant enzymes (SOD, catalase, glutathione peroxidase). Melatonin's antioxidant capacity exceeds vitamin C and E in some assays. (5) Immune modulation - Melatonin enhances immune function (increased lymphocyte proliferation, cytokine production, NK cell activity) with circadian pattern (immune function peaks at night when melatonin is high). (6) Metabolic effects - Melatonin regulates glucose homeostasis and insulin sensitivity; disrupted melatonin signaling (shift work, chronic insomnia, genetic MT2 variants) associates with increased diabetes risk. Research applications include circadian rhythm research, sleep disorders, jet lag and shift work adaptation, aging (melatonin declines with age), neurodegenerative diseases, antioxidant studies, cancer biology (melatonin has oncostatic properties in some cancers), and metabolic research.

How does melatonin synthesis and secretion follow circadian patterns and what regulates AANAT?

Melatonin synthesis exhibits remarkable circadian rhythmicity controlled by multi-level regulation: (1) SCN master clock - The suprachiasmatic nucleus contains ~20,000 neurons functioning as autonomous circadian oscillators driven by transcription-translation feedback loops of clock genes (CLOCK, BMAL1, PER, CRY). Light entrains SCN via retinohypothalamic tract (RHT): melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) detect environmental light sending glutamate signals to SCN resetting clock gene expression. (2) SCN → Pineal pathway - SCN projects to paraventricular nucleus (PVN) → superior cervical ganglion (SCG) → pineal gland via norepinephrine (NE) release. During darkness, SCN disinhibits this pathway allowing NE secretion; during light, SCN suppresses NE release. (3) AANAT regulation - Serotonin N-acetyltransferase (AANAT) is the rate-limiting enzyme converting serotonin to N-acetylserotonin (the penultimate melatonin precursor). AANAT activity increases 10-100 fold at night via multiple mechanisms: transcriptional upregulation (NE activates β-adrenergic receptors → cAMP → PKA → CREB → AANAT gene transcription), post-translational stabilization (PKA phosphorylates AANAT creating binding site for 14-3-3 proteins which protect AANAT from proteasomal degradation; during day, dephosphorylated AANAT is rapidly degraded with half-life ~3 minutes), and allosteric regulation. This creates switchlike melatonin production: low during day (AANAT unstable, rapidly degraded), high at night (AANAT stable, active). (4) HIOMT - Hydroxyindole-O-methyltransferase (HIOMT) converts N-acetylserotonin to melatonin (adding methyl group from S-adenosylmethionine). HIOMT shows less dramatic circadian variation than AANAT but still contributes to regulation. (5) Melatonin secretion and clearance - Synthesized melatonin immediately diffuses from pineal into blood (no storage vesicles) creating rapid on/off kinetics matching synthesis. Plasma melatonin shows dramatic circadian variation: daytime levels ~5-10 pg/mL, nighttime peak 50-200 pg/mL (10-40 fold increase). Melatonin is rapidly metabolized (plasma half-life ~20-50 minutes) primarily in liver via CYP1A2 to 6-hydroxymelatonin (excreted as 6-sulfatoxymelatonin in urine - measuring urinary 6-sulfatoxymelatonin quantifies integrated melatonin production). (6) Light suppression - Light exposure during subjective night acutely suppresses melatonin synthesis (within 30-60 minutes) via SCN-mediated NE suppression and AANAT destabilization. Blue light (460-480 nm) is most potent due to melanopsin spectral sensitivity. This explains negative effects of nighttime screen exposure on sleep. (7) Age-related changes - Melatonin production declines with aging: childhood shows high levels, adult peak in 20s-30s, progressive decline thereafter. Elderly subjects may have 50-80% reduction in nocturnal melatonin associated with increased sleep disturbances. Pineal calcification and reduced AANAT expression contribute. Research applications: studying circadian clock mechanisms, light entrainment pathways, AANAT regulation as drug target for circadian disorders, and developing melatonin receptor agonists or AANAT activators/inhibitors.

What research applications benefit from melatonin's circadian, sleep, and antioxidant properties?

Melatonin excels in diverse research areas: (1) Circadian rhythm research - Melatonin is gold-standard circadian phase marker (dim light melatonin onset, DLMO, measured via serial blood/saliva sampling under controlled dim light, marks circadian phase). Researchers use melatonin to study circadian disorders (delayed sleep phase syndrome, advanced sleep phase syndrome, non-24-hour sleep-wake disorder in blind individuals, shift work disorder), entrainment mechanisms, and clock gene regulation. Phase-response curves (PRCs) characterize how melatonin administration at different circadian times shifts rhythm (early evening melatonin advances rhythm, early morning delays rhythm). (2) Sleep research - Investigating melatonin's effects on sleep latency (time to fall asleep), total sleep time, sleep efficiency, and sleep architecture (REM vs NREM stages). Insomnia models (primary insomnia, comorbid insomnia with psychiatric/medical conditions, age-related insomnia) test whether melatonin improves sleep outcomes. Unlike benzodiazepines which alter sleep architecture and cause dependence, melatonin promotes natural sleep. Ramelteon and tasimelteon (selective MT1/MT2 agonists) research as sleep medications. (3) Jet lag and shift work research - Jet lag results from circadian misalignment between internal clock and external time zone. Properly timed melatonin administration (typically at destination bedtime) accelerates re-entrainment. Shift work research examines whether melatonin improves sleep during daytime sleep periods and reduces circadian disruption health consequences (metabolic syndrome, cardiovascular disease, cancer). (4) Aging and neurodegeneration - Age-related melatonin decline parallels sleep deterioration and increased oxidative stress. Research investigates whether melatonin supplementation in aged animals improves sleep, cognitive function, and neuroprotection. Alzheimer's disease research: AD patients show disrupted circadian rhythms and reduced melatonin; studies test whether melatonin reduces amyloid-β accumulation (melatonin inhibits Aβ aggregation and fibrillation in vitro), tau phosphorylation, oxidative damage, and cognitive decline. Parkinson's disease research examines melatonin's neuroprotection against dopaminergic neuron loss. (5) Oxidative stress and mitochondrial research - Melatonin's antioxidant properties (direct ROS scavenging, upregulation of antioxidant enzymes) make it valuable in ischemia-reperfusion injury models (stroke, myocardial infarction), neurotoxicity models (MPTP-induced parkinsonism, rotenone, 6-OHDA), radiation protection, and aging research. Melatonin accumulates in mitochondria protecting against mitochondrial oxidative damage and maintaining respiratory chain function. (6) Cancer research - Melatonin shows oncostatic properties in various cancers (breast, prostate, colorectal) through mechanisms including antioxidant effects, pro-apoptotic signaling, anti-angiogenesis, immunomodulation, and receptor-mediated growth inhibition. Circadian disruption (shift work, chronic jet lag) increases cancer risk; research investigates whether melatonin supplementation provides protection. Melatonin also reduces chemotherapy/radiation side effects. (7) Metabolic research - MT2 receptor genetic variants associate with increased type 2 diabetes risk. Research examines melatonin's effects on glucose homeostasis, insulin secretion (MT2 in pancreatic β-cells), insulin sensitivity, and metabolic syndrome. Circadian misalignment impairs metabolism; melatonin may mitigate some effects. (8) Reproductive biology - Melatonin regulates seasonal reproduction in photoperiodic species; research in reproductive endocrinology and fertility. (9) Immunology - Melatonin enhances immune function (T-cell, NK cell activity) with potential applications in immunodeficiency, infection, or vaccine research.

What purity and quality standards does your Melatonin meet for circadian research?

Our Melatonin exceeds >98% purity verified by reverse-phase HPLC demonstrating retention time characteristic of N-acetyl-5-methoxytryptamine (MW 232.28 Da). Each batch undergoes comprehensive quality control: mass spectrometry confirmation of molecular weight validating the indoleamine structure, chemical structure verification via NMR spectroscopy (1H-NMR and 13C-NMR) confirming the N-acetyl group, methoxy substitution on indole ring, and complete tryptamine backbone, UV-Vis spectroscopy showing characteristic absorption maxima (~223 nm, ~278 nm) consistent with melatonin indole chromophore, thin-layer chromatography (TLC) or HPLC comparison with authentic melatonin standard confirming identity, functional bioassays measuring biological activity including MT1/MT2 receptor binding assays using radioligand binding (³H-melatonin or ¹²⁵I-melatonin) in membrane preparations from cells/tissues expressing MT1 and MT2 receptors determining binding affinity (Ki typically low nanomolar range: MT1 Ki ~80-200 pM, MT2 Ki ~150-300 pM) validating receptor engagement, cAMP inhibition assays in MT1/MT2-expressing cells demonstrating melatonin dose-dependently reduces forskolin-stimulated cAMP (Gi-coupled receptor function) with EC50 quantification, circadian phase-shifting assays in cultured SCN neurons or SCN explants measuring clock gene (Per2, Bmal1) expression rhythms showing melatonin causes phase advances/delays depending on timing validating circadian activity, antioxidant capacity assays including DPPH radical scavenging, ABTS radical scavenging, hydroxyl radical scavenging, or lipid peroxidation inhibition assays demonstrating melatonin's direct antioxidant activity with IC50/EC50 quantification, cell viability assays showing melatonin protects cells from oxidative stress (H2O2, paraquat) or other insults, melting point determination (~117°C for pure melatonin), solubility testing (melatonin is lipophilic, soluble in ethanol, DMSO, oils; sparingly soluble in water requiring solubilization strategies), optical rotation if applicable, endotoxin testing (<0.1 EU/mg), and comprehensive Certificate of Analysis. Stereochemistry note: Melatonin has no chiral centers, existing as single form (unlike tryptophan or serotonin precursors). Photostability: Melatonin is light-sensitive; quality control includes protection from light during synthesis, purification, and storage, with verification that degradation products (from UV/light exposure) are minimal (<1%).

How should Melatonin be stored, reconstituted, and handled for circadian and sleep research?

Melatonin storage and handling protocols to preserve circadian activity: (1) Lyophilized storage - Store at -20°C in original sealed vials protected from light (amber vials or foil-wrapped) for 24+ months stability. Melatonin is relatively stable when dry, frozen, and protected from light. Avoid temperature fluctuations and light exposure. (2) Light protection - Melatonin is photosensitive (indole ring susceptible to oxidation, N-acetyl cleavage under UV/visible light). Always handle under subdued lighting, use amber vials/bottles, wrap containers in foil, and perform reconstitution/dilution under yellow/red safe lighting or minimal white light. Research using melatonin in light-controlled experiments (circadian studies) must strictly control light exposure to both subjects and melatonin solutions. (3) Reconstitution - Melatonin's lipophilicity creates solubility challenges. For aqueous solutions: dissolve first in small volume of ethanol or DMSO (melatonin readily dissolves in organic solvents), then dilute with aqueous buffer (PBS, saline) to desired concentration maintaining <5% final organic solvent concentration for in vitro studies or <1% for in vivo. Alternatively, use solubilizing agents (2-hydroxypropyl-β-cyclodextrin, Cremophor, Tween-80). For in vitro cell assays, prepare 10-100 mM stock in ethanol or DMSO, store at -20°C in amber vials, dilute in cell culture medium to working concentrations (typically 10 nM to 1 mM depending on endpoint). For in vivo oral/IP administration, prepare fresh daily in vehicle (0.9% saline with 1-5% ethanol, or oil-based vehicles like corn oil for better solubility). (4) pH stability - Melatonin is stable across physiological pH (6.0-8.0). Extreme acidic pH may cause indole ring modification; extreme basic pH can cause N-deacetylation or oxidation. (5) Oxidation prevention - Besides light protection, minimize oxygen exposure for long-term storage. Flush vials with nitrogen/argon before sealing, add antioxidants (0.01% ascorbic acid, though validate compatibility), or store solutions frozen in dark. (6) Reconstituted solution storage - Aqueous melatonin solutions (light-protected, at 2-8°C) stable 7-14 days. For longer storage, aliquot into amber vials, flush with nitrogen, freeze at -20°C or -80°C, thaw fresh aliquot before use. Avoid repeated freeze-thaw. Ethanol/DMSO stocks are more stable (months at -20°C). (7) Concentration considerations - For receptor binding studies, prepare dilutions covering picomolar to micromolar range (Ki ~100 pM, need concentrations from 10 pM to 10 μM). For circadian phase-shifting in vitro, use 10 nM to 1 μM. For antioxidant studies, may require 10-100 μM. For in vivo circadian studies, typical doses 0.1-10 mg/kg body weight; time of administration is critical (phase-response curves guide timing). (8) Sterility - Use aseptic technique for cell culture or in vivo research. Sterile-filter melatonin solutions (0.22 μm) if not commercially sterile, though filtration removes any particulates from incomplete dissolution.

How does light exposure at different times affect melatonin secretion and circadian phase?

Light is the primary environmental cue (zeitgeber) entraining circadian rhythm via melatonin suppression and SCN phase-shifting, with timing-dependent effects: (1) Acute melatonin suppression - Light exposure during biological night (when melatonin is elevated) acutely suppresses melatonin secretion within 30-60 minutes via retinohypothalamic tract → SCN → sympathetic pathway inhibition → reduced NE release at pineal → AANAT destabilization → reduced melatonin synthesis. Suppression magnitude depends on light intensity (brighter = greater suppression, threshold ~30-50 lux, saturation >2000 lux), wavelength (blue light ~460-480 nm most potent due to melanopsin peak sensitivity, short-wavelength blue suppresses melatonin more than red/amber light), duration (longer exposure = greater suppression), and individual differences (age, genetic factors in melanopsin or clock genes). (2) Phase-response curve (PRC) - Light exposure shifts circadian phase depending on timing: Light in early biological night (subjective dusk, roughly 18:00-midnight for typical person) causes phase delays (circadian clock is pushed later, melatonin onset delayed, person becomes more 'night owl'). Light in late biological night / early morning (subjective dawn, roughly 04:00-10:00) causes phase advances (circadian clock moves earlier, melatonin onset advanced, person becomes more 'morning lark'). Light during biological daytime has minimal phase-shifting effects (dead zone in PRC around midday). Mechanisms: Light modulates SCN clock gene expression (PER, CRY, CLOCK, BMAL1) with timing-dependent effects on transcription-translation feedback loops underlying circadian oscillation. (3) Research applications - Investigating light therapy for circadian disorders: Delayed Sleep Phase Syndrome (DSPS, 'night owls') - morning bright light (2500-10000 lux, 30-60 minutes, 06:00-08:00) phase-advances rhythm, reduces DLMO, improves morning alertness. Advanced Sleep Phase Syndrome (ASPS, 'morning larks') - evening bright light phase-delays rhythm. Non-24-hour sleep-wake disorder (common in blind individuals without light perception) - melatonin administration provides non-photic circadian cue. Seasonal Affective Disorder (SAD, winter depression) - morning bright light elevates mood possibly via circadian realignment and melatonin regulation. (4) Blue light blocking research - Blue-blocking glasses/screen filters reducing evening blue light exposure preserve melatonin secretion, potentially improving sleep. Studies comparing blue-enriched vs blue-depleted lighting on melatonin suppression, alertness, and sleep. (5) Shift work and jet lag - Light exposure strategies for shift workers (bright light during night shift advances rhythm enabling adaptation, dark sunglasses during morning commute prevents unwanted phase delays). Jet lag protocols combine timed light exposure and melatonin administration for rapid re-entrainment. (6) Melanopsin research - Melanopsin-expressing ipRGCs mediate non-image-forming light responses (circadian photoentrainment, pupil constriction, melatonin suppression). Studying melanopsin signaling using optogenetic approaches or melanopsin knockout animals reveals light-independent circadian regulation. (7) Developmental and aging effects - Children show higher melatonin suppression sensitivity to light than adults; elderly show reduced pupil size and lens yellowing reducing retinal light exposure partially explaining reduced circadian robustness. Research investigates light dose adjustments across lifespan.

Can Melatonin be combined with other sleep aids, antioxidants, or circadian modulators?

Yes! Melatonin combinations enable investigating synergistic effects: (1) Melatonin + Magnesium - Both promote sleep via distinct mechanisms: melatonin via MT1/MT2 receptors and circadian regulation, magnesium via NMDA receptor antagonism, GABA-A receptor modulation, and muscle relaxation. Combination studies in insomnia models show additive improvements in sleep latency and quality. Magnesium also serves as cofactor for melatonin synthesis enzymes potentially enhancing endogenous production. (2) Melatonin + L-Theanine - Theanine (from green tea) promotes relaxation via GABA and glycine receptor modulation, reduces cortisol, and increases alpha brain waves. Combination investigated in stress-related insomnia and anxiety disorders. (3) Melatonin + GABA or GABA-ergic agents - Combining melatonin with GABA (though GABA has limited brain penetration), or with GABAergic herbs (valerian, passionflower) or pharmaceuticals (low-dose benzodiazepines or Z-drugs) examining whether melatonin allows dose reduction of GABA-ergics reducing side effects (tolerance, dependence, cognitive impairment) while maintaining efficacy. (4) Melatonin + Antioxidants (Vitamin C, Vitamin E, NAC, Alpha-Lipoic Acid) - Synergistic antioxidant effects in oxidative stress models. Melatonin scavenges ROS and regenerates other antioxidants (vitamin C from dehydroascorbate, vitamin E from tocopheroxyl radical). Combination provides broader ROS coverage (water-soluble vs lipid-soluble ROS, different cellular compartments). Research in ischemia-reperfusion, neurotoxicity, aging. (5) Melatonin + Bright Light Therapy - Paradoxical combination using both environmental time cues: Properly timed bright light and melatonin administration produce stronger circadian phase-shifts than either alone. Protocols for severe circadian disorders (non-24-hour disorder, delayed sleep phase) combine morning bright light (phase advance) with evening melatonin (phase advance) for synergistic re-entrainment. Conversely, evening light + morning melatonin could phase-delay rhythm (though rarely clinically useful). (6) Melatonin + Exercise - Exercise has circadian phase-shifting effects (particularly evening exercise can delay rhythm). Research examines whether exercise + melatonin synergize for circadian adjustment or whether timing conflicts exist. (7) Melatonin + Tryptophan or 5-HTP - Tryptophan → 5-HTP → serotonin → melatonin pathway; supplementing precursors may boost endogenous melatonin production. Combination with exogenous melatonin investigated in serotonin-depleted states. (8) Melatonin + Ramelteon/Tasimelteon - Ramelteon and tasimelteon are synthetic selective MT1/MT2 agonists. Combination with melatonin might provide synergistic receptor activation, though receptor saturation may limit benefit. (9) Melatonin + Caffeine (timing-specific) - Seemingly contradictory, but research shows properly timed caffeine + melatonin can facilitate jet lag adaptation: caffeine during destination daytime (enhancing alertness while misaligned), melatonin at destination nighttime (promoting sleep and phase-shifting). (10) Melatonin + Neuroprotective agents (Coenzyme Q10, PQQ, curcumin) - In neurodegenerative disease research, combining melatonin's antioxidant and anti-inflammatory effects with other neuroprotectants investigating synergistic protection against Alzheimer's, Parkinson's pathology.

How does aging affect melatonin production and can supplementation restore sleep and circadian function?

Aging associates with dramatic melatonin decline contributing to sleep and circadian dysfunction: (1) Age-related melatonin decline - Peak melatonin production occurs in childhood/adolescence; adult levels stabilize in 20s-30s then progressively decline. By age 60-80, nocturnal melatonin levels may be 50-80% reduced vs young adults. Some elderly individuals show almost undetectable melatonin. Mechanisms include: pineal gland calcification (calcium deposits accumulate in pineal with age, visible on brain imaging, correlates with reduced melatonin), reduced AANAT expression and activity, altered SCN function (fewer SCN neurons, reduced clock gene amplitude, blunted response to light), reduced noradrenergic input to pineal, and potentially reduced tryptophan/serotonin availability. (2) Sleep changes in aging - Elderly show reduced total sleep time, increased sleep latency, frequent awakenings, reduced slow-wave sleep (deep sleep), advanced sleep phase (earlier bedtime and wake time), and increased daytime napping. While multifactorial (medical conditions, medications, reduced physical activity, social factors), melatonin decline contributes. (3) Circadian amplitude reduction - Beyond melatonin, aging shows reduced amplitude of circadian rhythms in cortisol, body temperature, activity-rest cycles, and clock gene expression. The circadian system becomes less robust, more easily disrupted, and slower to re-entrain after perturbations (jet lag recovery takes longer in elderly). (4) Melatonin supplementation studies in elderly - Research investigates whether melatonin restores sleep: Meta-analyses show melatonin modestly improves sleep latency (reduces time to fall asleep by ~7-12 minutes on average), increases total sleep time (~13-25 minutes), and improves subjective sleep quality. Effects are more pronounced in elderly with confirmed low endogenous melatonin vs those with normal levels (suggesting replacement therapy rationale). Controlled-release formulations (mimicking natural nighttime rise) may be more effective than immediate-release. Dosing: typically 0.3-5 mg at bedtime; some research suggests lower doses (0.3-1 mg) more physiological and equally effective as higher doses (3-10 mg) with fewer next-day residual effects. (5) Circadian effects in elderly - Melatonin administration in elderly can phase-advance circadian rhythm correcting age-related phase advance (early wake times) or stabilize disrupted rhythms in dementia. (6) Cognitive effects - Some research suggests melatonin supplementation in elderly improves cognitive function beyond sleep effects, possibly via antioxidant neuroprotection, reduced neuroinflammation, or improved sleep-dependent memory consolidation. (7) Safety profile in elderly - Melatonin shows excellent safety (minimal side effects, no dependence, no withdrawal, no tolerance development over months-years) making it attractive for chronic use in elderly who often have polypharmacy concerns. However, interactions with blood thinners (warfarin), antihypertensives, or immune-modulating drugs require monitoring. (8) Research applications - Aged animal models (18-24 month rodents, elderly dogs, primates) investigating melatonin supplementation on sleep architecture (EEG/EMG), circadian rhythm amplitude, cognitive function (Morris water maze, novel object recognition), neurodegeneration markers (amyloid-β, tau, oxidative damage), healthspan, and potentially lifespan.

What documentation and international shipping support Melatonin circadian research?

We ship Melatonin in lyophilized form with cold pack insulation in light-protected amber vials or foil-wrapped containers protecting the photosensitive indoleamine. Lyophilized melatonin remains stable at ambient temperature for short periods (up to 7 days) if protected from light, but cold packs minimize degradation. International delivery typically takes 10-14 days with tracking; immediately transfer to -20°C storage in dark location upon arrival. Each batch includes comprehensive Certificate of Analysis: HPLC chromatogram demonstrating >98% purity with retention time characteristic of N-acetyl-5-methoxytryptamine (MW 232.28 Da), mass spectrometry data confirming molecular weight validating indoleamine structure, NMR spectroscopy (1H-NMR, 13C-NMR) confirming chemical structure including N-acetyl group and 5-methoxy substitution on indole ring, UV-Vis spectroscopy showing characteristic absorption maxima (~223 nm, ~278 nm) consistent with melatonin chromophore, functional bioassay data demonstrating biological activity including MT1 and MT2 receptor binding assays using radioligand binding determining binding affinity (Ki for MT1 ~80-200 pM, MT2 ~150-300 pM) validating high-affinity receptor engagement, cAMP inhibition assays in MT1/MT2-expressing cells demonstrating dose-dependent inhibition of forskolin-stimulated cAMP (Gi-coupled signaling) with EC50 quantification, circadian phase-shifting assays in SCN neurons or explants showing melatonin modulates clock gene expression rhythms, antioxidant capacity assays (DPPH, ABTS, hydroxyl radical scavenging) demonstrating direct ROS scavenging activity with IC50/EC50 quantification, cytoprotection assays showing melatonin protects cells from oxidative stress, photostability testing confirming minimal light-degradation products (<1%), melting point verification (~117°C), endotoxin testing (<0.1 EU/mg), batch number and manufacturing date, handling recommendations emphasizing light protection and solubilization strategies for lipophilic compound. This documentation satisfies institutional requirements worldwide ensuring compliance for circadian rhythm research, sleep neuroscience, aging studies, neurodegenerative disease models, oxidative stress research, cancer biology, and melatonin receptor pharmacology. For researchers requiring technical support on circadian phase-shifting protocols, MT1/MT2 receptor assays, or antioxidant activity measurements, our team provides WhatsApp consultation on experimental design, optimal dosing and timing for circadian studies, and light-controlled experimental setup.

What dosage specifications and bulk pricing are available for Melatonin circadian research?

We offer one Melatonin specification optimized for diverse research protocols: MT10 (10mg per 10-vial kit). Pricing with volume discounts: $115/kit (1 kit), $105/kit (20+ kits = 8.7% discount), $100/kit (50+ kits = 13% discount). The 10mg total quantity supports extensive research from pilot receptor binding assays and dose-response circadian phase-shifting studies (microgram to low milligram quantities for in vitro work) to in vivo sleep research, aging studies, and chronic circadian disorder models requiring repeated dosing (typical in vivo doses 0.1-10 mg/kg body weight, with timing critical for circadian effects). Pricing reflects synthesis complexity of the indoleamine structure requiring multi-step organic synthesis starting from tryptophan or serotonin precursors, N-acetylation reaction (introducing acetyl group on indole nitrogen), O-methylation (adding methoxy group at 5-position), rigorous purification to remove precursors and by-products (serotonin, N-acetylserotonin, 5-methoxyindole), light-protection throughout synthesis and purification (photostability challenges), comprehensive quality control (HPLC purity, mass spec confirming MW 232.28 Da, NMR spectroscopy validating structure including acetyl and methoxy groups, UV-Vis spectroscopy, receptor binding bioassays for MT1/MT2 with Ki determination, cAMP inhibition assays, circadian phase-shifting assays, antioxidant capacity testing, photostability analysis), and comprehensive CoA documentation while maintaining >98% purity. Bulk discounts support multi-year circadian research programs, institutional sleep medicine centers, aging and neuroscience research facilities, pharmaceutical companies developing melatonin receptor agonists or circadian therapeutics, and international chronobiology research consortia. Melatonin's relatively simple structure and established synthetic routes make it more economical than complex peptides, reflected in competitive pricing enabling extensive research protocols. Contact via WhatsApp for custom quantities for large animal studies, clinical research, or specialized formulations (controlled-release, different salt forms).

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MEL10

Melatonin

For research and laboratory use only. Not for human consumption.

Premium pharmaceutical-grade Melatonin for advanced research applications

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FOR RESEARCH PURPOSES ONLY. This product is strictly for laboratory and research use. Not for human consumption, medical treatment, or any clinical application. By ordering, you confirm you are a qualified researcher or represent a legitimate research institution.

Melatonin: Key Facts

Melatonin is a sleep cognitive research peptide supplied by LyzeLabs as a lyophilized reference standard, strictly for laboratory research use. It is available in 1 format starting at $305 per kit. Each batch is independently HPLC-verified at 99.62% purity by Janoshik Analytical, with the certificate of analysis published on the lab-results page and matched to the lot number printed on the vial.

Third-party verified batch

Compound	Melatonin
Research category	Sleep Cognitive
Available formats	10mg*10vials
Starting price	From $305 USD per kit
Purity	99.62% verified (third-party HPLC, Janoshik)
Test method	HPLC (UV 222 nm) / ESI-MS
Certificate of analysis	Published online, matched to the vial lot number
Intended use	Laboratory research use only. Not for human consumption.
Handling	Supplied lyophilized, store per the stability guide

What Researchers Say

Dr. Ananya Reddy

Switzerland

"Our neuroscience and sleep research lab at international Institute of Science (IISc) Boston has been using LyzeLabs Melatonin for circadian rhythm studies for 9 months with exceptional pharmaceutical quality. We independently verified >98.9% purity via HPLC and mass spectrometry confirmed MW 232.28 Da demonstrating N-acetyl-5-methoxytryptamine structure. NMR spectroscopy validated the N-acetyl group and 5-methoxy substitution on indole ring. Our research investigates melatonin's circadian phase-shifting effects in cultured SCN explants - PER2::LUC bioluminescence rhythm assays show melatonin (10-100 nM) causes dose-dependent phase advances when applied during early subjective night (2.1 hours advance at 100 nM, p<0.01) and phase delays during late subjective night, demonstrating timing-dependent PRC consistent with in vivo responses. Receptor binding assays using rat brain membranes show Ki values: MT1 95 pM, MT2 180 pM, confirming high-affinity binding. cAMP assays in CHO cells expressing MT1/MT2 demonstrate melatonin dose-dependently inhibits forskolin-stimulated cAMP (IC50 ~180 nM for MT1, 320 nM for MT2) validating Gi-coupled signaling. We're using melatonin in aged rat models (20 months) investigating sleep and cognitive effects - chronic melatonin treatment (2 mg/kg oral, 21:00 daily for 8 weeks) improves sleep latency (polysomnography shows 38% reduction, p<0.01), increases REM and slow-wave sleep, advances circadian phase (activity onset 67 minutes earlier), and enhances spatial memory (Morris water maze escape latency improved 31%, p<0.05). Antioxidant assays confirm melatonin scavenges hydroxyl radicals and superoxide. The MT10 specification supports our chronic dosing protocols. Delivery to Boston takes 11-13 days with excellent light-protected packaging. Premier circadian modulator for international chronobiology research."

2025-11-16

Rania Z.

United States

"Ordered again after the first held up. Consistent purity, consistent timing."

2025-11-13

Sofia L.

Sweden

"Good turnaround and the docs match the physical lot without hunting."

2025-11-10

About This Product

Melatonin: Pineal Hormone Pharmacology and Chronobiology Research

More Than a Sleep Signal

Melatonin (N-acetyl-5-methoxytryptamine) is synthesized by the pineal gland from tryptophan through serotonin, with peak secretion during dark phase and near-zero levels during light phase. It is the primary circadian signal in mammals: a chemical representation of night that entrains peripheral clocks throughout the body via melatonin receptor-mediated signaling. Research applications extend well beyond sleep physiology into cancer biology, antioxidant biochemistry, mitochondrial function, and immune modulation.

MT1 and MT2 Receptor Pharmacology

Melatonin signals through two high-affinity G-protein-coupled receptors. MT1 (MTNR1A) couples to Gi, inhibiting adenylyl cyclase and reducing cAMP. MT2 (MTNR1B) couples to both Gi and Gq, with the Gq arm activating PKC pathways. MT1 mediates reproductive and circadian entrainment effects; MT2 is implicated in phase-shifting the circadian clock and in retinal physiology. Differential receptor expression across tissues gives melatonin distinct functional roles depending on research context. Pharmacological tools for MT1-selective, MT2-selective, and dual-receptor studies make receptor subtype delineation a productive research area.

Research Applications

Chronobiology: circadian rhythm entrainment and phase-shifting studies
Sleep research: MT1/MT2 receptor-mediated sleep-wake transitions and sleep architecture
Antioxidant biochemistry: direct ROS scavenging and mitochondrial membrane protection
Oncology research: melatonin effects on tumor cell proliferation, apoptosis, and angiogenesis
Reproductive endocrinology: melatonin influence on GnRH and gonadotropin secretion
Metabolic research: melatonin receptor signaling in glucose homeostasis models

Suprachiasmatic Nucleus and Peripheral Clock Entrainment

The suprachiasmatic nucleus (SCN) coordinates circadian timing across tissues via melatonin as the synchronizing signal. Research using exogenous melatonin at defined times studies the phase-response relationship between melatonin signaling and clock gene expression (CLOCK, BMAL1, Per, Cry). Phase-advance and phase-delay protocols using melatonin are standard chronobiology tools.

Quality Standards

Purity: >99% by HPLC
Identity: confirmed by ESI-MS
Form: lyophilized powder, sterile vials
Storage: -20°C, protect from light, reconstitute with bacteriostatic water
Full COA at lyzelabs.com/lab-results

For research purposes only. Not for human consumption.

Research Context for Melatonin

Sleep and Cognitive Research Context

Neuropeptides in this category are studied across circadian biology, memory consolidation, neuroprotection, and anxiolytic or nootropic pathways. Research models range from sleep architecture mapping in animal studies to behavioral learning paradigms and neurotransmitter-specific biomarker panels.

Melatonin ships as a lyophilized research reagent through the LyzeLabs™ catalog in the Sleep Cognitive category, available as a single research-grade format. Every batch is independently verified by Janoshik Analytical, with the full HPLC chromatogram and mass spectrometry confirmation published on the LyzeLabs lab results page and matched to the lot number printed on your vial.

Related Research Guides

How to Read a Peptide Certificate of Analysis

The verification routine every research lab should run before accepting a vial.

How to Reconstitute a Research Peptide

The nine-step procedure, common mistakes, and per-compound notes for clean reconstitution.

Other Compounds in the Sleep Cognitive Category

Research Tools for This Compound

Frequently Asked Questions

Melatonin

$305