Yellow label of a melatonin supplement bottle describing 3mg chewable tablets with peppermint flavor

Writing Realistic Melatonin Overdose Scenes

Wait…what? Isn’t melatonin just a natural sleep aid? How could it be dangerous enough to cause an overdose?

Well, that’s a trick question.

Melatonin is a natural hormone created in the body and regulates sleep-wake cycles. It’s been used to help with mild insomnia, jet lag, and day-night cycles for night-shift workers and people that are blind. Think of it as a ‘dowsiness aid,’ but not as a true ‘sleeping pill.’

Melatonin is also a chemical, eventhough it’s often referred to as a ‘natural product.’ And too much of any chemical can be bad, including the risk of serious overdose.

Yellow label of a melatonin supplement bottle describing 3mg chewable tablets with peppermint flavor

The truth about unregulated supplements

Melatonin is marketed as a ‘dietary supplement.’ Did you know that supplements are not regulated by the Food and Drug Administration (see this FDA bulletin) in the same way that drugs are—at least not before they’re on the market? Makers of ‘dietary supplements’ can sell products without submitting the kinds of rigorous safety or efficacy studies required for drugs.

The FDA only restricts a dietary supplement after marketing if:

  • Problems (such as illness or injury) are reported or
  • Random testing finds a concern or
  • The company claims the supplement does what actual drugs are proven to do (diagnose, cure, mitigate, treat, or prevent a disease). Once a company claims their product creates any of those effects, the rules change and the product will be held to the legal standards of regulated drugs. But as long as the claims remain very general, such as ‘supports restful sleep,’ the supplement remains unregulated.

What does it mean to be an unregulated ‘supplement’?

It means the manufacturer is responsible for overseeing the integrity and content of their own products. For honest companies, this may be a realistic expectation. But for less-honest ones, this hasn’t always worked in the consumer’s best interest. Here are just a few examples:

  • Some supplements don’t contain what the label states
    • Melatonin tablets have been found that contain waaaaay more (almost 500% more!) of the supplement than stated on the label (see here).
    • Tablets have also been found with no melatonin at all. Instead, they have contained other unlabeled chemicals, such as CBD.
  • Contaminated supplements have caused illness
    • Vitamin D drops and other supplements from one company were recalled after consumers developed serious infections (see here and here). The products were suspected to be contaminated with bacteria. Unfortunately, a number of people had to get sick before the trend triggered a product recall.

So…is melatonin risky or not?

If the supplement really has melatonin in it (at the amount on the label), there’s often little risk to adults after taking a typical tablet or two. We don’t really know what dose is appropriate to mimic the normal melatonin in the body, but a tablet (or two) for some adults will hardly be noticed, as it may gently allow the user to fall asleep easier. Others report a lot of drowsiness, sometimes with a bit of a sleepy hangover effect the next day, after just a single tablet. But who knows what was actually in that tablet?

On the other hand, children tend to get drowsier than adults from melatonin supplements. With the content of melatonin tablets (or gummies) potentially inconsistent, it shouldn’t be suprising that children can have unpredictable responses to doses.

So…how can melatonin be used believably to create a page-turner for your readers?

Here are a few ideas to consider (and a few to avoid) to get you started:


  • Realistic options:
    • During Covid 19, the number of melatonin overdoses escalated. Some were thought to be from :
      • Kids being around the house more, leading to more access to medicine cabinets;
      • Depression from lifestyle effects of Covid (lock-down isolation, fear of covid infection, constant news reports of death tolls) leading to increased suicide attempts;
      • Severe insomnia leading to extra pills being taken with the false assumption that a higher dose might be more helpful and a natural drug is ‘safe.’
    • Plausible scenarios include:
      • Attempted (and failed) suicide by an adult character
        • The character can realistically develop mild to moderate sleepiness, but should not be described as unwakeable or in a coma. It’s realistic for the character to wake a few hours later, with a slight headache or sluggish hangover the next day.
      • An accidental overdose by your character’s child
        • The kiddo can eat too many melatonin gummies— after all, they look like candy. This young character can realistically have no symptoms (except for a belly ache from all those gummies) or become extremely drowsy. Over the last few years, an increasing number of children with melatonin overdoses have even needed emergency treatment with ventilators to help them breath until the melatonin wears off. A few unfortunate cases have lead to death in some young children.
  • NOT realistic: Death in adults from a melatonin overdose
    • Most melatonin overdoses cause no (or few) symptoms, except in children (see above).
      • In adults, a few cases have resulted in severe drowsiness, but writers should not count on this as a plot device, unless the reader already knows the character is over-sensitive to this kind of supplement. Again, a coma is not a believable plot twist for an adult character using melatonin…unless the pills were tainted (see below).

Contaminants leading to illness or death

  • Realistic:
    • Some natural supplements have been contaminated with fungus or bacteria, heavy metals, or unlabeled ingredients, sometimes causing death. See this article on the potential risks of supplements due to the lack of regulation.
    • For an eye-opening look at what may actually be in that little melatonin sleeping pill, click here.
  • Not realistic:
    • Fentanyl-tainted melatonin bought from a store
      • Street drugs contaminated with fentanyl is a growing concern, but there’s not a realistic case for fentanyl-tainted store-bought supplements.
        • Over-the-counter supplements have safety seals and tamper-evident tops. It would be difficult to create and hide fentanyl contamination in this type of product. An antagonist would have to really go through a lot of effort to create this kind of danger. There are much easier ways for him to go about his evil plotting!
        • There have been no cases of store-bought natural supplements contaminated with dangerous opioids—such as fentanyl.
    • Fentanyl-laced melatonin bought from a drug dealer
      • There wouldn’t be any realistic market for drug dealers to sell melatonin. Street drugs that are tainted with fentanyl are usually those that cause a high (like heroin, counterfeit Xanax), help with pain (oxycodone), or result in stimulation (cocaine, amphetamines). They are generally illicit drugs or diverted prescription drugs, as opposed to over-the-counter supplements, vitamins, or medications that are easily purchased. (If you really want to use fentanyl in your plot, here are a few tips).

Hopefully, you have a lot of ideas swimming around for new plot twists and how to realistically use melatonin in your story. But if you’d like a few more sample scenarios to practice with or information on a wide array of other drug perils to consider for a scene, check out THE GRIM READER: A PHARMACIST’S GUIDE TO PUTTING YOUR CHARACTERS IN PERIL (in EBook and paperback).

Other melatonin references:

Happy Plotting!

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