MELATONIN

Melatonin is a naturally occurring hormone best known for regulating the sleep–wake cycle.
Melatonin is widely used in supplements designed to support sleep quality, circadian rhythm balance, and jet lag management.
Melatonin is also recognized for its antioxidant properties and its importance in wellness-focused formulations.

CAS number: 73-31-4
Molecular formula: C13H16N2O2
Molecular mass: 232.28 g/mol

Synonyms: N-Acetyl-5-methoxytryptamine, 5-Methoxy-N-acetyltryptamine, Melatonina, Melatonin hormone, Pineal hormone, Sleep hormone, Circadian hormone, N-Acetyl methoxytryptamine, Methoxytryptamine derivative, Biogenic indoleamine

Melatonin is a naturally occurring indoleamine hormone that helps regulate the sleep–wake cycle and circadian rhythm in humans and other living organisms.
Melatonin is mainly produced by the pineal gland in response to darkness and is widely used in dietary supplements, nutraceutical formulations, and sleep-support products. 
Melatonin is also valued for its antioxidant activity and its role in supporting biological rhythm balance.

Melatonin is a biologically active indoleamine compound synthesized primarily in the pineal gland from the amino acid tryptophan through serotonin intermediates.
Melatonin plays a central role in the regulation of circadian rhythms by signaling the onset of darkness to the body, thereby coordinating physiological processes such as sleep timing, hormone secretion, body temperature, and metabolic activity.

Melatonin's secretion follows a daily cycle, with levels rising in the evening, peaking during the night, and decreasing toward morning.
Beyond its chronobiological function, melatonin exhibits strong antioxidant and free radical scavenging properties, contributing to cellular protection against oxidative stress and supporting overall physiological balance.

Melatonin is also involved in immune modulation, neuroprotection, and regulation of inflammatory responses, which has expanded its relevance in nutraceutical, pharmaceutical, and functional food applications.
Industrially, melatonin is produced via controlled chemical synthesis to ensure high purity, consistency, and suitability for use in dietary supplements, research formulations, and health-related products.
Due to Melatonin's sensitivity to light, heat, and moisture, proper formulation and packaging are critical to maintain its stability and efficacy throughout its shelf life.

Uses of Melatonin:
Melatonin is widely used in dietary supplements formulated to support sleep regulation by helping reduce sleep onset time and improving overall sleep quality.
Melatonin is commonly included in products designed for individuals experiencing insomnia, irregular sleep patterns, or difficulty adapting to shift work schedules.

Melatonin is also used for managing jet lag by helping the body adjust more quickly to new time zones and restoring the natural circadian rhythm.
In clinical and research settings, Melatonin is applied in chronobiology studies to investigate biological rhythms and hormonal regulation mechanisms.
In nutraceutical and functional health products, melatonin is valued for its antioxidant properties, contributing to cellular protection against oxidative stress.

Melatonin is sometimes incorporated into formulations targeting immune system support, stress management, and general wellness.
Additionally, melatonin is explored in pharmaceutical applications for its potential neuroprotective, anti-inflammatory, and endocrine-regulating effects, making it relevant in advanced therapeutic research and specialized medical formulations.

Benefits of Melatonin:

Sleep regulation:
Melatonin supports the natural sleep–wake cycle by signaling the body that it is time to rest, helping to improve sleep onset and overall sleep quality.

Circadian rhythm balance:
Melatonin helps synchronize the internal biological clock, making it especially useful for individuals with disrupted daily rhythms such as shift workers.

Jet lag reduction:
Melatonin assists in faster adaptation to new time zones by resetting the body’s internal timing system.

Antioxidant protection:
Melatonin acts as a strong free radical scavenger, helping protect cells from oxidative damage and supporting overall cellular health.

Immune system support:
Melatonin contributes to the modulation of immune responses and may help maintain immune balance.

Stress response support:
Melatonin plays a role in regulating neuroendocrine function, which can help the body manage physiological stress.

Neuroprotective effects:
Melatonin is associated with protecting neural tissues and supporting brain health through its antioxidant and regulatory functions.

Hormonal regulation:
Melatonin interacts with various hormonal systems, contributing to overall physiological balance and metabolic stability.

Mechanism of Action
Melatonin exerts its biological effects primarily through binding to specific G-protein coupled receptors known as MT1 (Melatonin receptor 1) and MT2 (Melatonin receptor 2), which are widely distributed in the brain—especially in the Suprachiasmatic Nucleus (SCN)—as well as in peripheral tissues.

Circadian regulation:
Melatonin is secreted in response to darkness and binds to MT1 and MT2 receptors in the SCN, the body’s central biological clock.
This interaction reduces neuronal firing and shifts circadian phase timing, effectively signaling the body to transition into a sleep state.

Neurotransmission modulation:
Melatonin influences neurotransmitter systems, including inhibition of excitatory signals and modulation of gamma-aminobutyric acid (GABA) pathways.
This leads to a calming effect on the central nervous system and promotes sleep readiness.

Hormonal signaling:
Melatonin regulates endocrine activity by interacting with the hypothalamic–pituitary axis.
Melatonin influences the release of hormones such as cortisol and growth hormone, aligning them with the day–night cycle.

Antioxidant activity:
Melatonin acts both directly and indirectly as an antioxidant.
Melatonin scavenges reactive oxygen and nitrogen species and upregulates antioxidant enzymes such as superoxide dismutase and glutathione peroxidase, contributing to cellular protection.

Cellular signaling pathways:
Through receptor-mediated and receptor-independent mechanisms, melatonin modulates intracellular signaling cascades (such as cAMP and protein kinase pathways), affecting gene expression related to circadian rhythm, inflammation, and apoptosis.

Immunomodulation:
Melatonin influences immune cells by regulating cytokine production and enhancing immune response coordination, contributing to both anti-inflammatory and immune-supportive effects.

Stability and Reactivity of Melatonin:

Chemical stability:
Stable under recommended storage conditions.

Reactivity:
No hazardous reactions expected under normal use.

Conditions to avoid:
Excessive heat.
Moisture.
Direct light.

Incompatible materials:
Strong oxidizing agents.

Hazardous decomposition products:
Carbon oxides (CO, CO₂) may form.
Nitrogen oxides (NOₓ) may be released under fire conditions.

Handling and Storage of Melatonin:

Handling:
Avoid generating dust.
Avoid inhalation of dust.
Avoid contact with eyes.

Storage:
Store in a cool, dry, and well-ventilated place.

Storage conditions:
Keep container tightly closed.
Protect from light.
Protect from humidity.

Packaging materials:
Use well-sealed, light-resistant containers.

Shelf life:
Stable for extended periods when properly stored.

First Aid Measures of Melatonin:

Inhalation:
Move person to fresh air.

Skin contact:
Wash thoroughly with soap and water.

Eye contact:
Rinse cautiously with water for several minutes.

Ingestion:
Rinse mouth.
Seek medical advice if discomfort occurs.

Firefighting Measures of Melatonin:

Suitable extinguishing media:
Water spray.
Foam.
Dry chemical.
Carbon dioxide (CO₂).

Hazards:
Thermal decomposition may produce irritating or toxic fumes.

Protective equipment:
Firefighters should wear appropriate protective equipment.
Use self-contained breathing apparatus.

Accidental Release Measures of Melatonin:

Personal precautions:
Avoid dust formation.
Avoid inhalation of dust.

Spill response:
Sweep up carefully.
Place in a suitable container.

Environmental precautions:
Prevent unnecessary release into the environment.

Cleanup methods:
Use dry cleaning methods.
Dispose according to local regulations.

Exposure Controls / Personal Protection of Melatonin:

Respiratory protection:
Use a dust mask if airborne particles are generated.

Eye protection:
Use safety goggles.

Skin protection:
Wear protective gloves.

Hygiene measures:
Wash hands thoroughly after handling.

Identifiers of Melatonin:
Chemical name: Melatonin
IUPAC name: N-acetyl-5-methoxytryptamine
CAS number: 73-31-4
Molecular formula: C13H16N2O2
Molecular mass: 232.28 g/mol

Properties of Melatonin:
Appearance: White to off-white crystalline powder
Odor: Odorless or nearly odorless
Solubility: Slightly soluble in water, soluble in alcohol and some organic solvents
pH stability: More stable in controlled, dry conditions
Melting point: Approximately 116–118°C
Light sensitivity: Sensitive to prolonged light exposure