Melatonin Is Not a Sleeping Pill

There is a jar of melatonin gummies in a great many bedrooms now. Ten milligrams, one before bed, every night, for months. Sometimes two, because one stopped feeling like it did much.

It is the most misunderstood thing on the supplement shelf, and the misunderstanding is not the customer’s fault. It sits next to the sleep aids, it is packaged like a sleep aid, and almost nothing about how it is sold tells you what it actually is.

What melatonin actually is

Melatonin is a timing signal, not a sedative. Your pineal gland starts releasing it a couple of hours before your usual bedtime, once the light around you drops, and that release is how your body knows it is night. It does not switch you off. It tells your internal clock what time it is.

That distinction changes everything about how it should be used. A sleeping tablet works on dose — more sedation, more sleep. A timing signal works on timing. Taking a large dose at bedtime is a bit like shouting the time at someone who already knows it.

It is also worth knowing the scale. The amount your body produces in a night is measured in tens of micrograms. Doses used in the research on circadian timing are commonly 0.3 to 0.5 mg. The gummies on the shelf are usually 5 or 10 mg, and I have seen 20. That is ten to fifty times a physiological dose, taken nightly, on the assumption that more must be stronger.

What the guidelines actually say

The American Academy of Sleep Medicine reviewed the evidence and recommends that clinicians do not use melatonin to treat sleep onset or sleep maintenance insomnia in adults. It is a weak recommendation, which in guideline language means the certainty is limited rather than that the drug is proven useless — but it is a recommendation against, and it is the opposite of how the product is marketed.

Meanwhile the American College of Physicians recommends cognitive behavioural therapy for insomnia as the initial treatment for every adult with chronic insomnia, before any medication is considered. The first-line treatment for the thing most people are buying melatonin for is not a pill at all.

And you may not be getting what the label says

A study in the Journal of Clinical Sleep Medicine analysed 31 melatonin supplements. The actual melatonin content ranged from 83% below the label to 478% above it. More than seven in ten missed their stated dose by more than a 10% margin. Batch-to-batch variation within a single product reached 465%.

More concerning: 26% of the products contained serotonin, unlisted on the label. Serotonin is not a benign extra ingredient, particularly for anyone on an antidepressant.

So the honest position is that you are taking an unknown multiple of a dose that is already many times physiological, for an indication the guidelines advise against, from a category with poor quality control. That is three separate problems stacked on top of each other.

When melatonin genuinely helps

It is not useless. It is a good drug used for the wrong thing.

Where it has real support is circadian: jet lag, particularly flying east; delayed sleep phase, where someone naturally falls asleep at 3 am and cannot shift it; some shift work patterns; and non-24-hour rhythm disorders in blind people.

In those uses, the timing is the active ingredient. A small dose taken several hours before the target bedtime pulls the clock earlier. The same dose taken as you switch the light off does very little that is useful. If you are going to use it, use it as a clock adjustment for a specific reason and a defined period, rather than as a nightly habit of unclear purpose.

What actually works

A fixed wake time. The single most useful thing on this list, and the least popular. Your bedtime is an outcome; your wake time is the input. Hold it steady seven days a week, including after a bad night and including Sunday, and the rest of the rhythm organises itself around it.

Light, in the right direction. Bright light within an hour of waking, ideally outdoors. Dimmer light in the two hours before bed. This is the same lever melatonin pulls, operated by the mechanism that was designed for it.

Get out of bed when you are not sleeping. If you have been awake more than about twenty minutes, leave the bed, sit somewhere dim and dull, and go back when you feel sleepy. Lying awake teaches your brain that bed is where you lie awake. This is one of the components that makes CBT for insomnia work.

Spend less time in bed, not more. The instinct after a bad week is to go to bed at nine and hope. It reliably backfires. Compressing time in bed towards actual sleep time concentrates sleep and rebuilds the pressure to fall asleep quickly.

Watch the caffeine clock. Caffeine has a half-life of around five hours, so a four o’clock coffee still has half its dose working at nine. Many people who describe themselves as poor sleepers are simply drinking caffeine later than their body can clear it.

Alcohol is a sedative, not a sleep aid. It shortens the time to fall asleep and then fragments the second half of the night, which is why you wake at 3 am after a heavy evening.

Cool and dark, and be honest about the phone. The screen’s light matters less than what is on it. A dim screen showing something engrossing will keep you awake perfectly well.

When it is not insomnia

Some of the people who cannot sleep do not have a sleep habit problem. They have something with a name, and no amount of sleep hygiene will touch it.

• Obstructive sleep apnoea. Snoring, gasping or choking at night, waking unrefreshed, morning headaches, daytime sleepiness. This is common, seriously underdiagnosed, and needs a sleep study rather than a supplement
• Restless legs. An urge to move the legs in the evening that eases when you do. It is frequently driven by low iron stores, so ferritin is worth checking — and the target here is higher than the one your lab flags
• Depression and anxiety. Early morning waking is a classic feature of depression, and racing thoughts at night of anxiety. Both are treatable and neither is a discipline problem
• Thyroid disease, uncontrolled reflux, an enlarged prostate, and the menopause transition, all of which fragment sleep through entirely mechanical routes
• Your medicines. Steroids, some antidepressants, salbutamol inhalers, decongestants, thyroid replacement taken too late and diuretics taken too late are all common culprits. If your sleep changed when a prescription did, that is worth mentioning to whoever wrote it

What I will not tell you

That melatonin is dangerous or addictive. It is neither, in the ordinary sense. Short-term use is well tolerated, and it does not produce dependence the way older sleeping tablets do. The argument against nightly high-dose use is that it is unlikely to be doing what you think, not that it will harm you.

That you must get eight hours. Sleep need varies, and lying awake worrying about a number is itself a reliable way to sleep badly.

That you should stop a prescribed sleeping tablet because of anything in this article. Several of them, benzodiazepines and Z-drugs in particular, need a planned taper and cause real problems when stopped abruptly. That is a conversation with your doctor, not a decision to make after reading a blog.

The short version

• Melatonin is a timing signal, not a sedative — it tells your clock the hour rather than switching you off
• Retail doses are typically ten to fifty times physiological, on the assumption that more is stronger
• Sleep medicine guidelines advise against melatonin for ordinary insomnia, and put behavioural therapy first for every adult
• Supplement content has been measured from 83% below label to 478% above, with unlisted serotonin in a quarter of products
• It genuinely helps with jet lag, delayed sleep phase and shift work — used at a small dose, at the right hour, for a defined period
• A fixed wake time, morning light, and getting out of bed when you are not sleeping outperform anything in the jar
• Snoring, gasping and daytime sleepiness point at sleep apnoea, which needs testing rather than sleep hygiene

Before you act on any of this

I am a pharmacist and a nutritionist. I am not your doctor, and this article is general information rather than advice about you specifically. Nothing here is a reason to start, stop or change a prescribed medicine, and prescribed sleeping tablets in particular should never be stopped abruptly. If you are pregnant, taking an antidepressant, or managing a chronic condition, check before adding melatonin to anything. What this article can do is tell you which questions are worth asking at your next appointment.

Sources

• Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults (American Academy of Sleep Medicine, 2017)
• Management of Chronic Insomnia Disorder in Adults: A Clinical Practice Guideline From the American College of Physicians (Annals of Internal Medicine, 2016)
• Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content (J Clin Sleep Med, 2017)