Short answer: feeling tired is not the same as being ready to sleep. Sleep onset needs several conditions to line up at once — enough accumulated sleep pressure, a circadian window that is open, a falling core body temperature, and enough inhibitory signalling to quieten the arousal system. Being exhausted while none of those are in place is the normal explanation for lying awake.
The two-process model
Sleep timing is governed by two interacting systems, formalised by Borbély and revisited in the Journal of Sleep Research (2016).
Process S is homeostatic sleep pressure: adenosine accumulates across waking hours and builds the drive to sleep. Process C is the circadian rhythm, the roughly 24-hour oscillation determining when your body is biologically prepared for sleep.
Most sleep-onset problems are a failure in one of the two: not enough adenosine (late naps, low daytime activity, or caffeine occupying the receptors), or circadian misalignment (irregular timing, late light, shift work).
Core body temperature
Sleep onset depends on core temperature falling from its daytime peak, which happens through peripheral vasodilation radiating heat from the skin.
This is why a warm bath before bed helps rather than hinders. A systematic review and meta-analysis in Sleep Medicine Reviews (2019) found passive body heating one to two hours before bed shortened sleep onset latency — by driving blood to the skin so core temperature drops faster afterwards. A previous version of this page attributed that finding to a different journal and attached a precise ten-minute figure; the source and the framing have been corrected.
Anything holding core temperature up works against onset: a warm room, alcohol, or hard training close to bedtime.
Melatonin is a timing signal, not a sedative
Melatonin does not cause sleep. It signals darkness, and levels begin rising roughly two hours before habitual sleep onset.
Evening light suppresses it. Gooley and colleagues (2011) in the Journal of Clinical Endocrinology & Metabolism found that exposure to ordinary room light before bedtime suppressed melatonin and shortened its duration — not exotic lighting, just a normally lit room.
This page previously attached that finding to a paper about growth hormone secretion. The claim was right; the citation was not, and it has been replaced.
The GABA pathway and racing thoughts
Lying awake with a busy mind is usually a downregulation failure: the ascending arousal system has not been adequately inhibited by GABAergic signalling.
Magnesium supports GABA receptor function and modulates NMDA receptors on the excitatory side, so adequate magnesium status is a precondition for that transition working normally. Glycine — the carrier in magnesium glycinate — contributes separately: preclinical work in Neuropsychopharmacology (2015) found its sleep-promoting effect is accompanied by a fall in core body temperature via NMDA receptors in the suprachiasmatic nucleus.
If the racing mind is driven by stress rather than by magnesium status, the lever is evening cortisol — see High Cortisol at Night.
Lemon balm, passionflower and valerian, graded honestly
Lemon balm is studied for inhibiting GABA-T, the enzyme that breaks down GABA, with mostly small human trials.
Passionflower has the most-cited result of the three: Akhondzadeh and colleagues (2001), in the Journal of Clinical Pharmacy and Therapeutics, ran a pilot double-blind randomised trial comparing passionflower extract with oxazepam in generalised anxiety and found comparable reductions in anxiety scores. It was a small pilot in a clinical population, and this page previously cited it to the wrong journal and the wrong paper entirely.
Valerian is the weakest of the three. This page previously said it had shown "consistent effects" on sleep onset latency; systematic reviews have in fact found inconsistent results, with the positive trials tending to be smaller and methodologically weaker. We have corrected that. Full grading in Natural Sleep Aids: What Has Evidence and What Doesn't.
All three are in the Reishi Relax Gummies, chosen to act on different points of the wind-down pathway rather than to stack sedatives.
Frequently Asked Questions
Quick answers to the questions readers most often ask.
Why is it hard to fall asleep even when tired?
Tiredness reflects accumulated sleep pressure, but onset also needs an open circadian window, a falling core body temperature, and adequate inhibitory signalling to quieten the arousal system. If any of those are missing, you can feel exhausted and still lie awake.
What helps you fall asleep faster?
Dim the lights well before bed, since ordinary room light suppresses melatonin. Keep the bedroom cool, around 16 to 19 degrees. Take a warm bath one to two hours before bed. Move the caffeine cut-off to eight to ten hours before sleep. Keep wake time fixed.
Does melatonin help you fall asleep?
Melatonin is a timing signal rather than a sedative. It has good evidence for circadian problems such as jet lag, shift work and delayed sleep phase, and much weaker evidence for improving sleep quality when your clock is already aligned. Every AE·ORA rest product is melatonin-free.
What is the two-process model of sleep?
It describes sleep as regulated by two interacting systems: Process S, the homeostatic drive built by adenosine accumulating during waking, and Process C, the circadian rhythm determining when sleep is biologically favoured. Onset happens when both align.
What causes a racing mind at night?
Usually a failure to downregulate: the GABAergic system has not adequately suppressed the ascending arousal system. Contributors include elevated evening cortisol, late light exposure, stimulants and inadequate magnesium status. Addressing evening cortisol and light usually does more than any supplement.
References
Every reference below has been verified against PubMed.
- Akhondzadeh S et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther. 2001.
- Gooley JJ et al. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. J Clin Endocrinol Metab. 2011.
- Kawai N et al. The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuropsychopharmacology. 2015.
- Borbély AA et al. The two-process model of sleep regulation: a reappraisal. J Sleep Res. 2016.
- Haghayegh S et al. Before-bedtime passive body heating by warm shower or bath to improve sleep: a systematic review and meta-analysis. Sleep Med Rev. 2019.
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.
