Phenylethylamine (PEA) is a hormone that occurs naturally in the human brain. Small amounts are also found in chocolate; indeed PEA is responsible for chocolate’s noted anti-depressant qualities. Brain concentrations of PEA are elevated in people in love - it is said to account for the phenomenon of ‘love at first sight’.
PEA levels also increase following physical exercise, meaning sport has a positive effect on mood, as well as on physical health.
Deficiency is found in 60% of those suffering from depression, while PEA supplementation relieves symptoms of depression in 60% of patients.
Addiction to chocolate
Almost 14% of men and more than 25% of women experience compulsive cravings for chocolate which some experts attribute to the presence of three substances known for their psychotonic effects: theobromine, caffeine and phenylethylamine. A study has shown that our desire for chocolate may not only be due to its taste, smell and texture, but also to the feeling of well-being it gives us.
Chocolate is genuinely considered to have anti-depressant properties and to be able to simulate the effects of falling in love.
Historically, the Aztecs believed it had invigorating and aphrodisiac benefits though it must be said the chocolate drinks they prepared also contained an abundance of chilli, peppers and cloves.
Chocolate’s legendary aphrodisiac properties cross centuries as well as continents. In 1624, a French theologian condemned the consumption of chocolate in convents, claiming the beverage inflamed passionate feelings. In the 18th century, chocolate figured prominently among those foods considered to incite playful sexual activity. In 1702, in his Traité des Aliments, Louis Lémery wrote: “Its stimulating properties are likely to excite the passions of Venus”. Its anti-depressant effects were observed as early as the 17th century.
Somewhat disappointingly however, French researchers believe chocolate contains too little phenylethylamine or the other substances mentioned to cause such effects. There may actually be less phenylethylamine in chocolate than in goat’s cheese! Nevertheless, eating moderate amounts of chocolate can still have a mood-lifting effect.
Passion acts like a drug
Neurobiologists have shown that the phenomenon of ‘love at first sight’ results in the production of a large amount of phenylethylamine (PEA) in the brain. This natural neuro-hormone stimulates brain activity, provoking feelings of euphoria and ecstasy similar to those produced by certain drugs. Life seems wonderful, everyone looks beautiful and you feel brighter and happier than ever before.
PEA reduces appetite and incites heightened activity.
And its effects don’t stop there. It stimulates the release of dopamine, a neurotransmitter that influences several physical and psychological processes. Dopamine is closely linked to the limbic system, an area of the brain that controls emotions and vital functions such as hunger, thirst and sexuality.
Passionate feelings may therefore be the result of the brain becoming saturated with phenylethylamine and other natural stimulants which alter our state of mind and thus our reality.
Dr. Hector Sabelli, a scientist at the Center for Creative Development in Chicago, believes that, even with only indirect proof, “PEA may be the hormone of libido”.
Sabelli’s research shows that high levels of PEA may explain the increase in libido and sexual activity seen in the obsessive phase of manic depression while decreased levels reflect the low sex drive seen in the depressive phase.
Exercise’s anti-depressant effect may be due to phenylethylamine
It is widely acknowledged that physical activity has an anti-depressant effect. Indeed, some doctors recommend1
exercise as a treatment for mild depression, or as an adjunct to medication and/or psychotherapy for more severe depression.
Preliminary results of research carried out recently at Britain’s Nottingham Trent University1
, suggest that taking moderate exercise increases PEA levels in most people. The researchers believe this increase is responsible for the euphoric mood often referred to as ‘runner’s high’. In the study, twenty young men were asked to take moderate to intensive exercise, after which the scientists measured their urine concentrations of phenylacetic acid, a derivative of phenylethylamine. The results were telling. Phenylacetic acid concentrations increased by an average 77% following exercise, with significant variations between individuals, suggesting the young men were producing phenylethylamine.
Since depressed people tend to have low PEA levels, this could explain why exercise has a natural anti-depressant effect. The researchers hope their findings will encourage more doctors to prescribe physical activity for mild depression or as a complementary therapy to medication.
60% of people with depression have low PEA levels
It was established as much as twenty years ago that brain levels of PEA were markedly lower in people with depression compared with normal individuals.
A literature review suggests that PEA may be a neuromodulator of aminergic synapses and that it promotes energy, elevates mood, and favours aggression.
Phenylethylamine has a very short life, whereas levels of one of its metabolites, phenylacetic acid, are higher in body fluids. This is why excretion of phenylacetic acid (PAA) is thought to be a better measure of the modulating effects of phenylethylamine than the compound itself. It may even constitute a marker of depression.
Plasma and urine levels of PAA 3
have therefore been studied in depressed or bipolar subjects, as has the effect on mood of PEA’s precursor, phenylalanine. Average plasma concentrations of PEA were measured in 12 healthy volunteers and 23 people with major depression who were not taking any medication. Urine levels of PEA were measured in 48 healthy volunteers and 144 subjects with major depression. Results suggest that low plasma and urine levels of PEA may be markers of depression. Supplementation with phenylalanine was also shown to improve mood in 31 out of 40 depressed volunteers.
comparing the PAA urine levels of 39 patients suffering from major depression with those of 32 healthy subjects found the former were markedly lower than the latter.
A literature review of studies on urine excretion of phenylacetic acid involving 200 patients showed that around 60% of people with depression and schizophrenia have lower than normal PAA levels.
Administration of PEA or its precursor L-phenylalanine with a selective monoamine oxidase B inhibitor, has a mood-elevating effect in patients.
PEA relieves depression in 60% of cases
Like all major anti-depressants such as Prozac, PEA relieves depression in 60% of cases, but it produces far fewer side-effects.
Administration of phenylethylamine or one of its precursors, L-phenylalanine, combined with selegiline, relieves symptoms of depression and improves mood as rapidly as amphetamines but without leading to dependency.
are also apparent and supported in patients who do not respond to conventional treatment.
suffering major episodes of depression and who were responding to treatment with PEA (10-60mg/day, combined with 10mg of selegiline to prevent the destruction of PEA) were re-examined 20-50 weeks later. The anti-depressant effect had been maintained in 12 of the 14 patients with no apparent side-effects.
Several advantages over commonly-used therapies
When compared with more commonly-prescribed treatments, PEA has four main advantages:
- It acts very rapidly – in just hours or days instead of weeks. Such a fast-acting treatment could prove extremely valuable in reducing treatment duration and the length of time a person is unable to work, as well as in preventing suicide.
- It is virtually free from side-effects and toxicity. The selegiline administered alongside PEA is given at very low doses, similar to those used to delay the progress of Parkinson’s disease in older people.
- It is effective for various types of depression that do not respond well to standard anti-depressants. Equally, pharmacological treatments can work where phenylethylamine proves ineffective.
- Since PEA is correcting a neuro-hormone deficiency, it may be more effective with fewer, long-term side-effects, than a drug with a more complex, indirect action.
All of this does not mean that PEA will relieve all types of depression. However, the fact that it acts quickly and can be used for long periods without unwelcome consequences such as weight gain, sexual inhibition or other side-effects commonly found with conventional anti-depressants, means it can be given as a first-line treatment.
Since manic depression is a lifelong condition it is particularly important to emphasise PEA’s efficacy in bipolar patients.
1 Mutrie N “The relationship between physical activity and clinically defined depression”. In Biddle S, Fox K, Boutcher S, eds. Physical activity and psychological well-being. London: Routledge, 2000:46-62.
2 Szabo A, “Phenylethylamine, a possible link to antidepressant effects of exercises?” British Journal of Sports Medicine, 2001; 35: 342-3.
3 Sabelli HC et al. « Clinical studies on the phenylethylamine hypothasis of affective disorder : urine and blood phenylacetic and phenylalanine dietary supplements. »,J. Clin Psychiatry, 1986 Feb.; 47(2): 66-70.
4 Gonzales-Sastre F. et al. « Urinary phenylacetic acid excretion in depressive patients. » Acta Psychiatr Scand 1988 Aug; 78 (2): 208-10.
5 Sabelli H et al. « Phényletylamine modulation of affect : therapeutic and diagnostic implications ». J. Neuropsychiatry Clin. Neurosci. 1995;7: 6-14.
6 Sabelli H. et al «Sustained antidepressant effect of PEA replacement.» J. Neuropsychiatry Clin Neurosc, 1996 spr. 8 : 2, 168-71.