When I Actually Suggest Melatonin… (Almost Never)

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Most people who come to Kat are already on melatonin — and one of the first things she does is figure out whether they actually need it. The gap between how people take melatonin and how their body uses it tends to be where the confusion lives. This video walks through three things that change the picture, including the one that makes it difficult to evaluate whether melatonin is doing anything at all.

  • Why melatonin deficiency as the primary driver of sleep problems is less common than most people think
  • Dim light melatonin onset (DLMO) — what it is, why it varies between individuals, and why timing matters as much as dose
  • What melatonin does well (circadian timing) versus what it doesn’t (staying asleep)
  • Why long-term melatonin use can make it harder to identify what’s actually driving your sleep problems
  • Three practical steps if you’ve been on melatonin for months or years and are still struggling with sleep

Before You Refill That Melatonin: Three Things That Change the Picture

One of the most common things I hear in early conversations is some version of this: “I’ve been taking melatonin for a while. I’m not sure it’s doing much — but I’m also not sure I want to stop.”

That uncertainty is understandable. Melatonin is everywhere. It’s affordable, it’s labeled “natural,” and the dosing instructions on the bottle make it feel like something you can simply take and expect results. So people start it. Months or years later, they’re still taking it — sleep still not where they want it, still not sure what melatonin is doing, still not sure how to find out.

What I’ve found, working with people on sleep, is that this confusion almost always traces back to the same gap: melatonin is usually presented as a standard supplement with standard dosing, as though it works the same way for everyone. The reality is far more individual. There are three things, specifically, that tend to get missed — and each one changes how you think about whether melatonin belongs in your approach at all.

Most Adults Can Produce Melatonin Just Fine

The assumption people most often bring to melatonin is that their sleep is difficult because their melatonin is low. That if sleep feels off, the body isn’t making enough — and the supplement fills the gap.

In most healthy adults, that assumption doesn’t hold up.

Melatonin is produced by the pineal gland, a small structure in the brain, in response to darkness. As light levels drop in the evening, the retina sends a message that allows melatonin release to begin. This is a tightly regulated process. In most adults, the capacity for production is intact.

What does affect melatonin production is light exposure. Artificial light — especially in the blue-spectrum range — delays the onset of melatonin release. Bright light late in the evening can push back when the body begins producing melatonin by 90 minutes or more. That’s a timing issue. The underlying production capacity is typically there. The input the body receives has been altered; the production machinery itself tends to remain intact.

There’s also a widespread belief that aging automatically reduces melatonin — that at some point, production simply declines and supplementation becomes necessary. The research is more nuanced than that framing suggests. Changes can occur with age, but they’re not universal. Some 70-year-olds produce more melatonin than people in their 30s. The picture is individual. Aging doesn’t write a predictable melatonin arc for everyone.

This matters practically. If your body is producing melatonin adequately — and that capacity simply hasn’t been given the right environmental conditions to express itself — then adding melatonin from outside isn’t addressing the underlying driver. What tends to happen instead is that the supplement becomes a kind of placeholder: something you continue taking without knowing what you’re getting from it, while whatever is driving the sleep difficulty goes unexamined.

And there’s a compounding problem I’ll come back to — long-term melatonin use makes it harder to see what’s actually happening with your sleep.

Your DLMO — Why the Standard Dosing Time Is Often Off

Even in cases where melatonin is relevant, most people are taking it at the wrong time.

This is where a concept called dim light melatonin onset — DLMO — becomes essential to understand.

Your DLMO is the point in the evening when your body naturally begins releasing melatonin under low-light conditions. It’s not the moment you feel sleepy. It’s the physiological marker that precedes that feeling — typically occurring one to three hours before habitual sleep onset, corresponding with a drop in core body temperature and the early onset of drowsiness that follows.

What standard dosing guidance doesn’t account for is that DLMO varies between individuals. Meaningfully. Two people who want to fall asleep at the same time can have DLMOs that differ by an hour or more. This variation is driven by individual circadian architecture — genetic chronotype, light history, current sleep schedule, and other factors that are specific to you.

The standard instruction — take melatonin 30 to 60 minutes before your target bedtime — is a rough estimate that accounts for none of this. In practice, it tends to be too early for some people and too late for others.

Here’s what that means in concrete terms. If you take melatonin at 9:30pm because you want to be asleep by 10pm, but your natural DLMO is at 8pm, you’re adding melatonin after your body has already begun its own release. You’re adding to something already underway — and the effect on circadian timing is minimal. If your DLMO falls at 11pm, you’re taking the supplement two hours before your body would naturally begin producing it, which can push back when you feel sleepy rather than move it earlier.

There’s also a directional consideration that tends to go unexamined: are you trying to fall asleep at the same time you usually do, or are you trying to move your sleep window earlier or later? Melatonin can, under the right conditions, help advance or delay circadian timing — but only when taken at a time that corresponds to where you want your body clock to move. Getting that right requires knowing your DLMO.

This is why two people can take the same dose at the same clock time and have entirely different outcomes. Their internal timing differs. The hormone lands in a different part of each person’s circadian cycle. Without knowing your own DLMO, you’re working from a rough estimate — and the estimate may not be serving you.

The Distinction Between Falling Asleep and Staying Asleep

Understanding what melatonin does mechanistically makes it far easier to assess whether it fits the problem you’re trying to address.

Melatonin is a circadian timing hormone. Its function is to communicate darkness to the body — to indicate that the biological night has begun, and allow the cascade of processes associated with the sleep phase to proceed. It does this broadly: the brain, the cardiovascular system, the digestive tract, and other organs all have melatonin receptors and use this input to coordinate their own rhythms with the overall sleep-wake cycle.

Where melatonin has its strongest applicability is in timing-related problems. Jet lag is the textbook case. You’ve crossed time zones and asked your body clock to adjust rapidly. Melatonin, taken at the right time relative to your destination’s light-dark cycle, can support that adjustment. Delayed sleep phase — where the body consistently wants to fall asleep later than the schedule allows — is another area where the evidence has some backing, when timing is used thoughtfully.

Where melatonin has limited utility is sleep continuity — staying asleep through the second half of the night.

In my work, a large proportion of the individuals who come to me on melatonin started it because they wake up in the middle of the night and can’t return to sleep. This is a common experience, especially in adults over 40. But that pattern — waking after sleep onset, or WASO in sleep research — tends to reflect something other than circadian timing. Sleep continuity in the second half of the night is more closely tied to sleep architecture, cortisol timing, the balance between sleep stages, and how the nervous system transitions between them. The evidence for melatonin reducing wake-after-sleep-onset is limited.

This is a useful distinction. If someone started melatonin hoping it would help them stay asleep, and it hasn’t — that mismatch is one to examine. The hormone may simply not match the problem.

What Long-Term Melatonin Use Obscures

There’s one more piece that often doesn’t come up in standard melatonin conversations.

When someone has been taking melatonin for months or years — especially at the doses found in most supplements, which tend to run far higher than what the body produces on its own — it becomes difficult to see what their sleep looks like without it. The exogenous hormone, introduced from outside, creates interference that makes it hard to get an accurate read on what the body is doing independently.

In my work, when someone comes to me with ongoing sleep difficulties and they’ve been on long-term melatonin, getting an unobstructed view of their sleep is often one of the first things on the list. Stopping melatonin may or may not be the answer — the point is that you can’t accurately evaluate what’s driving the sleep issues when an outside hormone is in the picture.

That baseline — what sleep looks like without the supplement — tends to be informative. It often changes the direction of the conversation. Sometimes sleep changes in ways that point toward something specific. Sometimes it doesn’t change much, which is its own useful data point.

What long-term melatonin use tends to do, primarily, is obscure that picture. Taking it for months without resolving the original problem is one to look at — rather than something to continue by default.

Three Practical Steps If Melatonin Hasn’t Been Working

Get specific about what you’re trying to address. Is the issue falling asleep — sleep onset? Or staying asleep once you’re there? Melatonin has more applicability to the first. If your primary issue is waking in the second half of the night and lying there unable to return to sleep, that pattern points toward something other than circadian timing, and melatonin is probably not the tool that will move it.

If you’ve been on melatonin for months or years without consistent improvement, consider discussing a gradual reduction with a specialist. The purpose is to get an accurate view of what your sleep is doing beneath the supplement — because that information changes what you examine next. How your sleep responds during that process is data. It tells you something.

If you’re considering starting melatonin, understand the timing before you begin. The standard 30–60 minutes before your target sleep time may not align with your individual physiology. Your dim light melatonin onset — the point when your body expects to begin producing melatonin — differs between people even when the target sleep time is the same, and the standard recommendation tends to be too early for most, though it may fit a smaller subset. Starting with a lower dose — 0.5mg is closer to the physiological range than the 3–10mg commonly sold — and paying close attention to what changes gives you more useful information than jumping to a higher dose.

Melatonin in the Right Context

In the right context — circadian timing issues, jet lag, delayed sleep phase, dosing that reflects your individual physiology — melatonin has genuine applicability. The research supports it for those specific uses. The problems tend to emerge when it’s used as a default for sleep difficulties, without a clear match between the mechanism of the hormone and the mechanism of the problem.

Understanding how your body uses melatonin — when it produces it, what it’s designed to support, how your individual timing compares to standard guidance — moves you from a place of trying things and hoping, toward a place of testing something specific and knowing what you’re looking for. That’s a different starting point. And in my experience, it leads to more useful answers.

If you want a more structured way to examine your sleep from this kind of mechanism-based angle, I put together a free 40-part circadian guide that I use with every client before we look at hormones, testing, or anything deeper. It covers factors most people have never considered — kidney circadian rhythm, chrononutrition, bedroom air quality, and 36 more. The Circadian Mastery Protocol is free and linked here: https://thelongevityvault.com/circadian-mastery-protocol

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