- Insomnia is a symptom, not a diagnosis. Something specific is keeping you awake, and in almost every case we can measure it.
- Waking at 3am is a blood sugar and cortisol signature. Glucose drops overnight, cortisol rises to correct it, and cortisol wakes you.
- Cortisol is supposed to be a curve, not a level. A single morning reading tells you almost nothing — four points across a day tells you everything.
- Sleep depends on nutrients. Magnesium, B6 and iron are all required to build serotonin and melatonin. Short on any of them and the pathway stalls.
- Sleep apnoea is dramatically under-diagnosed, including in slim women, and no supplement compensates for an airway that closes.
Insomnia is a symptom, and something is causing it
What we find with patients is that being handed a sleep aid closes the investigation before it starts.
A sedative will put you unconscious. That is not the same as sleeping. Sleep is an active, structured process — cycles of deep slow-wave sleep where physical repair happens, and REM where memory and emotion are processed. Most sedatives suppress one or both while producing the appearance of sleep.
So the question I want answered is not how to make you unconscious. It is why the process that should happen automatically has stopped happening.
In practice the answer is nearly always one of five things: an inverted cortisol rhythm, blood sugar that falls overnight, a nutrient the pathway depends on, a hormone that has changed, or an airway that closes. Each of them looks identical from the outside. Each of them needs a different fix.
The cortisol curve, and why you wake at 3am
Cortisol has a bad reputation it does not entirely deserve. It is your wake-up hormone, and the problem is almost never how much you have — it is when you have it.
A healthy cortisol curve peaks about thirty minutes after waking, falls steadily through the day, and reaches its lowest point around midnight. That fall is what permits melatonin to rise. Cortisol and melatonin are on a seesaw: melatonin cannot come up until cortisol goes down.
After years of sustained stress that curve flattens or inverts. Cortisol is low in the morning — which is why you cannot function before coffee — and elevated in the evening, which is why you are wired at eleven at night and cannot switch off.
Then there is 3am specifically, which is such a consistent pattern that it is almost diagnostic on its own. You have not eaten for hours. Blood glucose falls. Your body treats a falling glucose level as an emergency and releases cortisol and adrenaline to raise it — and those are the hormones that wake you up. You come awake at 3am, alert, often with your heart going, and you cannot work out why.
That is not anxiety. That is a metabolic event, and it usually resolves when blood sugar is stabilised through the day and the evening meal contains enough protein and fat to carry you overnight.
What we measure before we treat
The ten levers that restore sleep
Ranked by how often the problem sits there and how quickly correcting it changes the night.
Stabilise Blood Sugar, Especially at Dinner
The 3am waker's single most useful change. Protein and fat at the evening meal carry glucose through the night so cortisol is not called on to rescue it. What we find with patients is that this alone resolves a large share of middle-of-the-night waking within a fortnight.
What the evidence showsNocturnal hypoglycaemia triggers a counter-regulatory release of cortisol and catecholamines to restore glucose, and those hormones produce arousal. Protein and fat at the evening meal slow gastric emptying and blunt the overnight glucose fall.Rebuild the Cortisol Curve
Morning daylight within thirty minutes of waking anchors the rhythm at the top. Reducing evening stimulation, caffeine cut-offs by early afternoon, and genuine wind-down anchor it at the bottom. The curve is trainable, and it usually takes about three weeks.
What the evidence showsMorning bright light exposure is the strongest zeitgeber for the circadian system and advances the cortisol awakening response. Caffeine has a half-life of approximately five to six hours, so afternoon intake measurably raises evening cortisol.Correct Magnesium
Required for GABA receptor function and for the enzymes that build melatonin. Magnesium glycinate at 300–400 mg in the evening is one of the most reliably useful things we recommend — and RBC magnesium is the test, because serum will look normal regardless.
What the evidence showsA double-blind placebo-controlled trial of magnesium supplementation in elderly patients with insomnia found significant improvements in sleep time, sleep efficiency and sleep onset latency. Magnesium modulates GABA receptor activity.Screen for Sleep Apnoea Properly
Under-diagnosed in general and severely under-diagnosed in women, who present with insomnia and fatigue rather than loud snoring. If the airway closes forty times an hour, no nutrient protocol compensates. This deserves a proper test, not an assumption.
What the evidence showsObstructive sleep apnoea is significantly under-diagnosed in women, who present with insomnia, fatigue and mood symptoms rather than classic snoring. Untreated apnoea fragments sleep architecture regardless of hours in bed.Address Progesterone in Perimenopause
Progesterone works on the same receptor system as anti-anxiety medication, and it falls before estrogen does. New insomnia in a woman in her early forties is a hormonal event far more often than a psychiatric one.
What the evidence showsProgesterone metabolites including allopregnanolone are positive allosteric modulators of the GABA-A receptor, the same target as benzodiazepines. Progesterone decline precedes estrogen decline in the menopausal transition.Correct Iron
Low ferritin causes restless legs and fragmented sleep, and iron is a cofactor in serotonin production. This is one of the most common findings in women who cannot stay asleep and have been told it is stress.
What the evidence showsIron deficiency is an established cause of restless legs syndrome, and iron is a cofactor for tryptophan hydroxylase in serotonin synthesis. Ferritin below 75 ng/mL is associated with symptom severity.Light Discipline
Bright light in the morning, dim light after sunset. Blue light in the evening suppresses melatonin directly. This is free, it is unglamorous, and it moves the curve more than most supplements.
What the evidence showsEvening blue-wavelength light suppresses melatonin secretion in a dose-dependent manner. Morning bright light exposure advances circadian phase and improves sleep onset in controlled studies.Cool the Room and the Body
Core temperature has to fall for sleep to initiate. A cool room, and a warm bath ninety minutes before bed, work by the same mechanism — the bath causes a temperature drop afterwards that triggers sleep onset.
What the evidence showsSleep onset is preceded by a fall in core body temperature. Passive body heating one to two hours before bed accelerates the subsequent temperature drop and has been shown to shorten sleep onset latency.Support Serotonin and Melatonin Production
B6, tryptophan, magnesium and adequate protein are the raw materials. Rather than supplying melatonin from outside indefinitely, we would prefer to give your body what it needs to make its own.
What the evidence showsMelatonin synthesis requires tryptophan, vitamin B6 as a cofactor for the decarboxylase step, and magnesium. Dietary tryptophan availability influences serotonin and downstream melatonin production.Botanicals, Chosen for the Pattern
Ashwagandha where cortisol is elevated at night. Passionflower or lemon balm for a racing mind at sleep onset. Valerian for sleep maintenance. These are different herbs for different problems, and picking the wrong one simply does nothing.
What the evidence showsAshwagandha has randomised placebo-controlled evidence for reducing serum cortisol and improving sleep quality. Valerian and passionflower have trial data for sleep onset and maintenance respectively, with different mechanisms.What patients commonly experience under our care
When patients receive the proper guidance, here is what they commonly experience under our care.
- The first week — falling asleep. Magnesium and an evening routine usually shorten sleep onset first. Patients describe getting to sleep in twenty minutes rather than ninety.
- Weeks 2–3 — staying asleep. This is where stabilised blood sugar shows. The 3am waking becomes less frequent, then stops, and people begin sleeping through for the first time in years.
- Weeks 3–6 — the morning. As the cortisol curve rebuilds at the top, waking becomes easier and the first hour of the day stops requiring caffeine to negotiate.
- Weeks 8–12 — the panel confirms it. Cortisol rhythm restored across all four points. RBC magnesium normalised. Ferritin climbing. Fasting insulin down. We retest, because the numbers should move alongside how you feel.
If you have been lying awake at three in the morning for months or years, please do not accept a sedative as the answer to a question nobody investigated. Schedule a consultation and let my team find what is actually keeping you awake. You will be cared for by a team who will not stop until the root cause of every one of your health issues has been found and addressed.
A four-point cortisol rhythm, the nutrients sleep depends on, and a proper apnoea screen. Your discovery call is free.
Common questions
Why do I wake up at 3am every night?
It is one of the most consistent patterns we see. Overnight your blood glucose falls, and if it falls far enough your body releases cortisol and adrenaline to raise it — and those hormones wake you. That is why people describe waking suddenly, alert, sometimes with a racing heart. It is a metabolic event rather than anxiety, and it usually resolves when blood sugar is stabilised through the day and the evening meal contains enough protein and fat.
What blood tests should I get for insomnia?
A four-point cortisol rhythm rather than a single morning reading, fasting insulin and HbA1c, RBC magnesium, ferritin, a full thyroid panel, vitamin D and B12, and progesterone in women. A proper sleep apnoea screen belongs in that list too, because it is dramatically under-diagnosed.
Is melatonin safe to take long term?
Melatonin is a hormone rather than a herbal sedative, and taking it indefinitely means supplying from outside what your body should be producing. Short-term use has a place, particularly for circadian shifts and travel. Our preference is to find out why your own production stopped — usually cortisol timing, magnesium, B6 or light exposure — and correct that.
Can perimenopause cause insomnia?
Yes, and it is one of the earliest signs. Progesterone acts on the GABA receptor system, the same one targeted by anti-anxiety medication, and it declines before estrogen does. New sleep disruption in a woman in her late thirties or early forties is frequently the first sign of the hormonal transition.
Is there a sleep doctor near Nashville who looks at root causes?
We are at 329 S. Royal Oaks Blvd in Franklin, about twenty minutes south of downtown Nashville and minutes from Brentwood and Cool Springs. We run cortisol rhythm testing, the full nutrient panel and hormone work, and we coordinate a formal sleep study where apnoea is suspected.
- Hirotsu C, Tufik S, Andersen ML. Interactions between sleep, stress, and metabolism: from physiological to pathological conditions. Sleep Science. 2015;8(3):143–152. PMC4688585
- Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt on metabolic and endocrine function. The Lancet. 1999;354(9188):1435–1439.
- Abbasi B, Kimiagar M, Sadeghniiat K, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences. 2012;17(12):1161–1169. PMC3703169
- Baker FC, de Zambotti M, Colrain IM, Bei B. Sleep problems during the menopausal transition. Nature and Science of Sleep. 2018;10:73–95.
- Allen RP, Picchietti DL, Garcia-Borreguero D, et al. Restless legs syndrome and iron. Sleep Medicine. 2014;15(8):860–873.
This article is educational and reflects the published literature as of August 2026. It is not a diagnosis or a treatment recommendation for any individual, and any decision about your care belongs in a conversation with a licensed practitioner who has seen your history and your labs.