Serotonin 101

By: Olivia Morrison

You know that sense of euphoria that zooms throughout your entire body the moment you’ve just finished a run? Or, do you remember the last time you got that   explosive yet fleeting feeling in your mouth right after eating a flavorful, wholesome, and nutrient-dense meal? Do you recall how you felt when you woke up too early that one morning and caught a glimpse of the red-hued sunrise burning over the Blue Ridge Mountains? These experiences which drastically enhance your mood are instances when your actions exponentially increase your serotonin levels (Bamalan, 2020).

 Serotonin is an integral neurotransmitter which helps regulate one’s “mood, memory, behaviours, perception, aggression, appetite, sexuality and attention” (Berger, 2009). An increase in serotonin is directly correlated to being in a more positive mood. A positive mood is an undeniable staple to happiness as an “important predictor of health and longevity” (Young, 2007). Serotonin’s powers go beyond just regulating mood, however; not only is the neurotransmitter an imperative regulator of all brain function, but it also helps regulate many other organ systems. Serotonin modulates “energy balance and food intake, GI and endocrine function, and cardiovascular and pulmonary physiology” (Berger, 2009). Bacteria in the gut “makes up about 95% of the body’s supply of serotonin” (Carpenter, 2012). Serotonin can also modulate “sleep, control of appetite and temperature” (Jenkins, 2016). 

The body’s synthesis of serotonin, however, is only possible through the help of tryptophan, an essential amino acid for brain function known as the precursor to serotonin (Jenkins, 2016). If tryptophan is not yet accessible to the “central nervous system through the blood brain barrier,” serotonin levels will be considerably low (Lindseth, 2014). In order to increase serotonin, one must also increase the amount of tryptophan in the body, which will then catalyze the serotonergic process. Tryptophan can be found in many protein based foods such as “meats, dairy, fruits and seeds.” It has also been found that “high-glycaemic index and glycaemic load meals” increase the availability of tryptophan in the body (Jenkins, 2016). While it is important to view food as fuel for your body, it is also easy to forget that food has a biological and cellular ability to improve your mood. Studies have shown how consuming large levels of tryptophan leads to an enhanced mood, while “lowering dietary tryptophan levels causes a lowering of brain serotonin levels” (Jenkins, 2016).  

One of the other main ways to improve serotonin levels is through exercise. Exercise increases “brain serotonin function in the human brain” and accelerates “serotonin synthesis” (Young, 2007). The most consistent increase in serotonin is seen when “regular exercisers undertake aerobic exercise at a level with which they are familiar” (Young, 2007.) Frequent exercise is also recommended as studies have shown doing something as simple as just running or swimming for at least 30 minutes daily increases “serotonin synthesis and metabolism in the cerebral cortex” (Heijnen, 2016). While “muscle activity requires the use of branched-chain amino acids,” aerobic exercise “reduces the amount of competitive amino acids through muscle uptake” (Heijnen, 2016). As a result, aerobic exercise, like running, improves “tryptophan’s chances of crossing the blood–brain barrier,” and thus can increase the amount of serotonin in the brain. (Heijnen, 2016). Lastly, it was also found that “exposure to bright light is a second possible approach to increasing serotonin” (Young, 2007). 

Overall, I advise you all to make efforts towards eating the right foods, exercising consistently, and getting some extra light exposure, which all collectively help to increase your serotonin levels and make you the happiest version of yourself. 

Reference List:

Bamalan, Omar A. “Physiology, Serotonin.” StatPearls [Internet]., U.S. National Library of Medicine, 3 Oct. 2020,

Berger, Miles, et al. “The Expanded Biology of Serotonin.” Annual Review of Medicine, U.S. National Library of Medicine, 2009,

Carpenter, Dr. Siri. “That Gut Feeling.” Monitor on Psychology, American Psychological Association, Sept. 2012,

Heijnen, Saskia, et al. “Neuromodulation of Aerobic Exercise—A Review.” Frontiers in Psychology, vol. 6, 2016, doi:10.3389/fpsyg.2015.01890. 

Jenkins, Trisha, et al. “Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis.” Nutrients, vol. 8, no. 1, 2016, p. 56., doi:10.3390/nu8010056. 

Lindseth, Glenda, et al. “The Effects of Dietary Tryptophan on Affective Disorders.” Archives of Psychiatric Nursing, W.B. Saunders, 9 Dec. 2014,

Parker, G., and H. Brotchie. “Mood Effects of the Amino Acids Tryptophan and Tyrosine.” Acta Psychiatrica Scandinavica, vol. 124, no. 6, 2011, pp. 417–426., doi:10.1111/j.1600-0447.2011.01706.x. 

Young, Simon N. “How to Increase Serotonin in the Human Brain without Drugs.” Journal of Psychiatry & Neuroscience : JPN, Canadian Medical Association, Nov. 2007,

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