⏱ 4 min read
Sleep is probably the least understood physiological function in popular culture: for decades it was treated as "lost" time that could be cut to gain productivity, a conception that modern neuroscience has completely demolished; sleep is an active state in which the brain consolidates memory, clears toxic metabolites via the glymphatic system, restores synaptic connections, and in which the entire organism regulates hormones, repairs tissues, and resets circadian systems. Chronic sleep deprivation is associated with practically all modern chronic diseases and with increased all-cause mortality, which makes sufficient sleep one of the most cost-effective lifestyle interventions for long-term health.
Sleep is regulated by two complementary systems:
Homeostatic system: during wakefulness, brain adenosine accumulates and produces increasing "sleep pressure"; deep sleep clears the adenosine and restores wakefulness. Caffeine acts by blocking adenosine receptors, which explains its wake-promoting effect and why consuming it in the afternoon can prevent falling asleep at night.
Circadian system: the hypothalamic biological clock (suprachiasmatic nucleus) generates rhythms of approximately 24 hours that synchronize sleep, body temperature, hormone secretion, and other processes with day-night cycles. The main external synchronizers are light (especially bright morning light and nighttime darkness), food, physical activity, and temperature.
Both systems must be well coordinated for optimal sleep.
Sleep is organized into cycles of 90-120 minutes that repeat 4-6 times per night, alternating between non-REM sleep (with its 3 stages) and REM sleep. Each stage has specific functions:
Selective deprivation of any stage produces specific deficits: too little deep sleep is associated with poorer physical recovery, hormonal disruption, and even a higher risk of Alzheimer's disease (beta-amyloid accumulation); too little REM is associated with poorer emotional regulation, learning problems, and greater irritability.
Before thinking about sleep supplements, it is worth securing the basics:
Melatonin (0.5-3 mg, 30-60 minutes before bedtime): especially useful for sleep-onset insomnia associated with circadian misalignment (jet lag, shift work, phase delay). Low doses (0.3-1 mg) are usually more effective than high ones. In older adults with reduced endogenous levels it can be particularly useful.
Glycine (3 g before bedtime): improves subjective sleep quality and lowers core body temperature, facilitating sleep onset.
Magnesium (200-400 mg, glycinate or malate): improves sleep quality, especially in people with subclinical deficiency.
L-theanine (200 mg): promotes relaxation before sleep.
Tryptophan (1-3 g): precursor of serotonin and melatonin; useful in mild insomnia.
Valerian: with modest support, subjective improvement greater than objective.
Passionflower, lemon balm, lavender (Silexan): mild anxiolytics useful when insomnia is associated with anticipatory anxiety.
Apigenin (from chamomile or other sources): mild GABAergic effects.
Chronic insomnia (more than 3 months despite adequate sleep hygiene), suspected sleep apnea (heavy snoring, witnessed breathing pauses, excessive daytime sleepiness, refractory hypertension), significant restless legs syndrome, insomnia associated with depression or clinical anxiety, or any persistent sleep disturbance with functional impact require specialized medical evaluation (sleep medicine, psychiatry, pulmonology as indicated). Nutritional self-intervention does not replace the diagnosis or treatment of specific sleep pathology.
Sleeping well is probably the individual health intervention with the best cost-effectiveness available; it is not optional or a "luxury" but a fundamental biological need; the combination of consistent schedules, sleep hygiene, stress management, adequate light exposure and, when useful, mild supplements (melatonin, glycine, magnesium) resolves most mild problems; pharmacological hypnotics (benzodiazepines, Z-drugs) have a place in specific situations but are not a sustainable solution for chronic insomnia, where CBT-I is clearly superior.
Information, not medical advice.