Effexor and Weight Gain

By Andrew Yocum, MD
Medically reviewed checkmarkMedically reviewed
May 3, 2022

When starting a new medication, it’s normal to feel anxious about how your body may react.

The prospect of experiencing side effects can be daunting, and depression and the medications used to treat it can affect your appetite and body weight in unwanted ways.

While side effects can range from annoying to scary, it’s also important to note that most of the time, the positive effects of the medication outweigh the negative. 

In this article, we’ll review a common side effect of antidepressants: weight gain, specifically in the context of Effexor.

We’ll review what Effexor is, the relationship between this medication and weight gain, and common side effects when taking it.

We’ll also go over precautions and when to see a doctor. 

What is Effexor?

Effexor (venlafaxine) is an antidepressant that is commonly prescribed to treat symptoms associated with depression and anxiety.

Effexor helps relieve symptoms that may occur with depression and anxiety, like sadness, hopelessness, guilt, and lack of interest in things that once brought you joy.

It can also be used to treat physical manifestations of anxiety, including nausea, jitters, or restlessness, amongst other things. 

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Effexor uses

Effexor is used to treat anxiety disorders, panic disorders, social phobia disorder, as well as major depressive disorder.

It can also be prescribed as a mood stabilizer, as well as used to treat post-traumatic stress disorder, bipolar disorder, and attention-deficit hyperactivity disorder. 

Other studies show that venlafaxine is effective in treating nerve pain, migraines, and tension headaches.

It has also been prescribed to treat hot flashes as a result of menopause or chemothrapy.

These are “off label” uses, meaning the FDA has not approved them for these diseases but prescribers can decide if it’s appropriate for individual patients.

How Effexor works

Antidepressants work by affecting the chemicals in the brain known as neurotransmitters.

These include the managing of available levels of serotonin, norepinephrine, and dopamine.

Effexor is part of a class of drugs known as SNRIs (serotonin-norepinephrine reuptake inhibitor), which regulate the amount of serotonin and norepinephrine molecules in the brain by blocking the reabsorption or reuptake of such chemicals.

This makes more of these chemicals available in the brain and results in mood regulation.

Effexor and Weight Gain

Many antidepressant and anxiety medications list weight gain as a potential side effect.

This is the case with Effexor as well, but not everyone experiences such side effects. 

What the research says

Studies show that newer antidepressant drugs may be associated with weight gain.

In one such study, venlafaxine was associated with significant weight gain, alongside citalopram (Celexa), escitalopram (Lexapro), sertraline (Zoloft), and paroxetine (Paxil).

Some studies and clinical studies show that patients treated with Effexor gain a significant amount of weight, while other studies show that weight gain from venlafaxine is small and potentially insignificant. 

While studies show that some antidepressants may cause weight gain, the effect of antidepressants on weight is still mixed and needs further examination. 

Common Side Effects of Effexor

Like many medications, there are a variety of side effects that may occur when taking Effexor.

These side effects are often mild, and a doctor will usually prescribe a low dose to start and build up slowly to a higher daily dose to avoid significant side effects.

Many of the side effects should go away within a few weeks. 

Common side effects include:

Depression and Weight Changes

There are a number of signs of depression.

A common one to look out for is appetite changes.

This may include a noticeable weight gain or loss.

This may occur in both clinically depressed, as well as “high functioning” depression

Those who are depressed may be less likely to make healthy eating choices, which may affect one’s weight more than a medication itself.

Depression also affects energy levels and your desire to do things that you once enjoyed.

This may affect one’s desire to exercise regularly, an important part of maintaining a healthy body weight. 

How to Take Effexor

Effexor is often taken daily with a starting dose of 37.5 mg per day, which is increased over time to 75 mg daily, a common dosage to treat depression, generalized anxiety, panic disorders, and social anxiety disorder.

Your doctor may adjust your dosage over time, but they do not usually recommend going over 225 mg per day. 

Effexor Precautions

Before starting Effexor, tell your doctor about all medications and supplements you take, as some can interact with the medication and cause serious side effects.

Especially in the beginning, it is best to avoid alcohol, as venlafaxine can make you drowsy. 

Before stopping Effexor, consult your doctor and they will help you wean off the medication.

Sudden and immediate stopping can cause withdrawal side effects like nausea, vomiting, headache, and irritability. It’s best to stop taking Effexor with the help of a psychiatrist. 

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When to See a Doctor

Speak with your doctor about what antidepressant medication is right for you.

If your side effects worsen or symptoms don’t begin to resolve in 6 weeks, you may want to try a different dose of medication. 

Contact a doctor immediately if you suspect signs of an overdose, which includes dizziness, flashes of hot and cold, dilated pupils, irregular heart rate, and seizures. 

With drugs that affect the serotonin levels in your brain, there is a risk of serotonin syndrome.

This is when your body has too much serotonin and requires immediate medical attention.

Symptoms include restlessness, insomnia, confusion, high blood pressure, sweating, diarrhea, headache, and goosebumps. 

If you experience serious side effects, including suicidal thoughts or worsening symptoms of depression, talk to someone immediately, such as calling a suicide crisis line like 988.

How K Health Can Help

Think you might need a prescription for Effexor (Venlafaxine)?

K Health has clinicians standing by 24/7 to evaluate your symptoms and determine if Effexor is right for you.

Get started with our free assessment, which will tell you in minutes if treatment could be a good fit. If yes, we’ll connect you right to a clinician who can prescribe medication and have it shipped right to your door.

Frequently Asked Questions

Will Effexor help me lose weight?
Side effects vary from patient to patient, but neither weight loss nor weight gain is guaranteed when taking antidepressants. Additionally, Effexor is not amongst the list of antidepressants that have been connected to weight loss, which include bupropion (Wellbutrin), fluoxetine (Prozac), and duloxetine (Cymbalta). The best way to lose weight is to make healthy lifestyle and eating choices, which can include managing caloric intake.
Has anyone gained weight on venlafaxine?
Weight gain is a possible side effect accompanied with taking venlafaxine, but side effects vary depending on the patient. The bottom line is that while some people may gain weight, there is no way to know whether you will experience such a side effect.
Is it hard to lose weight on venlafaxine?
While some patients in one study found it difficult to lose weight during and after taking venlafaxine, this is not a universal experience and will differ from patient to patient. If you’re having trouble losing weight on venlafaxine, seek the help of a registered dietitian.
Does Effexor affect appetite?
Decreased appetite is one of the possible and common side effects of Effexor. This may affect your weight, but will likely resolve as your body adjusts to the medication.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Andrew Yocum, MD

Dr Andrew Yocum is a board certified emergency physician. He graduated Summa Cum Laude from Kent State University with a Bachelor of Science in Molecular Biology before attending Northeast Ohio Medical University where he would earn his Medical Doctorate (MD).

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