What is behind Sleep & Insomnia
Not hours — architecture. What restores you is the order of the night: deep slow-wave sleep early for physical repair, REM weighted late for memory and emotion. A full eight hours in the wrong shape leaves you unrestored. Evidence A — Human trial evidence.
GABA — the brain's principal inhibitory neurotransmitter, the source of calm and restful sleep. Evidence A — Human trial evidence.
Melatonin — the hormone of biological night that entrains the body clock and opens the gate to sleep. Evidence A — Human trial evidence.
Adenosine A1 signaling — the molecule that builds through waking hours to create sleep pressure and helps insulate nerve fibers. Evidence A — Human trial evidence.
The wakefulness and appetite peptide, and a genuine two-way system. A systematic review of 30 studies found orexin neurons activated by low glucose and suppressed by high — a counter-regulatory loop, not a one-way arrow. Evidence A — Human trial evidence.
The hypothalamic–pituitary–adrenal axis and its hormone cortisol — the body's central stress-and-recovery command. Evidence A — Human trial evidence.
The cystine–glutamate exchange that supplies antioxidant building blocks while tuning excitatory neurotransmission. Evidence A — Human trial evidence.
Melatonergic circadian entrainment — the alignment of the internal clock with the day–night cycle. Evidence A — Human trial evidence.
Serotonin — the neurotransmitter of mood and satiety, and the precursor the body converts to melatonin for sleep. Evidence A — Human trial evidence.
The mast cell — the histamine-laden sentinel behind allergic and hypersensitivity reactions. Evidence A — Human trial evidence.
The chemistry of wanting, not of liking. Dopamine sets how much effort a goal feels worth — which is why its loss reads as apathy long before it reads as sadness. More is not better: the same system that drives pursuit drives compulsion. Evidence A — Human trial evidence.
The master inflammatory switch — indispensable to defend against threat, corrosive when it never stands down. Evidence B — Preclinical.
The smallest amino acid, and an inhibitory neurotransmitter in its own right. Its sleep evidence rests on polysomnography â objective sleep-onset latency shortened. Capped by T4: one Japanese group, no independent replication. Evidence B — Preclinical.
Inhibitory glycine-receptor tone and core-temperature lowering that support sleep onset (distinct from GABA). Evidence B — Preclinical.
Evidence on these pathways
Adenosine A1 → Alertness / Arousal. “After microdialysis perfusion of A1 receptor antisense in the basal forebrain, spontaneous levels of sleep-wakefulness showed a significant reduction in non-rapid eye movement (REM) sleep with an increase in wakefulness.” — A1 Receptor and Adenosinergic Homeostatic Regulation of Sleep-Wakefulness: Effects of Antisense to the A1 Receptor in the Cholinergic Basal Forebrain (OpenAlex renders 'A1Receptor' without a space). Journal of Neuroscience 2003;23(10):4278-4287. doi:10.1523/jneurosci.23-10-04278.2003 | PMID 12764116
Circadian Rhythm → Cognition. “Circadian disruption resulted in pronounced deficits in learning and memory paralleled by marked reductions in hippocampal cell proliferation and neurogenesis.” — Experimental 'Jet Lag' Inhibits Adult Neurogenesis and Produces Long-Term Cognitive Deficits in Female Hamsters. PLoS ONE, 2010, vol 5, e15267. doi:10.1371/journal.pone.0015267
Dopamine → Melatonin. “Through α1B-D4 and β1-D4 receptor heteromers dopamine inhibits adrenergic receptor signaling and blocks the synthesis of melatonin induced by adrenergic receptor ligands.” — Circadian-Related Heteromerization of Adrenergic and Dopamine D4 Receptors Modulates Melatonin Synthesis and Release in the Pineal Gland. PLoS Biology, 2012, volume 10, e1001347. doi:10.1371/journal.pbio.1001347
Dopamine → Mood (Positive Affect). “Boosting dopamine also increased happiness resulting from some rewards.” — Dopaminergic Modulation of Decision Making and Subjective Well-Being. Journal of Neuroscience, 2015, 35(27), 9811-9822. doi:10.1523/JNEUROSCI.0702-15.2015 | PMC4495239
Formulas that act on these pathways
Acts on 13 of these pathways: Sleep, GABA, Melatonin, Adenosine A1, Orexin, HPA Axis / Cortisol, Cystine–Glutamate Antiporter, Circadian Rhythm, Serotonin, Mast Cell, Dopamine, NF-κB, Glycine.
Acts on 8 of these pathways: Sleep, GABA, HPA Axis / Cortisol, Cystine–Glutamate Antiporter, Serotonin, Mast Cell, Dopamine, NF-κB.
Acts on 8 of these pathways: Sleep, GABA, HPA Axis / Cortisol, Cystine–Glutamate Antiporter, Circadian Rhythm, Serotonin, Dopamine, NF-κB.
Acts on 6 of these pathways: Sleep, HPA Axis / Cortisol, Cystine–Glutamate Antiporter, Circadian Rhythm, Serotonin, NF-κB.
Acts on 6 of these pathways: Sleep, GABA, HPA Axis / Cortisol, Cystine–Glutamate Antiporter, Serotonin, NF-κB.
Acts on 5 of these pathways: Sleep, GABA, HPA Axis / Cortisol, Cystine–Glutamate Antiporter, Serotonin.
What this page does not claim
This page names the pathways involved and the published evidence on each. It does not claim that any formula treats, cures or prevents Sleep & Insomnia. A pathway opens here only on graded, published evidence, under a standard fixed before the evidence was gathered, and every figure above carries its grade.
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.