Medical Review by Jennie Stanford, MD, FAAFP, DABOM
Summary:
- Prozac® (fluoxetine) is an FDA-approved SSRI used to treat depression, some anxiety disorders, and other mental health conditions.
- Common side effects of Prozac® include nausea, insomnia, dry mouth, headaches, and weight changes.
- Short-term use of Prozac® may lead to weight loss due to appetite suppression, while long-term use can contribute to weight gain as mood stabilization restores appetite.
- Factors like your metabolism, genetics, and diet can all influence your individual response to Prozac®.
- A balanced diet and regular exercise can help counteract potential weight gain. Following a Mediterranean-style diet and staying active may improve your mood and support your overall well-being while taking Prozac®.
Prozac® is a branded form of fluoxetine, which belongs to a class of medications called selective serotonin reuptake inhibitors (SSRIs). It is often used to treat depression and other mental health conditions—but if you’ve never taken it before, you might be wondering whether it could affect your life in other ways as well.
Research suggests that there may be a link between antidepressants and weight gain—so will taking Prozac® make you gain weight? Lemonaid Health is here to help you understand what the science says so you can work with your healthcare provider to make an informed decision about whether this medication is right for you.
Prozac®: its uses & potential side effects
Fluoxetine has been shown to be effective at treating depression, and is generally considered safe to use. But like any medication, it comes with a risk of certain side effects. Some of the most common side effects in adults who take fluoxetine include:
- Insomnia
- Nausea
- Diarrhea
- Anorexia
- Dry mouth
- Headache
- Drowsiness
- Anxiety
- Nervousness
- Yawning
- Bruising
- Seizures
- Hyperhidrosis (excessive sweating unrelated to heat or exercise)
- Mania
- Weight gain/loss
- Sexual problems (difficulty achieving an orgasm in women or taking longer to ejaculate in men)
- Muscle weakness
- Tremors
- Pharyngitis (sore throat)
Fluoxetine can also rarely cause bleeding, and suicidal ideation or behavior (especially in younger people). If you or anyone you know are experiencing these symptoms, contact your healthcare provider immediately or go to your nearest emergency room.
You can learn more about what to expect when starting Prozac® here.
How Prozac® may affect your weight
You might have noticed that weight loss and weight gain are both listed above as potential side effects of Prozac®. That’s because Prozac® can affect your weight differently depending on how long it’s been since you started taking it.
People taking Prozac® for less than 12 weeks tend to lose some weight. This may be because certain side effects of the medication, such as dizziness and nausea, can also lead to an initial reduction in appetite.
While the exact reasons are unclear, Prozac® may also have an influence on leptin—a hormone from fat cells that helps regulate appetite and energy balance. Fluoxetine was shown to enhance leptin sensitivity in some studies on mice, which caused them to gain less weight than a control group.
However, Prozac® has been associated with minor weight gain during treatment of six months or more. This may be due to the fact that many people with depression experience a decrease in appetite as part of their symptoms. So when these people start taking Prozac, its mood-balancing effect may also bring back their appetite, leading to weight gain as an outcome.
Individual weight changes while taking Prozac®
Not everyone experiences the same weight changes while taking Prozac®. Genetics, metabolism, and preexisting health conditions can all contribute to how your body responds to this medication. Because individual responses to Prozac® can vary, it’s important to work closely with a healthcare provider while taking this medication so they can monitor the way your body is responding to it and make changes to your prescription if necessary.
Diet & lifestyle factors
Your diet and lifestyle can also play a role in whether SSRI use will lead to weight gain. Research shows that certain unhealthy behaviors can all make weight gain more likely for people taking SSRIs:
- Eating a Western diet (pre-packaged foods, refined grains, processed meat, high-sugar sweets, fried foods and high-fructose products)
- A sedentary lifestyle (involving little to no physical movement or exercise)
- Smoking
How to manage weight while taking Prozac®
Avoiding these activities by making healthier eating choices, getting adequate physical exercise, and avoiding smoking can all help reduce the amount of weight you are likely to gain while taking SSRIs like Prozac®. Here are some strategies:
Mediterranean-type diets have been shown to help with weight loss, but that’s not all. They also have a small-to-moderate mood-boosting effect. This type of diet focuses on eating plant foods and cereals, with olive oil as the main fat source. It also includes moderate amounts of dairy, low-to-moderate amounts of fish and poultry, and low amounts of red meat.
Exercise can also help with weight loss, especially if you get at least 150 minutes of moderate-to-intense aerobic exercise each week. Additionally, exercise increases feel-good chemicals like endorphins and serotonin, and lowers hormones associated with stress. This can make exercise a valuable ally when taking SSRIs like Prozac®, since it has potential benefits for both your body and mind.
Consulting your healthcare provider about Prozac®
Prozac® is a prescription medication, which means you’ll need to consult a healthcare provider before you can take it. When you do, you should talk to them about any mental health conditions for which you are seeking medication, as well as the specific symptoms you are experiencing. You will also need to talk to them about your personal and family medical history, including any medications you are currently taking.
If Prozac® does not seem right for you, your healthcare provider may recommend a different treatment. This could include an alternative depression medication, such as:
Each of these medications has its own benefits and potential side effects. Your healthcare provider will help you find the treatment that is most appropriate for your unique needs.
Learn more about Prozac® & your life with Lemonaid Health
Taking medication to manage your mental health can require some adjustments, and weight gain is one possible side effect of SSRIs like Prozac®. However, giving yourself time to adjust to Prozac® and making small, healthy changes to your diet and lifestyle can help minimize these effects while enhancing the medication’s benefits.
Lemonaid Health can help you create a personalized treatment plan for depression. Our team of US-based healthcare providers can provide expert advice about Prozac® and other medications, and may also be able to prescribe medication to you if clinically indicated for your case. Get started with us to find the support and resources you need.
Prozac® is a registered trademark of Eli Lilly and Company. Lexapro® is a registered trademark of H. Lundbeck A/S. Zoloft® is a registered trademark of Viatris Specialty LLC, a Viatris Company. Wellbutrin® is a registered trademark of GlaxoSmithKline LLC.
