Sleep supplements: what melatonin is actually for, and why magnesium is not a sedative

The sleep aisle sells a promise that is unusually hard to test, because everyone eventually sleeps and nobody remembers falling asleep accurately. That makes it fertile ground for products with thin evidence.

Melatonin, precisely

Melatonin is a hormone that signals darkness. It is a timing cue, not a sedative - which is why it works well for problems of timing and much less well for lying awake with a busy mind.

• Best evidence: jet lag, shift work, and delayed sleep phase - where your body clock and your schedule disagree.
• Timing matters more than dose: typically taken some hours before the target bedtime for phase shifting.
• Lower doses often work as well as higher ones. Commonly sold strengths are considerably above what the research typically uses.
• It is not habit forming in the way sedatives are, and it is not a treatment for chronic insomnia.
• Availability in India varies by formulation and presentation - check whether you are buying a supplement or a drug preparation, and ask a pharmacist. It is not appropriate for children without medical advice.

If you need something every night to sleep, the thing to investigate is why - not which product. Chronic insomnia has effective treatment, and the first-line option internationally is cognitive behavioural therapy for insomnia rather than any tablet.

Magnesium and the rest

When it is medical

Some sleep problems are not going to respond to anything you can buy.

• Loud snoring with pauses in breathing, or waking unrefreshed despite enough hours - possible sleep apnoea, which is common, under-diagnosed and treatable.
• Restless, crawling sensations in the legs at night - restless legs syndrome, often linked to low iron stores.
• Early morning waking with low mood - depression presents this way frequently.
• Thyroid disease, uncontrolled pain, reflux, and several medicines including some taken for blood pressure and asthma.
• Sleep problems lasting more than a month, or affecting your ability to work or drive safely.

The unglamorous things that work better

• A consistent wake time, seven days a week. It anchors the body clock more powerfully than bedtime does.
• Morning daylight, which is the strongest available cue and free.
• Caffeine cut off eight hours before bed - its half-life is long enough that the 4 pm coffee is still present at midnight.
• Alcohol out of the evening. It helps you fall asleep and reliably damages the second half of the night.
• A cool, dark room - genuinely difficult in Indian summers, and worth solving with a fan, curtains or cooling rather than with a tablet.
• Getting out of bed if you have been awake for twenty minutes, so the bed does not become the place where you lie awake.
• Screens are less of a villain than the content on them. It is usually the stimulation, not the blue light, that keeps you up.

Supplements can smooth a specific problem - a time-zone change, a rotating shift, a run of stressful weeks. As a nightly solution to a sleep problem nobody has diagnosed, they mostly delay the thing that would have fixed it.