What Is Melatonin? The Hormone, the Supplement, and What the Label Means

Melatonin (the chemical name is N-acetyl-5-methoxytryptamine) is produced from the amino acid tryptophan, by way of serotonin, inside the pineal gland. Its release is gated by light: the retina reports ambient brightness to a cluster of cells in the hypothalamus called the suprachiasmatic nucleus, which acts as the body's master clock, and that clock tells the pineal gland to start releasing melatonin as the evening darkens. Levels climb through the evening, peak in the middle of the night, and fall toward morning. Researchers sometimes call it the hormone of darkness for exactly this reason: it is a signal that it is night, not a sedative in the way a sleeping drug is.

This is why bright screens and overhead lighting late in the evening matter so much in every sleep-hygiene guide you have ever read. Light, and blue-shifted light in particular, suppresses the body's own melatonin release. The supplement does not switch the pineal gland on or off; it adds a measured amount of the same molecule from outside, on a schedule you choose, which is why timing matters as much as the number on the label. The how melatonin works page goes deeper on the clock and the receptors.

Early melatonin supplements were extracted from animal pineal tissue, and that is one reason older references carry warnings about contamination. That era is over. The melatonin in every product in our catalog is either synthesized in a laboratory, which yields a molecule chemically identical to the one your body makes, or extracted from plant sources, which some makers market as "phytomelatonin" or "plant-based." Labels that say vegan or vegetarian are usually telling you two things: the melatonin is not animal-derived, and the capsule or gummy contains no gelatin. NOW Melatonin 3 mg veg capsules, at $4.27 for 60 (verified via the Amazon Creators API on September 5, 2026), is a typical example of the vegetarian-capsule format.

Because it is a supplement, the manufacturing standard that applies is the FDA's current good manufacturing practice rule for dietary supplements, not the stricter drug rule. Reputable makers go further and pay for third-party verification: a USP Verified mark, an NSF mark, or a similar seal means an outside lab has checked that the bottle contains what the label says. That matters more for melatonin than for most supplements. A 2017 analysis published in the Journal of Clinical Sleep Medicine tested 31 melatonin products and found actual melatonin content ranging from 83 percent below the labeled amount to 478 percent above it, with several products also containing measurable serotonin. Where a listing states a verification mark, we point it out; where it does not, we say so.

In the United States melatonin is sold under the Dietary Supplement Health and Education Act of 1994. Under that law the FDA does not review a supplement for safety or effectiveness before it is marketed; the maker is responsible for the product and its label, and the FDA can act once a product is on the market if it proves unsafe or mislabeled. That is why every bottle carries the standard sentence: "These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease." We repeat it on every product page because it is true, not because it is boilerplate.

The same molecule is treated very differently elsewhere. In the United Kingdom and much of the European Union melatonin is a prescription medicine, and the licensed product there is a 2 mg prolonged-release tablet indicated for adults over 55. Australia moved a low-dose form to pharmacy-only status. None of those countries changed the chemistry; they drew the regulatory line in a different place. For an American buyer the practical consequence is that the label's directions and cautions are the maker's, the amounts are the maker's, and the person qualified to say whether melatonin belongs in your routine, at what amount, and alongside which medications, is a doctor or pharmacist.

Every melatonin product carries a Supplement Facts panel, and four lines on it decide what you are actually buying. First, the serving size: gummies in particular are often labeled per two gummies, so a "10 mg" jar may deliver 5 mg per piece. Second, the amount per serving, which is printed in milligrams (mg) or micrograms (mcg); 1 mg equals 1,000 mcg, so a 300 mcg capsule is 0.3 mg, a tenth of a 3 mg tablet. Third, the other ingredients line, which is where sugar, sugar alcohols, gelatin, colors and flavors live. Fourth, the directions, which tell you the timing the maker intends: fast-dissolve and liquid labels commonly direct use 20 to 30 minutes before bedtime, and time-release labels describe a release over several hours.

Blends add a fifth line. A product like OLLY Sleep lists 3 mg of melatonin alongside L-theanine and botanicals, at $16.35 for 70 gummies (verified via the Amazon Creators API on September 5, 2026); the panel tells you the amount of each. Read the whole panel before comparing prices, because a cost-per-night figure only means something when the amount per serving is the same on both sides. Our dosage chart lays out what the labels in our catalog state, format by format.

One molecule, a dozen delivery forms. The table below is the quick orientation; each format has its own ranked guide in the best melatonin hub. Amounts are the labeled amounts on the catalog products we link, and timing is how the labels phrase it, not a recommendation.

Prices are the live Amazon price verified via the Amazon Creators API on September 5, 2026 and should be treated as hedged. The format question that comes up most is speed versus duration: immediate-release forms are about falling asleep, and time-release forms are marketed for staying asleep. We say marketed for, because the format claim on the box is the maker's, and the how long melatonin lasts page explains what is actually known.

It is not a sedative-hypnotic. Prescription sleep drugs and the over-the-counter antihistamine sleep aids (doxylamine, diphenhydramine) work by different mechanisms, carry a Drug Facts label rather than a Supplement Facts panel, and are regulated as drugs. Melatonin is a timing signal; many people describe the effect as a gentle nudge rather than a knockout, and the published literature describes modest average effects on how long it takes to fall asleep. It is also not a vitamin, despite sharing a shelf with them: your body makes it, and taking more than your body needs does not build a reserve.

It is not proven to work better at higher amounts. This is the misconception that does the most damage. Amounts sold on Amazon run from 300 micrograms to 20 milligrams, a nearly seventy-fold range, and higher amounts are associated with the complaint owners report most often: next-day grogginess. Many sleep clinicians favor the lowest effective amount, often cited as 0.5 to 3 mg, and we report that as general guidance, not a prescription. The how much melatonin page covers the reasoning and what the labels direct.

Four groups should talk to a professional before the first serving, and the labels themselves say so. Children: the American Academy of Pediatrics advises talking to a pediatrician before giving melatonin, keeping gummies out of reach, and using the lowest amount. Pregnancy and nursing: consult a doctor; we make no product recommendation. Anyone on medication: melatonin can interact with blood thinners, immunosuppressants, blood-pressure medication and diabetes medication, so ask a pharmacist. Older adults: lower amounts are often favored and next-day grogginess is the common complaint. And nobody should drive after taking it.

Two safety pages go deeper: melatonin side effects lists what the NIH and the labels describe, and is melatonin safe for kids covers the pediatric guidance and the poison-control numbers that made child-resistant packaging a real buying criterion. Read those before the ranked guides, not after.