Antidepressants are effective for treating mental illness but can affect body weight. Although most antidepressants can cause weight gain, a few can cause weight loss.
Doctors often prescribe antidepressants to treat mental illnesses such as depression and anxiety.
Serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are second-generation antidepressants. They generally have fewer serious side effects and are better tolerated than first-generation antidepressants, such as B. tricyclic antidepressants (TCAs).
The SSRI fluoxetine (Prozac) and the SNRI duloxetine (Cymbalta) may cause loss of appetite and slight weight loss during the first few months of treatment. Bupropion (Wellbutrin), which blocks norepinephrine and dopamine, can also have this effect.
This article examines the link between antidepressants and weight change. It also describes other side effects and explains how to prevent weight loss.
Weight gain is a more common side effect of antidepressants than weight loss. A 2019 review of 27 studies found that people gain an average of 5% in weight after starting antidepressant therapy.
Various factors can cause a person to gain weight. Possible causes include:
- Some antidepressants increase appetite, so a person may consume more calories than their body needs.
- When a person is feeling depressed, they may become less active and burn fewer calories than they are consuming.
- Antidepressants can affect metabolism and cause the body to burn calories more slowly.
Some antidepressants can aid in weight loss by decreasing a person’s appetite, causing them to consume fewer calories than they burn. Additionally, mental health symptoms can affect a person’s eating habits and activity level, and treating the underlying condition can reduce or stop these effects.
Learn how many calories a person needs.
Some antidepressants do not cause weight gain or cause weight loss. These include:
- Bupropion: In a 2016 study, participants who did not smoke lost an average of 7.1 pounds (lb) after 2 years of treatment with bupropion compared to those taking fluoxetine. However, those who smoked gained an average of 2.2 pounds.
- Fluoxetine: A 2022 review found that for adults who are overweight or obese, taking 60 milligrams (mg) of fluoxetine daily resulted in an average weight loss of 2.7 kilograms (kg) — the equivalent of almost 6 pounds — during the first 6 months of life treatment can lead to. There is no weight loss effect for people taking low dosages for a long time.
- Duloxetine: An older study from 2006 found that people taking duloxetine for major depressive disorder lost weight in the short term but gained a small amount during longer-term treatment.
It’s common for side effects like weight loss to stabilize as the body adjusts to the drug.
A 2018 study found that taking antidepressants for at least 5 years was associated with weight gain.
The noradrenergic and specific serotonergic antidepressant (NaSSA) mirtazapine (Remeron) is most likely to cause weight gain. It is an atypical antidepressant. A 2016 study of 36 people taking mirtazapine found that after 2 years, these participants gained an average of 11.6 pounds.
The following SSRIs can cause weight gain:
Although it can cause weight loss in some people, fluoxetine (Prozac) can also cause weight gain in others. The effect of this drug on body weight can depend on the dose a person is given and the length of their treatment.
These older antidepressants can also cause weight gain:
Learn about antidepressants that can cause weight gain.
The Food and Drug Administration (FDA) doesn’t approve antidepressants for weight loss, so doctors don’t prescribe them for this use. However, doctors consider the potential effects of medication on weight when prescribing them.
Doctors may prescribe anti-obesity medications to help people with obesity lose weight. Options include:
Low to moderate weight people don’t need to lose weight, and excessive weight loss can be harmful. To maintain a healthy weight, a person should eat a nutritious, balanced diet.
This includes avoiding or limiting foods high in fat, salt, and sugar as they can raise low-density lipoprotein (LDL) cholesterol and blood sugar levels.
Instead, a person should try to eat meals and snacks that consist of:
- 5 servings of fruit and vegetables daily
- Whole-grain starches and carbohydrates at every meal, including oatmeal, potatoes, cereal, brown rice, whole-wheat pasta, and whole-wheat bread
- full fat milk
- Fish, eggs, poultry, meat or other protein sources
- 6-8 glasses of water per day, but not right before a meal as this can limit the feeling of being able to overeat
Protein powder milkshakes are a great way to increase calorie intake. People can also eat nuts, peanut butter toast, yogurt, or fruit between meals.
Antidepressants can cause side effects in some people. Type and severity can depend on factors such as age, gender, and other health conditions. The side effects may subside as the body adjusts to the drug.
The most common side effects include:
The following side effects are rare and require immediate medical attention:
If anyone experiences serious side effects, they should call 911 or go to the emergency room.
If other side effects worsen or cause concern, a person should make an appointment with a doctor.
People under the age of 25 are most at risk of suicidal thoughts when they first start taking antidepressants. It may be wise for a person to tell a friend or family member that they are taking antidepressants so that that loved one can stop by from time to time.
If antidepressants cause weight loss, it’s important to contact the prescribing doctor.
Weight gain is a common side effect of antidepressants, but some medications can cause weight loss instead. These drugs include bupropion, fluoxetine, and duloxetine.
Some antidepressants can affect appetite and lead to weight changes. A person may also change their activity level and eating habits due to mental illnesses such as anxiety or depression.
Weight changes often occur in the first few months of treatment, with a person’s weight stabilizing as their body adjusts.
Doctors don’t prescribe antidepressants specifically for weight loss, but they do consider a person’s health needs when choosing a drug.
Antidepressants can have a variety of side effects. If a person experiences any worrying or serious side effects, they should see a doctor.