All positive emotions we may experience in our lives that are connected with sensations of wellbeing – such as bliss and love at first sight – induce, it is well known, visible changes in our appearance and behaviour.
These changes may manifest themselves through a pink colour rising to the cheeks, a swelling of the heart, glittering eyes as well as blooming skin, alight with happiness. Women are never more beautiful, never feel more alive than when being struck by love at first sight – their eyes shine and their skin radiates. Understanding the origin of the physiological mechanism able to light up both skin complexion and mood is of great importance in the field of cosmetics.
Effect of dopamine at skin level
Behind the feeling of euphoria, there is a pure chemical and biological explanation based on the role of dopamine, the socalled “molecule of happiness”. Dopamine is a neurotransmitter that ensures the communication between neurons, affecting brain processes that control movement and emotional response. It plays an important role in feelings of desire and pleasure and its release is accompanied by an immediate exhilarating effect. Dopamine is also involved in proper skin functioning and a healthy appearance as it supports an appropriate supply to the cells by increasing microcirculation through a noninflammatory mechanism (Shigetomi S., 1994) and improves recovery of the skin barrier (Fuziwara S., 2005). To reproduce the beautifying effect positive emotions generate, Laboratoires Sérobiologiques (LS) has developed Euphoryl ?-3, a natural complex of Sacha inchi oil and pink pepper essential oil (INCI name: Plukenetia volubilis seed oil (and) Schinus terebinthifolius seed extract) that is able to promote a healthy appearance and wellbeing of the skin by stimulating the release of dopamine. Native in Brazil, pink pepper (Schinus terebinthifolius Raddi) is an Anacardiaceae traditionally used by American Indians as an astringent, stimulant and invigorating agent. Sacha inchi (Plukenetia volubilis L.) is an Euphorbiaceae native to the high altitude rain forests of the Andean region of South America. Sacha inchi oil contains 93% omega fatty acids, of which 85% are PUFAs (48% omega-3, 37% omega-6), and 8% is MUFA (omega-9), and is notably one of the richest sources of vegetal omega-3. Omega-3 fatty acids are a part of the large family of lipids and belong to the category of mono-unsaturated fatty acids (PUFA). They are called “essential” fatty acids because the body does not synthesise them. Studies have highlighted the capability of omega-3 fatty acids to induce dopamine synthesis in damaged neurons (Bousquet M., 2008), an effect that correlates with the improvement of mood disorders by nutritional supplementation with omega-3 fatty acids (Parker G., 2006). The antidepressant effect is linked to the synthesis of dopamine following the ingestion of omega-3. Finally, on the skin, omega-3 fatty acids play a role in counteracting hypersensitivity, skin dryness and inflammation and in addition have antioxidant properties.
Efficacy tests – protocols and results
The capability of Euphoryl ?-3, referred to subsequently in this article as the ‘natural complex’, to enhance the dopamine release from neurons, leading to an improvement of skin microcirculation without an inflammatory effect and resulting in a consumer-perceivable improvement of skin feeling and appearance, has been highlighted in efficacy studies and clinical trials. The efficacy of the natural complex was confirmed:
• In vitro, on the release of dopamine from neuronal cells (PC12).
• In vitro, on the release of PGE2 (prostaglandins E2) by human keratinocytes (non-irritating potential).
• In vivo, by evaluating the wellbeing effect: measurement of cutaneous microcirculation and a subjective questionnaire.
Dopamine release from neuronal cells (in vitro test) The aim of the test is to evaluate the potential of the natural complex to stimulate the release of dopamine from neuronal cells (PC12). Alpha-melanocytestimulating hormone (?-MSH) was chosen as the reference substance because it has been demonstrated that ?-MSH stimulates the synthesis of dihydroxyphenylanaline (DOPA) which is a precursor of dopamine.1 (See Figs 1 and 2). Conclusion: the natural complex at 0.001% has signifycantly increased the level of released dopamine at 3 days of incubation without a distinct modification of cell viability.
Demonstration of non-irritating potential: measurement of the release of PGE2 (prostaglandins E2) by human keratinocytes (in vitro test) The non-irritating potential of the natural complex was evaluated on a primary culture of human keratinocytes. The free fatty acid, arachidonic acid, was chosen as the reference irritant because it is metabolised by epidermal cells into proinflammatory messengers such as PGE2 (prostaglandins E2).3 (See Figs 3 and 4). Conclusion: the cell viability (MTT) was not modified (data not shown). The natural complex at 0.0003% and up to 0.003% did not significantly enhance the level of pro-inflammatory messengers from treated human keratinocytes. These results confirm that the natural complex does not have an inflammatory effect on human keratinocytes. The solvent used has neither modified the cell viability (MTT) nor the PGE2 release (data not shown).
In vivo evaluation of wellbeing effect (clinical test) Based on the in vitro efficacy on dopamine release, the natural complex is expected to have an effect on skin microcirculation and appearance. The “wellbeing” effect of formulations with 2% of the natural complex was evaluated, compared to a placebo, in vivo on human volunteers. The immediate effect was evaluated by measurement of cutaneous microcirculation. The Laser Doppler method allows evaluation and quantification of the effect of cosmetic treatments on the cutaneous microcirculation.4,5 An increase in microcirculation is considered to correspond to a better condition of the skin, and to the improvement of skin colour and complexion. The subjective evaluation (questionnaire) was made immediately and after 7 days of treatment. (See Figs 5 to 8). Conclusion: the application of the natural complex at 2% in a lotion immediately increased the cutaneous microcirculation which can be clinically translated into the improvement of the skin functioning and aspect. This effect was perceived by the end users after 7 days of treatment with the natural complex at 2% in a hydrogel: the volunteers reported the sensation of hydration (76%), freshness (81%) and comfort (62%) more frequently compared to the placebo treatment. Thanks to its capacity to boost dopamine production, the natural complex immediately improved microcirculation without associated irritation, which can be translated into a complexion and wellbeing enhancing effect.
Based on a combination of natural ingredients which help generate positive emotions, Euphoryl ?-3 is a pure happiness concentrate that lights up the skin’s complexion and enhances skin feeling of comfort and wellbeing thanks to its ability to stimulate dopamine release in the cells. It aims at revealing the resplendent skin of a woman in love and is therefore ideal for the formulation of “happy cosmetic” ranges, and ranges aimed at improving natural skin health. It can further be used in applications where increased microcirculation is beneficial — applications such as slimming treatments and scalp massage treatments. Its rich content in omega-3 fatty acids supports nourishing claims – there is a growing trend of concepts such as “Beauty from Inside Out” or “Cosmetofood”. It is preservative free and is approved by ECOCERT for use in the composition of natural and organic cosmetics.
1 Hunt G., Donation P.D., Lunec J., Todd C., Kyne S., Hody A.J. Cultured human melanocytes respond to MSH peptides and ACTH. Pigment Cell Res, 7: 217-221, 1994. 2 Galvani P., Colleoni M., Origgi M., Santagostino A. Mitochondrial toxicity of iron and the protective role of ferritin on dopaminergic PC12 cell line. Toxicology in Vitro, 9: 365-368, 1995. 3 De Leo V.A. Horlick H., Hanson D., Eisinger M., Herber L.C. Ultraviolet radiation induces changes in membrane metabolism of human keratinocytes in culture. J. Invest. Dermatol., 323-326, 1984. 4 Saumet J.L., Dittmar A., Leftheriotis G. Non- invasive measurement of skin blood flow: comparison between plethysmography, laserdoppler flowmeter and heat thermal clearance method. International Journal of Microcirculation, 5: 73-83, 1986. 5 Agache P.G., Dupond A.S. Recent advances in non-invasive assessment of human skin blood flow. Acta Dermato Venereologica, 185, 47-51, 1994. 6 Helen E. Fisher, Arthur Aron and Lucy L. Brown. Romantic love: a mammalian brain system for mate choice. Phil. Trans. R. Soc. B, 361, 2173–2186, 2006. 7 Shigetomi S., Fukuchi S. Recent aspect of the role of peripheral dopamine and its receptors in the pathogenesis of hypertension. Fukushima J Med Sci n° 40. 69-83, 1994. 8 Fuziwara S., Suzuki A., Inoue K., Denda M. Dopamine D2-Like Receptor Agonists Accelerate Barrier Repair and Inhibit the Epidermal Hyperplasia Induced by Barrier Disruption. J Invest Dermatol n° 125. 783-789, 2005. 9 Bousquet M., Saint Pierre M., Julien C., Salem N., Cicchetti F., Calon F. Beneficial effects of dietary omega-3 polyunsaturated fatty acid on toxin-induced neuronal degeneration in an animal model of Parkinson’s disease. FASEB Journal, n° 22. 1213-1225, 2008. 10 Parker G., Gibson N.A., Brotchie H., Heruc G., Rees A.M., Hadzi Pavlovic D. Omega-3 fatty acids and mood disorders. Am J. Psychiatry, n° 163. 969-978, 2006.