Sunshine and Serotonin, and Skin: Is sunlight the key to happiness?

By Jasmine Riley

Warmer months always attract many people to outdoor attractions and activities. Whether it be hiking, swimming, or just enjoying a nice walk outside, the welcoming warmth of spring and summer beckons to the masses to enjoy the outdoors. This time of year also shows a decrease in reports of seasonal mood disorder symptoms, such as anxiety and depression. Several studies indicate that there can be seasonal variations in the expression of psychiatric phenomena, especially mood and anxiety symptoms. While the explanations for the relationships between seasonal changes and exacerbations of psychopathology remain unclear, there is enough evidence that an association between sunshine and serotonin is likely. So, is sunshine the key to happiness? 

To examine this possibility, we must first look at the processes involved with producing serotonin. Serotonin is a neurotransmitter that mediates satisfaction, happiness and optimism. Serotonin levels are reduced in depression, and most modern anti-depressant drugs, known as serotonin reuptake inhibitors (SSRIs), act by increasing the amount of serotonin available to brain cells. Could sun exposure also lead to more available serotonin in the body? Studies indicate it is a very great possibility. While there is more concrete evidence of serotonin mobilization due to visual stimulation via sunlight, another major medium for creating serotonin may lie within the biggest organ of our bodies: the skin. 

Numerous studies indicate that there are numerous relationships between the skin and serotonin production in the body. One major study conducted in 2002 lends its finding to this fact as well. In this experiment, investigators examined the effects of light exposure in the laboratory for three weeks on 42 subjects in comparison with 11 controls. All participants wore opaque goggles, which for those exposed to light were designed to block out ultraviolet-A radiation (i.e., to eliminate the retinal mediation of serotonin effects). Individuals exposed to light evidenced higher serum serotonin levels during this experiment than controls, which the authors proffered might be explained by a “cutaneous pathway.” This means that serotonin mobilization could take place via the skin. This would also explain the drastic differences in reported symptoms of mood disorders during warmer months. 

To close, for those who are looking to increase their feelings of happiness and satisfaction, or even those who experience symptoms of mood disorders, there is a high likelihood that some fun in the sun will have a great impact on your mood. Use this summer to add outdoor activities to your and see how your mood changes.

Enjoy some fun in the sun while staying safe from UV rays. For information on how you can practice safe summer fun, check out the following links:



Sansone RA, Sansone LA. Sunshine, serotonin, and skin: a partial explanation for seasonal patterns in psychopathology? Innov Clin Neurosci. 2013 Jul;10(7-8):20-4. PMID: 24062970; PMCID: PMC3779905.


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