How Much Melatonin Should You Take? Dose Guide | Slumbr

For most sleep-timing purposes, the evidence supports 0.3 to 1 mg of melatonin, a fraction of what is in the bottles commonly sold. Melatonin does not work like a painkiller, where a bigger dose does more. Above roughly 1 mg the effect on your body clock stops growing, but the side effects keep going. If you have been taking 5 or 10 mg and waking up foggy, the dose is the most likely reason.

Key takeaways

The useful range for shifting sleep timing is 0.3 to 1 mg, taken at the right hour.
Beyond about 1 mg, a larger dose does not reliably produce a larger shift in the body clock. It mostly produces morning grogginess.
The 3, 5 and 10 mg products widely sold internationally are not the clinical standard anywhere.
Prolonged-release melatonin is a separate, prescription-only medicine in South Africa with its own approved dose. It is not a bigger version of the low-dose product.
If the dose is not the problem, the timing usually is. And if neither is, the diagnosis probably is.

Why more is not better

Your pineal gland releases a small amount of melatonin each evening. It is a signal, not a sedative: the body's way of announcing that darkness has begun. Roughly 0.3 mg taken by mouth is enough to raise blood melatonin into the range your own body produces at night. That is what a dose is for. It imitates the natural night-time signal at the hour you want your body to think it is night.

A 10 mg dose does not make that signal ten times clearer. It makes it far higher than anything your body produces naturally, and it makes it last much longer. Melatonin is cleared quickly, which is why the natural signal falls away before morning. Load in ten times the amount and there is still melatonin circulating when your alarm goes off. That is the "melatonin hangover" people describe: a night-time signal that overstayed.

The receptors involved behave the way most receptors do. Once they are occupied, adding more of the molecule does not produce more effect. This is why the dose-response for shifting the body clock flattens out early, and why the studies that established melatonin's usefulness as a chronobiotic used doses that sound implausibly small to anyone who has shopped for it.

So what should you actually take?

For the timing uses melatonin is genuinely good at (jet lag, adjusting to a shift roster, a sleep phase that has drifted later than you want), 0.3 to 1 mg is the working range.

Start at the bottom. If 0.5 mg does nothing after several nights taken at the right time, the answer is almost never to escalate to 5 mg. It is to check the timing, and then to question whether melatonin is the right tool at all. Those two checks solve far more cases than a dose increase.

There is one important exception, and it is a different medicine entirely.

Prolonged-release melatonin is not the same thing

South Africa has a registered prolonged-release melatonin tablet, a Schedule 4 prescription-only medicine. Its approved professional information sets out a specific and quite narrow use:

2 mg once daily, for adults aged 55 and over
taken one to two hours before bedtime, and after food
for the short-term treatment of primary insomnia characterised by poor quality of sleep
for up to thirteen weeks

Three details are worth pulling out. First, the approved information states plainly that efficacy in patients younger than 55 has not been demonstrated. This is not a general-purpose adult sleeping tablet. Second, the tablets must be swallowed whole; crushing or chewing them destroys the prolonged-release mechanism, which is the entire point of the formulation. Third, the "after food" instruction is part of the approved directions, not an optional nicety.

So when someone says "2 mg is the standard melatonin dose," they are usually confusing this prescription medicine with the low-dose immediate-release products. They are designed to do different jobs. One imitates a brief evening signal to move a clock. The other releases slowly across the night in an age group whose own melatonin production has declined. You cannot substitute one for the other by adjusting the number of tablets.

What about the 5 mg and 10 mg products on the shelf?

You will find 3 mg, 5 mg and 10 mg melatonin products for sale in South Africa, generally labelled as supplements. Their existence is not evidence that those are sensible doses. International manufacturing conventions put 10 mg in a bottle, not clinical dosing studies.

If a high-dose product is what you have:

Do not assume you must take a whole one. For immediate-release tablets, splitting is often possible, though accuracy at these small amounts is poor.
Never split, crush or chew a prolonged-release tablet. It is engineered to release slowly and breaking it defeats that.
If your product is a gummy or a liquid, splitting the dose accurately is difficult. That is a real practical argument for buying a lower-strength product rather than dividing a strong one.

Higher doses also carry a specific risk beyond grogginess. Melatonin's effect on the body clock depends on when it arrives relative to your own melatonin rhythm. A large dose lingers long enough to spill across that window, which means it can nudge your clock in a direction you did not intend.

When the dose is not the problem

The most common reason melatonin disappoints is not that the amount was wrong. It is that the person taking it does not have a body-clock problem.

Melatonin moves the timing of sleep. If you go to bed at a perfectly normal hour and lie there with a racing mind, your sleep is not mistimed. Your nervous system is aroused, and no dose of a timing hormone fixes that. If you have been sleeping badly at least three nights a week for three months or more, with real daytime consequences, that pattern meets the clinical definition of chronic insomnia, and the recommended first-line treatment is CBT-I (cognitive behavioural therapy for insomnia), not a supplement.

This is why we start patients with a pattern assessment rather than a product. Whether melatonin is the right tool, and at what dose and hour, depends entirely on which pattern you actually have.

Who should get medical advice before taking any dose

Speak to a doctor first if you are pregnant or breastfeeding, if the melatonin is intended for anyone under 18, if you have an autoimmune condition or liver problems, or if you take other medicines. That last group includes antidepressants, epilepsy medicines, blood thinners, and hormonal contraception, all of which have documented interactions with melatonin. And if your sleep problem comes with loud snoring, witnessed pauses in breathing, or heavy daytime sleepiness, the priority is assessment for a sleep disorder rather than any dose of anything.

Frequently asked questions

How much melatonin should I take for sleep? For sleep-timing problems, 0.3 to 1 mg taken at the correct hour. Melatonin is not a sedative and does not have a "sleep dose" in the way a sleeping tablet does. If your problem is chronic insomnia rather than mistimed sleep, melatonin is usually the wrong medicine at any dose.

Is 10 mg of melatonin too much? It is far more than the evidence supports for shifting the body clock, and it is the dose most likely to leave you groggy the next morning. It is not typically dangerous in a healthy adult, but there is no clinical reason to take it.

Can I cut a melatonin tablet in half? An immediate-release tablet, often yes, though dividing accurately at these small amounts is difficult. A prolonged-release tablet, no: it must be swallowed whole, because crushing or chewing destroys the slow-release mechanism.

Should I increase the dose if it stops working? Almost never. Escalating the dose is the most common mistake in melatonin use. Check the timing first, then reconsider whether your sleep problem is a timing problem at all.

Does a higher dose help you fall asleep faster? Not meaningfully. Melatonin's effect on sleep onset is modest at any dose, because it works on when your body expects to sleep rather than on sedating you.

Is the 2 mg prescription tablet just a stronger version? No. It is a different formulation with a different release profile, approved for a specific group (adults aged 55 and over) for short-term use. It is not interchangeable with low-dose immediate-release melatonin.

How Much Melatonin Should You Take? The Dose Most People Get Wrong