Melatonin, longevity and anti-ageing effects
Melatonin is a hormone produced by the pineal gland. Known for regulating sleep, its effects extend far beyond this primary role. With antioxidant, immunomodulatory and neuroprotective properties, it appears essential to understanding ageing and longevity. Its gradually declining secretion with age is accompanied by sleep disorders, metabolic imbalances and reduced vitality. Studying melatonin from an anti-ageing perspective helps explain how this molecule contributes to maintaining overall health.
The biology of melatonin
Melatonin is synthesised from tryptophan via serotonin, then released mainly at night. Its production is controlled by the light-dark cycle perceived by the retina. Darkness stimulates secretion, while light suppresses it.
Its role as a biological messenger makes it a central regulator of circadian rhythms. It affects sleep and many hormonal, metabolic and cellular processes.
Signs of melatonin deficiency
Melatonin production gradually decreases with age, but certain signs suggest significant deficiency: difficulty falling asleep despite fatigue, frequent night-time awakenings and fragmented sleep, reduced total sleep duration, reduced alertness and daytime drowsiness, mood changes (irritability, anxiety or depressive tendencies), loss of concentration and memory problems, weakened immunity with more frequent infections, and visibly accelerated skin ageing.
These symptoms are non-specific and should be assessed by a doctor, who may recommend testing or appropriate supplementation.
Melatonin and sleep
Melatonin directly contributes to falling asleep. It lowers body temperature and signals to the brain that night has arrived. It improves sleep quality and reduces the time taken to fall asleep.
In older people, reduced melatonin production causes lighter, fragmented and less restorative sleep. Deep sleep is essential for cellular repair, hormonal balance and memory consolidation.
Antioxidant and anti-inflammatory properties
Melatonin is one of the most powerful natural antioxidants. It neutralises free radicals and stimulates protective enzyme production. It therefore protects DNA, proteins and cell membranes against oxidative stress, a major factor in ageing.
It also acts on chronic inflammation, a characteristic of pathological ageing. By regulating inflammatory cytokine production, it limits inflammaging, a process responsible for many age-related diseases.
The functions of melatonin
Melatonin has multiple functions.
- Melatonin, the circadian clock and hormonal regulation: melatonin orchestrates the biological clock. It synchronises circadian rhythms regulating body temperature, cortisol and growth hormone secretion, and energy metabolism. Deficiency disrupts this balance, causing fatigue, hormonal disorders and accelerated ageing. This desynchronisation is particularly pronounced in people exposed to strong artificial light or irregular schedules.
- Melatonin and the immune system: melatonin modulates immune responses by strengthening defences against infections and reducing inflammatory overactivation. It therefore helps preserve functional immunity during ageing.
- Melatonin and cardiovascular health: melatonin improves vascular health by regulating blood pressure and protecting the endothelium. It also reduces lipid oxidation, a mechanism involved in atherosclerosis.
- Melatonin and the brain: through its antioxidant and neuroprotective action, melatonin reduces age-related neuronal damage. It improves nerve cell survival and could limit the progression of neurodegenerative diseases.
- Melatonin and skin: the skin has melatonin receptors and produces it locally. It contributes to ultraviolet protection, DNA repair and skin regeneration. Deficiency encourages wrinkles, loss of elasticity and a dull complexion.
- Melatonin and metabolism: melatonin influences insulin secretion and glucose sensitivity. Deficiency promotes type 2 diabetes and metabolic syndrome. Regular secretion helps maintain balanced metabolism and protects against premature ageing.
Melatonin and skin ageing
Melatonin, a key circadian rhythm hormone, plays a decisive role in skin homeostasis and ageing. It has powerful antioxidant effects, neutralising free radicals responsible for oxidative stress induced by environmental aggressors such as ultraviolet radiation, pollution and chronic stress. With age, the physiological decline in melatonin secretion impairs cellular repair mechanisms and accelerates collagen and elastin breakdown. This causes loss of firmness, wrinkles, reduced skin radiance and increased skin sensitivity.
Aesthetic medicine techniques to improve these skin changes include:
Mesotherapy: injections of vitamins, antioxidants and hyaluronic acid to stimulate cellular metabolism and improve skin hydration and radiance.
Photorejuvenation laser: stimulating collagen synthesis, improving skin density and correcting pigmentation irregularities associated with photoageing.
Skinboosters: injections of lightly cross-linked hyaluronic acid to restore deep hydration, suppleness and overall skin quality.
Superficial peels: controlled exfoliation promoting cell renewal, a more even complexion and fine line reduction.
Differences in secretion between men and women
Melatonin secretion differs between men and women. Several studies have shown that young women have slightly higher average levels than men, particularly during the follicular phase of the menstrual cycle. This is thought to relate to interactions between melatonin and oestrogens.
At menopause, falling oestrogen levels accompany a marked decrease in melatonin, partly explaining increased sleep disorders and night-time hot flushes in women over fifty. In men, the decline is more gradual but associated with andropause and a parallel decrease in testosterone.
These biological differences must be considered when prescribing, as sensitivity to supplementation may vary by sex and hormonal status.
The relationship between melatonin and nutrition
Nutrition strongly influences melatonin production. Its precursor, tryptophan, is an amino acid found in foods such as eggs, dairy products, nuts, seeds and some meats. A diet low in tryptophan may limit the body's ability to produce melatonin.
Furthermore, serotonin production, a key stage in melatonin synthesis, relies on sufficient B vitamins, magnesium and zinc. Deficiency in these micronutrients can therefore disrupt melatonin production.
Certain plants and foods naturally promote melatonin secretion, such as sour cherries, grapes, tomatoes and walnuts. These dietary sources contain small amounts of melatonin and may help improve circadian rhythm.
Finally, meal timing plays an important role. Very late dinners rich in fat or sugar disrupt night-time secretion. Conversely, a light dinner rich in tryptophan-containing proteins supports optimal production and better sleep.
Melatonin forms and dosages
Melatonin is available in several forms: tablets, capsules, oral solutions and sublingual sprays.
Immediate-release forms promote falling asleep and are indicated to reduce sleep latency.
Prolonged-release forms maintain stable levels overnight and are more suitable for people who wake frequently.
Dosage depends on age, patient profile and indication. In Switzerland and Europe, the most common therapeutic dose for sleep disorders ranges between 0,5 and 2 milligrams. In certain medical situations, higher doses may be used under supervision.
It should be taken around thirty minutes before bedtime. Self-medication is discouraged because an overdose or inappropriate use can disrupt the biological clock instead of restoring it.
Melatonin and ageing
Numerous studies have examined melatonin's impact on health and ageing.
Several meta-analyses confirm melatonin's effectiveness in reducing time to fall asleep and improving sleep quality, particularly in older people.
Experimental studies show that melatonin protects cells against oxidative damage and reduces apoptosis, helping slow cellular senescence.
Clinical studies have shown improved immune responses in older patients supplemented with melatonin.
Some research suggests reduced night-time blood pressure and an improved lipid profile with melatonin.
Pilot trials indicate fewer sleep disorders and improvements in certain cognitive functions in patients with Alzheimer's disease, although larger studies are needed to confirm these results.
In vitro and in vivo studies show that melatonin protects skin fibroblasts against ultraviolet damage and stimulates DNA repair.
Current research debates
Despite promising results, melatonin remains the subject of scientific debate. Some researchers consider current therapeutic doses too low to produce a genuine systemic effect, particularly in anti-ageing. Others emphasise that chronic supplementation could disrupt natural endogenous secretion over the long term.
Another debate concerns the actual extent of its effects. Although sleep benefits are firmly established, effects on longevity remain uncertain. Available studies are often small and short-term.
Finally, melatonin's role as an anti-ageing molecule raises an ethical question: should it be considered simple support for biological rhythms or genuine hormone replacement therapy? The coming years will probably provide more precise answers through the large clinical trials currently underway.
