Serotonin is a neurotransmitter; which basically means it is a chemical messenger of the nervous system.

serotonin synapseMost people have heard of serotonin, it is frequently discussed in various ads in the media since we have direct to consumer marketing for pharmaceuticals in the U.S. As such, most people think of serotonin as a chemical that influences mood, especially in the case of depression. And while this isn’t too far off the mark, it’s actually only a very small piece of what serotonin is responsible for in your body.

Serotonin is manufactured in the brain and in the intestinal tract, in fact about 80% of your serotonin is produced in the gut. One of the functions of serotonin is to influence smooth muscle contraction, remember that your large intestine is comprised almost primarily of smooth muscle. Your serotonin levels influence the function of your digestive process. Serotonin also influences your reproductive and sexual function. Higher levels of serotonin can decrease libido and inhibit orgasm, while lower levels do just the opposite. This is one reason that taking SSRI’s (Serotonin Reuptake Inhibitors) can decrease libido and also romantic love. They are designed to keep serotonin flowing through your body as long as possible, which in turn can help manage certain mood imbalances.

Research is demonstrating that serotonin also plays a key role in cell division, which influences things like bone metabolism and liver regeneration. There is a strong correlation between SSRI’s and osteoporosis, mostly due to the increased levels of serotonin which impact bone density.

serotonin neuronLow levels of serotonin correlate with depression and suicidal behavior; while high levels of serotonin have been correlated with aggression, antisocial behavior, and even schizophrenia.

It’s important to keep in mind that when discussing terms like “high” and “low” with relation to health issues, we are referring to extremes at either end of a spectrum and not just the fluctuations of increase or decrease based on daily activity. Serotonin enters and exits the system relatively quickly, it basically has a short lifespan. This is how SSRI’s work, they close the door on the receptors that would normally pick up the serotonin and remove it from the system. This means the Serotonin stays floating around your system a little longer and can have more influence. If depression or instability is due to low serotonin, taking an SSRI can help balance the playing field in the brain. This works really well, except there is no way to just target the serotonin in the brain, so in turn, the serotonin in the gut is affected as well, which is where the digestive and sexual issues come in.

Serotonin flows when we feel satisfied or valued. When we are a valued part of community, with positive social interactions, we tend to feel more balanced and at ease. Reflecting on past accomplishments with genuine appreciation can also contribute to serotonin balance.
I think of serotonin as the chemical of ‘liking’ whereas dopamine is the chemistry of ‘wanting’; obviously it’s much more intricate than that but it sets the stage for beginning to understand the differences. Serotonin levels are also dependent on activity and diet. So, how you think, how you eat, and how you move all help balance your biochemistry. High protein diets have a strong correlation with decreased serotonin whereas high carb diets can result in just the opposite. The answer: balance, diversity of diet, movement, and self-appreciation.