When we fall in love it seems like our brain don't work in the usual way. We get sweaty palms, heavy breathing or feeling breathless, we can't think clearly, and it feels like we have butterflies in our stomach. Nevertheless, this feeling is wonderful. It can be triggered by something as simple as the meeting of eyes, touching of hands, listening to music or reading a book.

The little molecule phenylethylamine (PEA),PEA900, is the infatuation inducing stimulant. Together with dopamine and norepinephrine they can create a feeling of euphoria and uncertainty, resulting in insatiable desire. But unfortunately there is a limit due to the neurotransmitter bombardment over an extended time dulling the response. PEA is a natural chemical similar to amphetamine and dopamine, causing us the high experience by lovers.

We will now try to explain how this "love molecule" works.


A neurotransmitter is a substance that carry out the actual passage of of a signal across a synapse.

Moods and behaviour are largely influenced by the ratio of five central nervous system chemicals known as amines. These include; norepinephrine, epinephrine, serotonin, phenylethylamine (PEA) and dopamine. These neurotransmitters can be divided into two groups, the amines that excite the central nervous system (CNS) and those that inhibit or modulate that excitement.

Excitatory (fight and flight hormones)


Affects contractions of musclevessels. Increase in bloodpressure and heartrate. Temporarily increase of bloodsugar. Triggers anxiety
Picture of Epinephrine


Always present in the blood. Regulate the bloodpressure and distributes blood in the body. Triggers hostility and irritability.
Picture of Norepinephrine


Has a multiple regulatory role in the nervous system, neurotransmission included. Synthesised in the pineal glands, which is known to regulate the light-dark cycle in animals. Serotonin regulates sleep and wakefulness. Serotonin is also secreted by cells in the small intestines, where it regulates testinal peristalsis. Finally , seroronin is a potent vasoconstrictor that helps regulate bloodpressure. At increasing levels serotonin stimulates nervous tension, drowsiness, heart palpations, water retention and inability to concentrate and perform.
Picture of Serotonine



Modulates or off sets the negative effects of the excitatory hormones by inducing relaxation and mental alertness. The importance of dopamine in diseases seem to be associated with improper dopamine regulation. Deficiency of dopamine seem to cause Parkinson's disease, too muck of dopamine causes Schizofrenia.
Picture of Dopamine

PEA. Is a chemical that speeds up the flow of information between nerve cells. Is a mood elevator that makes us feel euphoric at low levels. (At higher levels it causes paranoia).

As we can see are adequate dopamine and PEA levels extremely important to balance the excitatory hormones for enhanced emotional stability.


L-phenylalanine is a precursor for PEA. Vitamin B6 is the key nutrient in the production of the beneficial biogenic dopamine and PEA. Vitamin B6 in the form of pyridoxine hydrochloride is biologically inactive. Once B6 enters a cell,enzymatic transfer of the g-phosphoryl group from ATP forms the coenzyme pyridoxal 5’-phosphat, PLP. This conversion to the active form requires magnesium and vitamin B2. PLP is a prostetic group for many enzymeS that catalyze a vareity of reactions involving amino acids. PLP is tightly bound to to the enzyme by many weak noncovalent interactions.

Picture of Phenylalanine Decarboxyalase + PLP + Mg + Vitamine B2 ---> Picture of Phenyl Ethyl Amine
Phenylalanine PEA

The carboxylgroup of phenylalanine is removed by decarboxylase and a hydrogen is added

The activity of PEA is largely determined by an enzyme known as monoamine oxidase (MAO). MAO is the chemical of risk takers. It is known to be 20% lower in women. This is the hormone which causes fear is to warn us of danger - not to make us afraid of danger. MAO is divided into two types. MAO type A deactivates the excitatory hormones while MAO type B deactivates dopamine and PEA. They can be inactivated by oxidative removal of their aminogroup by monoamineoxidase. An increase in type A MAO and a lower level of type B MAO is ideal for creation of emotional stability.

Progesterone and dihydro-testosterone increases type A activity and suppressing type B activity and therefore increasing biological levels of PEA (and dopamine)


As difficult as love is to define, its first flickers apparently begin in the prefrontal cortex, the section of your brain that enables you to anticipate the joy of being with a particul person, even one you ever met. If it´s powerful enough, this so called memory of the future engages the ancestral “fight and flight” response of the lower brain, which is responsible for such involuntary functions as stammering, tripping, drooling and laughing too loudly at someone else´s joke.

Endorphines fuel the chemical cocktail. Similar in structure to morphine, endorphines are perhaps best known for creating a blissful sense of calm in long distance runners. They leave lovers feeling similary tranquil, but not in the early going. During the initial stages of attraction, endorphines serve as a catalyst by triggering special cells in the midbrain to produce dopamine and PEA, powerful natural amphetamines. In the boot camp of romance, dopamine and PEA are the drill sergeant. They barks at the brain to select a plan of action, any plan.


Picture of Amphetamine Picture of Phenylethylamine
Amfetamine Phenylethylamine

As we can see PEA and amphetamine are very similar to each other. Some of the effects of amphetamine is increased energy, enhanced awakeness, less appetite, increased breathe and heart rate. Do you recognize this? It seems to be the same effects as that of PEA when we fall in love. An overcosumption of amphetamine and overproduktion of PEA leads to paranoia.


Last year the scientists Dr Peter Godfrey, Dr Lynette Hatherly and Emeritus Professor Ron Brown, University of Monash, announced that they had determined the arrangement of atoms that make up the PEA molecule.Recent research of the molecular shape of PEA could help advance treatment of mental illness, simplify chemical research and save drug companies millions of dollars. The researchteam said that the PEA breakthrough is especially important because it is one of the simplest neuro-transmitters and their research sucsess opens a path for future testing of related ,but more complex, chemicals associated with mentel illness. “Pea is structural relative of a series of hormones, some of which are linked to human motor system functions and the ocurrence of Parkinson´s disease, while others such as serotonin effectively dictate our emotional balance.” Dr Godfrey said.

If you have too high levels of PEA in your body it can affect you in some undesired ways. Scientists belive that amounts higher than 5 mg PEA is suspected to give migraine, they also belive that high levels can cause paranoia. A reduction in brain levels of phenyletylamine is thought to be one factor in causing depression. When phenylalanine (percursor) is metabolited to PEA it exerts antidepressant activity. In a study some patients took 100-500 mg phenylalanine every day for two weeks and it completely eliminated those patients depression. Researchers have also tried to find a connection between PEA and bulimia, but we found no results of these studies.


On Valentines day many people receive a box of chocolate from the man or woman in their life. Is this only a gesture of love or do they know the secret of chocolate? Chocolate is one of several romantic foods that consist PEA, yes that is correct. But don´t think that you fall in love when you eat it. Small amounts of chocolate makes you feel happy but the molecule of love is often quickly broken down by our bodies, so that it doesn´t even reach the blood. If you eat pounds of chocolate you only get a headache, so please don´t run away to the chocolatebox and eat it up. Save the box for those times when you feel down and take a piece of chocolate. Other food with PEA present are strawberries and spicy food.


Related Links



The Brain's Pharmacy, Emotional state and diet


About Depression

The chemistry of Love


Stryer, L. Biochemistry 3:rd ed. W.H. Freeman Co. NY 1988

Mathews Christopher K. Et al, Biochemistry, The Benjamin/Cummings Publ. Co. Inc. USA 1990

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