Introduction
Happiness is a universal pursuit that has fascinated humans for centuries. Neurochemical
messengers such as dopamine, endorphins, serotonin and oxytocin are quite often referred
to as the ‘happy hormones.' These chemicals play a crucial role in shaping our emotional
and mental well beings.
Dopamine
Dopamine is one of the most extensively researched neurotransmitters in the human brain.
Known as the ‘reward chemical,’ it plays a critical part in regulating various functions such as
reward, motivation and learning.

Dopamine is synthesised from amino acid tyrosine through a series of enzymatic steps
including tyrosine hydroxylase and DOPA decarboxylase enzymes. Once dopamine is
synthesised, it is stored in areas of the brain like the ventral tegmental area and substantia
nigra and is released and carried through the various pathways. Dopamine becomes
effective when it binds to the dopamine receptors located on the surface of the targeted
cells.

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However, imbalance in dopamine levels can cause serious impacts on one’s health.
Excessive dopamine activity is linked to conditions like schizophrenia resulting in
hallucinations, delusions, and impaired cognitive functioning. Meanwhile, low dopamine
levels are associated with conditions such as Parkinson's disease and depression.

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Endorphins
Endorphins are the endogenous opioids of the human body. These hormones help relieve
pain, reduce stress and improve one’s quality of life.

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There are three types of endorphins: α endorphins, β endorphins and γ endorphins.
However, β endorphins are studied most due to its influence on nociception. All three are
short peptides derived from the precursor, proopiomelanocortin, which is synthesised in the
pituitary gland and hypothalamus.

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Scientists extensively research their effects during rigorous physical activities. Endorphins
are known as ‘runner’s high,’ an expression used to refer to a short-lasting feeling of
euphoria that occurs during or after exercising intensively.

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Serotonin
Serotonin is a monoamine neurotransmitter which regulates and stabilises mood by allowing
one to feel happier, calmer, more emotionally secure and focused.

Serotonin is essentially found in the brainstem of the nervous system and the
gastrointestinal tract of the body. From the brainstem, it projects its effects throughout the
brain and the rest of the nervous system. Scientists have found a total of seven different
serotonin receptor families in which they vary from what substances they bind to and the
effects they mediate. Serotonin is also widely known to be involved in the digestion of food. It
is proven that the lining of the gut produces about 90% of the body’s serotonin, whereas the
brain only contains 10%. Serotonin helps hasten digestion and get rid of irritating and
harmful substances.

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Low levels of serotonin may cause depression for which antidepressants are used as
treatment. One the most prescribed drug is called SSRI. It blocks the reuptake of serotonin
elevating and prolonging its action in the synaptic space. Nevertheless, there are many side
effects to these drugs as serotonin is used for a wide range of bodily processes.

Oxytocin
Oxytocin, also known as the ‘love hormone’ is associated with trust, empathy and social
bonding. It is released in response to low intensity stimulation of the skin such as touching
and stroking. Research states that oxytocin is released more in females than in males which
is essentially why females get emotionally bonded very strongly.

Oxytocin is a neuropeptide which is primarily produced by the hypothalamus of the brain and
is transported through axons to the posterior lobe of the pituitary gland. From there, the
chemicals get secreted into the bloodstream of the body.

It is widely known to be involved with breastfeeding and childbirth. During labour, the
stretching of the cervix sends signals to the hypothalamus to release more of oxytocin. The
hormones bind to the receptors in the uterus which causes rhythmic uterine contractions
promoting further labour. The secretion continues until childbirth is complete. Furthermore,

the suckling of the nipple causes release of oxytocin during breastfeeding. The
neurochemical induces the contractions of the myoepithelial cells of the breasts which
causes the ejection of milk.

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Conclusion
Understanding the science of happy hormones provides valuable insights into the intricacies
of human emotions and overall happiness. Serotonin, dopamine, oxytocin, and endorphins
work in harmony to regulate our mood, motivation, social bonds, and stress response.
Achieving a balanced blend of these hormones is essential to experience happiness.

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By Su Lei  (Abby) Waddy