Does Melatonin Expire? Is Expired Melatonin Safe, and Does It Still Work?

Yes, melatonin expires. It slowly loses strength over time, faster in heat and light, and gummies can spoil if they're kept somewhere damp. Melatonin a little past its date is unlikely to harm you, but it may not work as well. If a tablet is crumbling, a gummy has turned sticky or hard, or anything smells, looks or tastes different, throw it out.

It's easy to find an old bottle of melatonin at the back of a drawer and wonder whether it's still any good. Here's what the date on the label means, what happens to melatonin as it ages, why gummies go off sooner than tablets, and how to store it so it lasts.

What the date on a melatonin bottle means

In the US, supplements don't have to carry an expiration date at all. The FDA's guidance for supplement makers says the manufacturing rules don't require one, but a company that does put a date on its label should have data to support it. So a jar with no date isn't breaking any rule. Go by when you bought it and when you opened it instead.

You'll see the date written a few ways: "Exp", "Best by" or "Use by". On supplements they mean much the same thing: the maker expects the product to contain what the label says, at full strength, up to that date, as long as it has been stored the way the label asks.

Does expired melatonin still work?

It may still work, just less reliably. Expiration doesn't flip a switch: the amount of melatonin in each dose drifts down gradually, and nobody can tell you exactly how much is left in an old jar.

Lab studies show what speeds that up. Melatonin dissolved in liquid breaks down faster in light and warmth, and keeps better cold and in the dark, as a 2020 study of melatonin in solutions and juices found. Solid forms hold up better: in one stability study, melatonin capsules stayed within specification for 18 months. Research on stored medicines points the same way. In a US government program that tests military drug stockpiles, 88 percent of batches kept their quality at least a year past the printed date, but results varied from batch to batch, and those were medicines kept in controlled storage and tested one by one, not supplements in a kitchen drawer.

There's a second reason not to count on an old bottle. Melatonin labels are often inaccurate even when the product is fresh. A 2017 Canadian study in the Journal of Clinical Sleep Medicine tested 31 melatonin supplements and found the actual content ranged from 83 percent below to 478 percent above the label. A 2023 research letter in JAMA found 22 of 25 melatonin gummy products were inaccurately labeled. Add time and poor storage on top of that and an expired dose is anyone's guess.

Is expired melatonin safe?

For most healthy adults, melatonin that's a little past its date is unlikely to be dangerous. The main known problem is that it gets weaker. The bigger risk is the product itself going off, which is far more likely with gummies and liquids than with tablets:

• Mold or a sour smell on gummies that have been kept somewhere damp
• Gummies that melted and set again, which means they've been through heat
• Cloudy or separated liquid melatonin, or a changed smell

Any of those means it goes in the trash, whatever the date says.

Can you take expired melatonin?

If it's only a little past its date, looks and smells normal and has been stored well, most people can. What you shouldn't do is take extra to make up for an old bottle. You can't know how much strength it has lost, and if it has lost very little, a double dose is simply a bigger dose, with a higher chance of feeling groggy the next morning or of unusually vivid dreams. If an old bottle isn't working, replace it rather than taking more.

Do melatonin gummies expire faster?

Gummies are the form most likely to change, though there's no published research on how fast melatonin itself breaks down inside one. Gummies are made with sugar, water and gelatin or pectin, so they react to their surroundings in a way a dry tablet doesn't. In heat they soften, stick together or melt. In damp air they can turn tacky or grow mold. Left open in dry air they harden. A gummy whose texture has changed has been stored badly, whatever the date says. Tablets and capsules are the steadiest forms, and liquids should be kept capped and out of the light. That's a storage point, not a reason to avoid gummies: whether a gummy works depends on what's in it, as we explain in are gummy supplements effective.

Signs your melatonin has gone bad

• Gummies that are sticky, hard, sweating, melted or fused together
• Any spots of mold, or a sour or musty smell
• Tablets that are crumbling, discolored or spotted
• A liquid that has changed color, turned cloudy or separated
• The jar was left in a hot car, a steamy bathroom or a sunny window for a long time
• The date has passed and you can't remember when you opened it

How long does melatonin last once opened?

There's no universal number, because it depends on the form and how it's kept. As a rule, a well-stored bottle is good until the date printed on it. Once it's open, keep the lid tight, leave any drying packet in the jar, and try to finish it within a reasonable time rather than keeping it for years. If your label gives a "use within" time after opening, follow that.

How to store melatonin

Heat and light speed up melatonin's breakdown, and moisture is what spoils gummies, so the aim is to keep it away from all three:

• Somewhere cool, dry and dark, like a kitchen cupboard away from the stove, or a bedroom drawer.
• Not in the bathroom. Shower steam is enough to make gummies go sticky.
• Not in the car or on a sunny windowsill, where heat and light do the most damage.
• Lid tight, every time. Leave any drying packet in the jar.
• No need for the fridge unless your label says so. Cold helps melatonin in liquids, but for gummies and tablets, taking a cold jar in and out of the fridge can draw moisture inside.
• Out of children's reach. Melatonin gummies look and taste like sweets, and the 2023 JAMA letter noted a sharp rise in calls to US poison control centers about children swallowing melatonin.

How to throw out old melatonin

Don't flush it. The FDA's advice for disposing of unused medicines works for supplements too: use a drug take-back site if there's one near you, or mix the tablets or gummies with something unappealing, such as used coffee grounds or cat litter, seal it in a bag and put it in the household trash.

Our sleep gummy, and keeping it fresh

Our Chamomile Sleep Gummies are made in small batches in Holmes County, Ohio. Each Blackberry gummy contains 10 mg of melatonin with 150 mg of L-theanine, 87 mg of magnesium bisglycinate and 23 mg of chamomile, every amount printed on the jar. Like any gummy, it keeps best with the lid closed in a cool, dry place, so the bedroom drawer is a better home for it than the bathroom cabinet. If you're new to melatonin, you can cut a gummy in half for about 5 mg and adjust from there, as we explain in is 10 mg of melatonin too much, and follow the directions on your jar.

Frequently asked questions

Can you take melatonin after the expiration date?

If it's only a little past the date, has been stored well and looks and smells normal, it's unlikely to harm you, but it may be weaker. Don't take more to make up for it; replace the bottle instead.

Does melatonin lose potency over time?

Yes, gradually. Heat and light speed it up, and damp air spoils gummies, which is why storage matters as much as the date.

Can expired melatonin make you sick?

The melatonin itself is unlikely to, but a spoiled product can. Throw out gummies with mold, a sour smell or a changed texture, and any liquid that looks or smells different.

Do melatonin gummies go bad in the heat?

Yes. Heat softens and melts gummies, and they can fuse together or sweat. A hot car is one of the quickest ways to ruin a jar.

Does melatonin need to be refrigerated?

Not unless the label says so. A cool, dry cupboard or drawer is better than the fridge for most tablets and gummies.

How long is melatonin good for?

Until the date on the bottle, if there is one and it's been stored as the label asks. After opening, keep it sealed and finish it within a reasonable time.

Why doesn't my old melatonin work anymore?

It may have lost strength, or your sleep problem may have changed. If fresh melatonin doesn't help either, look at timing first (our guide to how long melatonin lasts covers when to take it), then your routine, and see what actually helps you sleep.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease. This article is general information and not medical advice. Talk to your healthcare provider before taking melatonin, particularly if you are pregnant or nursing, take prescription medication, or are considering it for a child. If trouble sleeping persists, speak to your doctor.