Serotonin: Role, Benefits and Natural Tips to Boost Your Mood

Serotonin (5-hydroxytryptamine) is a neurotransmitter. It transmits a chemical message from one neuron to another. Over 90% of total serotonin is produced by enterochromaffin cells in the gut and then stored in blood platelets; the remainder comes from the raphe nuclei in the centre of the brainstem. Its biosynthesis takes place in two stages: hydroxylation of tryptophan (an essential amino acid) to 5-hydroxytryptophan (5-HTP), followed by decarboxylation to serotonin. This pathway is particularly dependent on Vitamin B6. Serotonin does not cross the blood-brain barrier; the brain must therefore produce it locally from circulating tryptophan.

Here are the main described effects of serotonin: 

• Regulation of mood and anxiety: Activation of 5-HT1A receptors promotes emotional stability, whilst low levels are linked to sadness and rumination.

• Sleep-wake cycle: A direct precursor of melatonin, serotonin modulates the onset of sleep and the quality of REM sleep.

• Appetite control: It curbs the craving for fast-acting carbohydrates after meals and contributes to the feeling of fullness.

• Intestinal motility: It triggers peristalsis and reduces the sensation of bloating; hence its nickname, the ‘enteric hormone’.

• Vascular functions and coagulation: Released by platelets, it causes transient vasoconstriction following an injury.

Dopamine and serotonin are complementary neurochemicals that influence our behaviour. Whilst dopamine signals reward and drives us to act, serotonin is associated with lasting satisfaction and with impulse control. The two pathways overlap in the striatum, the prefrontal cortex and the hippocampus, which are key areas for motivation and mood.

An excess of dopamine is associated with restlessness and compulsive behaviour, and a balance with serotonin appears to matter here. Serotonin is also thought to influence dopamine release, which may help moderate the pursuit of pleasure. Maintaining a balance between the two therefore supports mental wellbeing.

Here are the main causes of a serotonin deficiency. 

Reduced Tryptophan Intake

A diet low in high-quality protein (eggs, pulses, turkey, soya) limits the raw materials needed for synthesis.

Chronic Stress and Inflammation

Cortisol diverts tryptophan metabolism towards the kynurenine pathway, to the detriment of the serotonergic pathway. At the same time, intestinal inflammation disrupts enteric production.

Lack of Light

Sunlight stimulates both serotonin synthesis and its conversion to melatonin at night; shorter winter daylight hours therefore reduce this neurotransmitter.

An Unbalanced Gut Microbiota

Certain bacterial strains (e.g. Bifidobacterium infantis) positively regulate tryptophan metabolism; dysbiosis can therefore reduce the availability of serotonin.

Specific Treatments or Conditions

Long-term corticosteroid treatment, vitamin B6 deficiency, malabsorption disorders and excessive alcohol consumption are among the factors identified.

When the body lacks serotonin, certain signs appear: 

• Depressive mood and irritability: Loss of zest for life, negative outlook, impulsiveness

• Anxiety and night-time rumination: Difficulty falling asleep, frequent waking

• Cravings for sweet foods or binge eating: Seeking quick carbohydrate-based compensation

• Mild cognitive impairment: Fluctuating attention, slowed working memory

• Reduced libido and premature ejaculation in men, reduced sexual desire in women

• Morning fatigue not explained by an organic condition

• Tension-type headaches and hypersensitivity to pain

• Functional digestive disorders: Alternating diarrhoea and constipation, bloating

It is possible to boost serotonin production by adjusting your diet: 

• Foods rich in tryptophan: whole eggs, pumpkin seeds, mature Parmesan, fermented soya, turkey and salmon; these provide the amino acid required for biosynthesis.

• Fruits and nuts that contain the valuable neurotransmitter directly : ripe bananas (≈ 15 µg/g), pineapple and kiwi; nuts up to 155 µg/g.

• Complex carbohydrates: a portion of whole grains eaten as part of the same meal facilitates the uptake of tryptophan into the brain via insulin.

• Vitamin B6, magnesium and zinc: chickpeas, sesame seeds and cocoa; these cofactors optimise key enzymes.

A comprehensive strategy also includes: 

• Morning light exposure: 20 minutes of natural light is often enough to boost central production.

• Aerobic exercise: 30 minutes of brisk walking or cycling raises plasma serotonin levels by an average of 50 per cent in the hours that follow.

• Breathing techniques and meditation: Cardiac coherence, mindfulness, yoga; these lower cortisol levels and release the ‘happiness hormone’.

• Regular sleep: A consistent bedtime, limited screen time; melatonin is derived directly from serotonin.

Natural Plant-Based Melatonin – Dietary Supplement

This plant-based melatonin, extracted from St John’s wort and encapsulated without chemical solvents, provides 0.95 mg per capsule – or 1 mg from two capsules – a dosage designed to help you fall asleep more quickly or minimise the effects of jet lag. Melatonin is a hormone the pineal gland releases at night to synchronise the sleep-wake cycle. This 99.5% organic formula uses HPMC capsules and prebiotic acacia gum, is free from controversial additives, carries no risk of dependency, and is manufactured in France. Not recommended during pregnancy or for those with autoimmune diseases; occasional use is recommended.

Triple Magnesium – Dietary Supplement

This jar of 120 capsules offers a triple source of magnesium — highly bioavailable bisglycinate, marine magnesium and organic sea lettuce extract — which together provide 300 mg of magnesium per day from three capsules, representing nearly 80 per cent of the recommended daily intake. This mineral, an electrolyte that regulates fluid balance and nerve function, supports energy levels, muscle contraction and bone density. Vegan formula, additive-free, packaged in France, with optimal digestive tolerance, suitable for a forty-day course of treatment, and ideal for periods of stress, fatigue, or training. 

Here is a suggested routine to maintain stable levels of the ‘happiness hormone’: 

1. 07.30 – Get some sunlight and practise deep breathing for three minutes.

2. 08.00 – Breakfast: soya yoghurt, porridge, chia seeds, banana.

3. 12.45 – Balanced lunch: red lentil dahl, brown rice, rocket salad.

4. 3.00 pm – Ten-minute walk + snack of dried fruit and nuts.

5. 6.30 pm – Moderate exercise session (cycling, swimming or tai chi).

6. 8.00 pm – Light dinner: spinach omelette, buckwheat bread, kiwi; followed by ten minutes of screen-free reading before lights out.

Tryptophan should not be taken on its own as a supplement at high doses, especially in combination with an SSRI antidepressant (selective serotonin reuptake inhibitor), as this can be unsafe. If you have persistent low mood, speak to a healthcare professional before self-medicating.

Take a whole-system view: serotonin doesn't act alone, but as part of a network with dopamine, GABA and the gut microbiome. A varied diet, daily natural light and moderate physical activity are a safe, sustainable way to support this neurotransmitter. Supplements can help, provided you take them with guidance and within recommended limits. Listening to your body, adjusting your habits gradually, and checking for interactions with any medication is a sound long-term approach.

Stéphanie is a pharmacist (since 2010) and holds a PhD in molecular biology (since 2012). Passionate about writing, she has produced medical content for nearly 15 years. Her goal is to make information accessible and easy to understand, without ever sacrificing scientific accuracy.