Serotonin vs. dopamine: A guide to the two mood-regulating hormones and how they can affect your health

Nov 6, 2020, 4:12 PM

working out happy — When you accomplish a task, like working out, your body releases dopamine.

Serotonin helps you feel happier, calmer, and more focused — while dopamine makes you feel motivated, accomplished, and productive.
Serotonin and dopamine both play a role in regulating our digestion, by suppressing or increasing our appetite according to our body's needs.
A lack of serotonin, dopamine, or both neurotransmitters have been linked to certain mental health conditions like addiction and depression.
This article was medically reviewed by David A. Merrill, MD, PhD, psychiatrist and director of the Pacific Neuroscience Institute's Pacific Brain Health Center at Providence Saint John's Health Center in Santa Monica, California.
Visit Insider's Health Reference library for more advice.

Dopamine and serotonin are both neurotransmitters — chemical messengers that transmit signals between cells — which regulate bodily functions like mood, sleep, and digestion.

While dopamine and serotonin have similar effects on the body, they work a bit differently. Here's what you need to know about the similarities and differences between dopamine and serotonin.

Dopamine makes you motivated

Dopamine is stored in the brain and released into the bloodstream when you experience pleasurable sensations, like listening to music or eating something you enjoy.

The neurotransmitter plays a major role in your body's motivation and reward system, inciting positive mood, feelings of productivity, and heightening motivation. You've likely felt the effects of dopamine after accomplishing a difficult task or reaching a goal.

For example, if you buy a lottery ticket on a whim, you will not feel an immediate sense of reward. However, if you end up winning, you're likely to experience a rush of dopamine, reinforcing the likelihood you'll buy a lottery ticket again to experience the same thrill.

Because dopamine is related to the reward system and reinforces pleasurable experiences, it is thought to play a role in addiction and compulsive gambling, though researchers aren't yet sure of the exact link between dopamine and these behaviors.

Dopamine also affects memory, cognition, sleep, attention, and ability to learn. Insufficient levels of dopamine may be related to depression or Parkinson's disease.

Serotonin helps you feel good

Serotonin plays a role in how we process our emotions, which can affect how we feel. Serotonin is released into the bloodstream after exercising or being in sunlight. Proper levels of serotonin can make you feel happier, calmer, more focused, and less anxious.

Meanwhile, low levels of serotonin can have the opposite effect and negatively impact your mood. Low levels of serotonin have been linked to depression as well as sleep and appetite disturbances, Stover says.

Serotonin also regulates important bodily functions. For example, your gut, which houses 90% of the body's total serotonin, releases chemicals when you eat to stimulate your intestines and move food through your digestive system. Blood platelets also release serotonin when you get a cut or scrape to heal wounds.

Other bodily functions and processes serotonin helps regulate include:

Mood
Emotions
Your circadian rhythm, or sleep-wake cycle
Appetite
Metabolism
Concentration
Hormones

The relationship between serotonin and dopamine

Serotonin and dopamine do not function independently of one another. Instead, they work together to create complex patterns of behavior.

"When one neurotransmitter is altered, there is a change in the function or prevalence of the other substance," Stover says. "Increased levels of serotonin can lead to decreased dopamine activity and vice versa."

For example, serotonin inhibits impulsive behavior while dopamine enhances it. Because low levels of serotonin can cause an overproduction of dopamine, some researchers say this could lead to an increase in impulsive behavior.

Dopamine and serotonin also have opposite effects on your appetite. Low dopamine levels stimulate hunger while low serotonin levels suppress hunger. Therefore, the proper levels of both neurotransmitters are important for adequately receiving hunger cues and recognizing when you are full.

Serotonin, dopamine, and depression

Because both dopamine and serotonin affect mood, they are thought to play a role in mood disorders like depression. For example, researchers have observed decreased levels of serotonin in people with depression and other types of mental illness, like anxiety and attention deficit hyperactivity disorder (ADHD).

However, that doesn't mean low levels of serotonin cause depression, Stover says. Depression is a complex disorder caused by a combination of many different factors including family history, stressful life events, and trauma. Therefore, low levels of serotonin may be part of the picture, but probably won't fully explain why depression occurs.

"Because serotonin is responsible for sleep, mood, and digestion, we often see symptoms of depression that reflect that imbalance, such as sleeping too much or too little, having no appetite or overeating," Stover says.

While a low level of serotonin alone isn't a direct cause of depression, medication targeting the chemical can improve depressive symptoms. For example, selective serotonin reuptake inhibitors (SSRIs), a common type of antidepressant, increase serotonin in the brain. This improves communication between brain cells and can help lift your mood.

Low levels of dopamine can also cause some symptoms of depression, such as lack of motivation and loss of pleasure in activities that you once enjoyed.

Long-term or chronic stress can also lead to elevated cortisol levels — a hormone released as a stress response. High levels of cortisol reduce the production of both serotonin and dopamine and have been linked to depression, says Nicole Avena, PhD, an assistant professor of neuroscience at Mount Sinai Medical School and a visiting professor of health psychology at Princeton University.

"Targeting the dopamine system is one of the ways in which we can look at potential mechanisms and treatments for depressive behaviors," Avena says.

Insider's takeaway

Dopamine and serotonin are both neurotransmitters that are involved in many similar bodily functions, though they have key differences in how they affect behavior. Overall, dopamine and serotonin work together to help regulate mood, and low or elevated levels of either hormone may negatively impact your mental health.