What is Melatonin?

Melatonin is a hormone produced by the pineal gland from tryptophan → serotonin → melatonin in a light-dependent pathway. It is fundamentally a circadian rhythm regulator — it signals the body that it is nighttime, coordinating the sleep-wake cycle and multiple downstream physiological processes.

A critical misunderstanding: melatonin is not a sedative. It does not knock you out or create drowsiness in the way that sedatives, antihistamines, or benzodiazepines do. Instead, it tells the brain "it is dark, prepare for sleep" — initiating the physiological cascade that leads to sleep: core body temperature drop, reduced metabolic rate, and shifting of neural activity patterns. If you are already awake in a bright room, melatonin has minimal immediate effect — its action is circadian, not directly hypnotic.

The India Dose Problem

The natural nocturnal melatonin peak in humans is approximately 0.1–0.3 nanomoles/L (roughly equivalent to 0.3–0.5mg oral supplementation). Most supplements sold in India and internationally come in 5mg or 10mg doses — 10–30 times the physiological level.

This matters because:

• Supraphysiological doses do not produce better sleep outcomes than low doses in RCTs — the dose-response relationship is not linear
• High doses cause morning grogginess, vivid dreams, and next-day fatigue in many users
• Chronically high melatonin may downregulate melatonin receptors and potentially suppress endogenous melatonin synthesis
• The hormone signalling system is designed for picomolar-nanomolar concentrations — flooding receptors at supraphysiological concentrations disrupts the signal rather than amplifying it

Sleep Onset vs Sleep Quality — What Melatonin Actually Does

The clinical evidence is specific about what melatonin does and doesn't do:

• Sleep latency (time to fall asleep): Reduced by 7–12 minutes in most meta-analyses. This is modest but meaningful for circadian phase-advanced individuals.
• Total sleep time: Minimal effect — melatonin does not significantly extend total sleep duration
• Sleep architecture (deep sleep, REM): Limited evidence of meaningful improvement
• Circadian phase-shifting: Strong effect — this is melatonin's true primary application

For improving overall sleep quality (deeper sleep, better architecture, more refreshing sleep), magnesium glycinate is more effective than melatonin. The combination can be useful: melatonin for falling asleep (circadian signal), magnesium for quality once asleep.

The Antioxidant Angle — Beyond Sleep

Melatonin's longevity significance extends beyond circadian regulation. It is one of the most potent mitochondrial antioxidants known:

• Melatonin is highly lipid-soluble and crosses all cell membranes — including the blood-brain barrier and mitochondrial membranes
• It concentrates specifically in mitochondria, where it directly scavenges reactive oxygen species (ROS) generated during electron transport
• In some experimental contexts, melatonin is 10–100× more powerful than Vitamin E as a mitochondrial antioxidant
• Melatonin upregulates endogenous antioxidant enzymes: SOD (superoxide dismutase), GPx (glutathione peroxidase), and catalase
• Endogenous melatonin production declines significantly with age — falling roughly 50% per decade from age 40

This decline in mitochondrial antioxidant protection with age parallels — and may partially drive — the increase in mitochondrial dysfunction, DNA damage, and age-related diseases. Low-dose melatonin supplementation (0.3–0.5mg) is increasingly argued as a longevity intervention for this reason, separate from sleep.

Melatonin Dose Effect Table

Jet Lag Protocol

Melatonin is most strongly evidence-backed for jet lag — this is a circadian phase-shifting application, which is melatonin's native function:

• Eastward travel (crosses 3+ time zones): Take 0.5mg at your destination's target bedtime (9–10pm local) for 3–5 nights. This advances your circadian clock to the new timezone.
• Westward travel: Less effective (delaying circadian phase is harder); take in the early evening of destination time if needed.
• Short trips (under 3 days): May not be worth adjusting — your body will readjust on return.

Seasonal & India-Specific Context

India's geography (close to the equator) means relatively consistent day lengths year-round compared to higher latitudes. However, urban professionals in India face several factors that disrupt melatonin production:

• Artificial light at night: Blue-spectrum light from phones, LED screens, and indoor lighting suppresses melatonin secretion even at low intensities — delaying sleep onset
• Late night social culture: Evening socialising and late dinner times push circadian rhythms later
• Air conditioning and sealed environments: Reduce natural light-dark contrast

Blue-light blocking glasses worn from 9pm onward may do more to support natural melatonin production than supplementation, by preventing the suppression of endogenous output.

Drug Interactions & Contraindications

Drug interactions:

• Blood thinners (warfarin): Melatonin may slightly inhibit platelet aggregation — monitor INR if on warfarin
• Immunosuppressants: Melatonin has immunomodulatory effects — may interact with cyclosporine and similar drugs
• Benzodiazepines and sedatives: Additive sedation — use with caution
• Diabetes medications: May affect glucose metabolism — monitor glucose if diabetic

When NOT to use:

• Clinical depression — some evidence that high-dose melatonin may reduce serotonergic activity and worsen mood in susceptible individuals
• Active autoimmune conditions — melatonin's immunostimulatory effects may exacerbate
• Pregnancy — insufficient safety data; avoid unless under physician guidance

Frequently Asked Questions

Related Terms