How Long Does It Take for Prozac to Work?

Share This Post

What is Prozac | How does Prozac work | How long does it take to work | Side Effects | Treatment Options

Prozac is one of the most well-known and popular antidepressants on the market and is the preferred prescription drug treatment for millions of Americans suffering from common mental health conditions like depression and anxiety.

If you’re wondering how long it takes for Prozac to work, you’re not alone.

What is Prozac?

Prozac is a brand name prescription drug that is also sold under the generic name fluoxetine.

Prozac was the first medication in a class of drugs known as selective serotonin reuptake inhibitors (SSRIs) to be approved for use by the U.S. Food and Drug Administration (FDA).

how long does it take prozac to work image

Commonly used for the treatment of depression, anxiety, and other mental health disorders, SSRIs are among the most popular medications in the United States. Other SSRIs include sertraline (Zoloft), citalopram (Celexa), and paroxetine (Paxil).

Prozac was first approved to treat clinical depression in 1986, but since then, it has been approved for the treatment of many other mental health conditions, including major depressive disorder (MDD), a type of anxiety disorder known as panic disorder, obsessive compulsive disorder (OCD), bipolar disorder, bulimia nervosa, and premenstrual dysphoric disorder (PMDD). 

How does Prozac work?

Prozac is an antidepressant that is classified as a selective serotonin reuptake inhibitor (SSRI). SSRIs are thought to treat depression by reducing the ability of neurons in the brain to absorb serotonin, which is a type of neurotransmitter.

Serotonin acts as a type of chemical messenger in the brain, sending messages back and forth between the brain cells.  

When Prozac blocks the absorption of serotonin, it increases the amount of communication between the brain cells, which is thought to help improve and stabilize mood.

The drug is also known to active neurons in the portion of the brain that helps to form memories, known as the hippocampus. 

When taking Prozac, patients can experience physical and mental changes that include a lifted mood, increased energy levels, improvement to sleep and appetite patterns, and regained interest in activities that they once enjoyed.

How long does it take for Prozac to work?

SSRIs like Prozac take time to adjust the levels of serotonin in the brain and reduce symptoms of depression. While many patients hope to experience relief from their symptoms immediately, Prozac is a long term antidepressant that needs time to work. 

Prozac often begins to improve physical symptoms of depression like irregular sleep, appetite, or energy levels, first, sometimes in as little as one to two weeks.

If you are taking Prozac and notice improvements in your physical symptoms quickly, that’s a good sign that the medication is working as it should. 

Prozac takes longer to make the changes to your brain chemistry that are required to improve symptoms of depression and anxiety, so most people will need four to six weeks to experience the full effects of the medication.

Some mood symptoms, such as depressed mood and a lack of interest in activities you used to enjoy, may take as much as six weeks or more before improvement is noticed.

What are some common side effects of Prozac?

Prozac causes side effects that generally fall into two categories: common and rare/serious. 

Common side effects associated with Prozac include:

  • Headache
  • Dry Mouth
  • Nausea
  • Difficulty sleeping (insomnia)
  • Decreased libido
  • Diarrhea
  • Fatigue or tiredness
  • Drowsiness
  • Loss of appetite
  • Weight loss or weight gain
  • Worsening sweating
  • Feeling nervous
  • Restlessness
  • Sexual dysfunction, such as difficulty with orgasm or ejaculatory delay

Rare but serious side effects associated with Prozac include:

  • Low sodium blood levels, as indicated by:
    • Headache
    • Difficulty remembering
    • Weakness
    • Difficulty concentrating
    • Suicidal thoughts
  • Teeth grinding
  • Angle-closure glaucoma, as indicated by:
    • Swelling or redness in or around eye
    • Eye pain
    • Changes in vision
  • Serotonin syndrome, as evidenced by:    
    • Diarrhea
    • Severe muscular tightness
    • Fever
    • Confusion
    • Shivering
    • Seizures
    • Death
  • QT prolongation and ventricular arrhythmia including changes in the electrical activity of your heart

Treatment Options for Depression, Anxiety, and Other Mental Health Ailments

Image Product Features Price
$33/Week for 1st Month – Proven most effective

Medication + Therapy | Cerebral

Medication + Therapy | Cerebral
  • Evaluation, diagnosis, and prescription by a medical provider
  • Weekly video/phone sessions with a licensed therapist
  • Monthly medication delivery (if prescribed)
  • Chat securely with your therapist anytime
  • Regular progress tracking by provider & therapist
  • FSA / HSA eligible

Starting at $33/Week for 1st Month

Start Meds Today
$85/month – A completely digital experience

Online psychiatry evaluation + medication | Hims

Online psychiatry evaluation + medication | Hims
  • No searching for a psychiatrist
  • No waiting rooms
  • Licensed psychiatry providers
  • Evidence-backed medicine
  • Personalized treatment plan
  • Includes Medication cost

$85/month – Includes everything

Start Meds Today
$85/month – A completely digital experience

Online psychiatry evaluation + medication | Hers

Online psychiatry evaluation + medication | Hers
  • No searching for a psychiatrist
  • No waiting rooms
  • Licensed psychiatry providers
  • Evidence-backed medicine
  • Personalized treatment plan
  • Includes Medication cost

$85/month – Includes everything

Start Meds Today
$349/month – Most Effective Treatment Plan

Medication + Therapy | Brightside Health

Medication + Therapy | Brightside Health
  • FDA-approved medication
  • Evidence-based therapy
  • Always see and expert
  • All therapist hold a master's degree or higher
  • 85% of members feel better within 12 weeks
  • HSA/FSA eligible

$349/month – Coupon available. 

Start Meds Today


Prozac is a long-term antidepressant medication that needs time to reach its full effectiveness.

The medication begins to improve physical symptoms of depression and other mental health conditions in as little as one to two weeks after treatment begins, but mood symptoms such as feelings of sadness and loss of interest in activities that you used to enjoy may take significantly longer to resolve. 

You should always seek medical advice from a health professional before stopping antidepressants such as Prozac to avoid withdrawal symptoms.

Even a low dose of Prozac can lead to possible withdrawals. Prozac can be used while breastfeeding, even though it does pass into breast milk. 

Speak to your healthcare provider to determine whether Prozac is right for you.

Prozac may have negative interactions with certain drugs like monoamine oxidase inhibitors (MAOIs), and it can cause allergic reactions in some patients. Patients should allow four to six weeks for the medication to reach its full effectiveness.


Sesame Care

Find the best price for great doctors and specialists

  • Thousands of doctors and specialists
  • $13,000,000+ saved by patients
  • 95% patient satisfaction
  • 4.3 on TrustPilot

Popular Destinations

Recent Articles

Share On:

Subscribe To Our Newsletter

Get updates and learn from the best

More To Explore

Cerebral Review: Online Depression & Anxiety Treatment

Today, we’re deep diving with a Cerebral review to give you some insider info to help you narrow down your choices.

What are the signs of Depression?

In this article, we will discuss the signs and symptoms of depression as well as some treatment options for this condition.

Can You Use Gabapentin For Anxiety?

While Neurontin is the most common brand name for gabapentin, other forms (such as Horizant and Gralise) may be prescribed depending on the specific

Zoloft and Weight Loss: Everything You Need To Know

When it comes to Zoloft and weight loss, here’s everything you need to know.

What is Zoloft?

If you have been recently diagnosed with depression and are given Zoloft, you may want to know how the medication works, what common side

What is Venlafaxine HCL ER?

Common mental illnesses like major depressive disorder, generalized anxiety disorder, and panic disorder affect millions of Americans every year. While many different treatment options

Using Prozac With Alcohol: What Are the Risks?

Prozac has become perhaps the most well-known antidepressant in the United States since its approval for the treatment of depression in 1986. Since then,

How Long Does Clonazepam Stay in Your System?

Clonazepam is a popular medication that is most commonly associated with treatment for panic disorder, but the medication was originally developed as a treatment

What is Sertraline and What are the Side Effects?

Sertraline is the generic form of Zoloft, a medication that belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs). SSRIs like

Turn On, Tune In, and…. Heal Your Brain? Psychedelics Return as Potential Therapy for Mental Health Disorders

Before they fell out of favor over half a century ago, psychedelic drugs, like psilocybin and LSD, were studied for various psychiatric diseases such

How Long Does Alprazolam Stay in Your System?

Alprazolam is a fast-acting medication, but exactly how long alprazolam stays in your body varies tremendously based on the form of the medication taken,

Paxil vs Zoloft: Differences, Similarities and Which is Better

Paxil and Zoloft are both popular Food and Drug Administration (FDA)-approved antidepressants that are used to treat a wide range of mental health conditions.

A Supplement for Stress? The Science Behind Adaptogens

Stress is part of all our lives. Adaptogens are a group of herbal supplements studied throughout history as a way to improve the body’s

Does Buspirone Cause Weight Gain?

Many antidepressants can cause weight gain as a side effect. Buspirone may cause an altered appetite as a side effect, which can lead to

Duloxetine Withdrawal: Symptoms, Timeline, and Treatment

Duloxetine withdrawal is very common and well documented, affecting nearly half of all patients. Common withdrawal symptoms include dizziness, headaches, and nausea, and symptoms

Cymbalta vs. Prozac: Comparison Guide

Cymbalta and Prozac are commonly prescribed medications to treat mental health conditions such as major depressive disorder. The medications are similarly effective, although one

How Long Does Ativan Stay in Your System?

Ativan is a commonly prescribed prescription drug that is used by millions of Americans for anxiety, insomnia, and seizure disorders. It is the brand

Why is Mental Health Important?

As the saying goes, “There is no health without mental health,” but why is mental health so important? The reality is that although we

BuSpar: What is it? Uses, Costs, Benefits, and Doses

If you’re one of 40 million American adults suffering from an anxiety disorder or experiencing symptoms of anxiety, you might think that your battle

What are Long-Acting Injectable Antipsychotics? 

Long-acting injectable (LAI) antipsychotics have been shown to prevent psychosis relapse in patients with schizophrenia. To combat poor medication adherence, LAIs are a great