What’s the Difference Between Wellbutrin SR and Wellbutrin XL?

By Andrew Yocum, MD
Medically reviewed checkmarkMedically reviewed
March 2, 2022

We all feel sad, lonely, or down sometimes.

But depression is more than that—it’s a serious condition that can make normal life feel like a struggle, with everyday tasks like going to work or simply getting out of bed feeling more challenging.

As many as 280 million people worldwide suffer from depression, and it can impact relationships, work, and physical health.

There are many treatment options available to help cope with your symptoms—therapy, lifestyle changes, and antidepressant medication.

Wellbutrin (bupropion) is one of the most well-known antidepressant medications.

In addition to its original formulation, it also comes in “SR” and “XL” versions, standing for sustained release and extended release.

In this article, I’ll tell you about the difference between these two types of Wellbutrin, and what both are used to treat.

I’ll talk about their side effects, the difference in cost between the two types of Wellbutrin, and how bupropion is different from other antidepressants called selective serotonin reuptake inhibitors, or SSRIs.

I’ll also tell you when you should talk to a doctor about your depression symptoms.

What are Wellbutrin SR and Wellbutrin XL Used to Treat?

Wellbutrin SR and Wellbutrin XL are prescription antidepressant medications used to treat conditions like major depressive disorder and seasonal affective disorder. 

Major depressive disorder (MDD) is a serious mood disorder that most commonly affects young adults between the ages of 18-25.

People diagnosed with MDD usually feel sadness and loss of interest in activities and beloved hobbies.

They may also experience fatigue, difficulty concentrating, or feelings of worthlessness.

Over an extended period of time, these symptoms can make normal daily tasks seem like a great challenge. 

Seasonal affective disorder (SAD) is a form of major depression that occurs seasonally, usually during the fall and winter months.

While some people may shrug it off as the “winter blues,” SAD is a serious condition. It has been linked to a biochemical imbalance in the brain that is triggered by shorter daylight hours during winter.

Approximately 5% of adults in the U.S. experience SAD, and it can impact their lives for 40% of the year.

In some cases, Wellbutrin SR and Wellbutrin XL may be prescribed off-label for posttraumatic stress disorder (PTSD), anxiety, attention deficit hyperactivity disorder (ADHD), and social phobia.

“Off-label” means that the Federal Drug Administration (FDA) has not approved the medication for that particular condition.

However, a doctor may provide justification for why the medication will help manage their patient’s symptoms.

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What is the Main Difference Between Wellbutrin SR and Wellbutrin XL

Wellbutrin is a brand name for a medication called bupropion, and comes in three formulations: Wellbutrin, Wellbutrin SR, and Wellbutrin XL.

All of these medications contain the same active ingredient, bupropion hydrochloride.

The main difference between Wellbutrin SR and Wellbutrin XL is how the medication is released when ingested, and how often patients take it.

Wellbutrin SR stands for Wellbutrin sustained release.

The medication is released in the body for up to 12 hours.

Wellbutrin SR comes in 100 mg, 150 mg, and 200 mg tablets.

It is usually taken twice per day, compared to three daily doses for “regular” Wellbutrin.

Your doctor may recommend a single daily dose of Wellbutrin SR, but two doses is the most common.

Wellbutrin XL stands for Wellbutrin extended release.

This formulation releases medication over an even longer period of time—up to 24 hours.

Wellbutrin XL is available in tablets of 150 mg and 300 mg, and is usually taken once a day. 

How sustained-release tablets work

Sustained-release tablets lengthen the amount of time that a medication takes to release from a tablet, capsule, or pill, so you experience the benefits for a longer period of time—or the benefits of the pill can be spread more evenly throughout the day.

There is sometimes a coating on the pill, or another technology used, to delay the release and absorption of the medication by the body.

A sustained-release tablet also means that you may not have to take as many doses as you would with an immediate-release tablet.

It can be difficult to remember to take a pill multiple times each day, spacing out the doses perfectly.

Fewer doses are easier to keep track of, and can be more affordable too. 

Some research shows that the risk of seizures is lower in sustained-release formulations of Wellbutrin compared to immediate release Wellbutrin.

The study also noted that Wellbutrin SR was associated with less sexual dysfunction, sexual arousal disorder, and sexual desire disorder relative to other SSRI medications.

How extended-release tablets work

Extended-release tablets are similar to sustained-release tablets; in some medications, the terms are used interchangeably.

In the case of Wellbutrin XL, the extended-release tablets release medication at an ever slower rate than sustained release tablets, Wellbutrin SR. 

Depending on your body’s tolerance for Wellbutrin, an extended-release formulation may work better for you.

Slowing down the medication’s release within the body may lessen potential side effects.

Shared Side Effects

If you start taking Wellbutrin SR or Wellbutrin XL, you may experience one or a few of these possible side effects during the first few weeks:

Over time, these side effects should subside.

If they are severe, continue for weeks, or worsen over time, tell your doctor.

They may need to adjust your dosage, switch you to a new medication, or provide recommendations for how to alleviate the side effects you’re experiencing.

There are also rare, but serious side effects you should be aware of. If you experience any of the following symptoms, contact your doctor immediately:

  • Hallucinations
  • Seizures
  • Anxiety
  • Skin rash
  • Sweating
  • Tinnitus
  • Tremor
  • Muscle aches
  • Heart palpitations
  • Thoughts of suicide 
  • Changes in vision

Cost Difference Between Wellbutrin SR and Wellbutrin XL

The cost difference between Wellbutrin SR and Wellbutrin XL is negligible.

If you have health insurance, check to see if antidepressant drugs are covered.

Each insurance company and policy will have different coverage benefits.

Most Medicare plans cover antidepressants. Medicaid may also offer coverage.

If you are paying out of pocket or are seeking a lower co-pay, there are generic versions of both Wellbutrin SR and Wellbutrin XL available.

You can even get your Wellbutrin prescription online.

Wellbutrin vs. SSRIs

Some of the most commonly-prescribed antidepressants are selective serotonin reuptake inhibitors (SSRIs).

They increase levels of a neurotransmitter called serotonin in the brain. These include citalopram (Celexa), fluoxetine (Prozac), escitalopram (Lexapro), sertraline (Zoloft), and others.

Wellbutrin is not an SSRI. It is a norepinephrine-dopamine reuptake inhibitor, or NDRI.

Instead of increasing serotonin levels in the brain, Wellbutrin targets dopamine and norepinephrine, other neurotransmitters.

NDRIs are sometimes referred to as atypical antidepressants because they target different chemicals in the brain than other antidepressant classes.

Serotonin, dopamine, and norepinephrine are all neurotransmitters in the brain that play a key role in our mood.

Neurotransmitters are messenger molecules—they carry messages to and from the nerves, brain, and other cells.

Serotonin is thought to regulate anxiety, happiness, and mood.

Low levels of serotonin have been reported in patients with mood disorders.

Under normal circumstances, serotonin conveys its message and is then reabsorbed back into the body to be recycled.

When someone takes an SSRI, the medication works against this “reuptake” process, increasing the body’s level of serotonin and giving it more opportunities to communicate. 

Dopamine plays a role in how we experience pleasure, and affects motivation and perception of reality.

Norepinephrine plays a role in the body’s stress response, and helps regulate sleep, alertness, and blood pressure.

Like serotonin, when their message is delivered, these molecules are usually reabsorbed into the body.

NDRIs prevent the reabsorption of dopamine and norepinephrine to leave a larger supply readily available in the brain. 

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When to See a Doctor for Depression

While it’s normal to feel sad or lonely from time to time, these feelings should not persist for an extended period of time.

They should also not interfere with your daily activities and overall quality of life.

If you are experiencing symptoms of depression, do not feel ashamed or scared to reach out for help.

Here are a few signs of depression:

  • Loss of interest in activities you used to enjoy
  • Feeling hopeless or empty
  • Forgetting things, difficulty concentrating, or indecisiveness
  • Sleeping too much or too little
  • Unintentionally gaining or losing weight
  • Obsessive thoughts about death
  • Suicidal thoughts

If you are experiencing the symptoms above, there is medical help for you.

Talk to your doctor or another healthcare professional. 

How K Health Can Help

Think you might need a prescription for Wellbutrin (bupropion)?

K Health has clinicians standing by 24/7 to evaluate your symptoms and determine if Wellbutrin 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

Which is better, Wellbutrin SR or XL?
Both formulations are effective at relieving symptoms of depression. Wellbutrin XL is taken less often than Wellbutrin SR. Neither is “better,” but one might be better for your lifestyle or symptoms. In the end, it all boils down to your personal preference and your doctor’s recommendation. Some people may prefer Wellbutrin XL because they only need to take one pill a day.
Is Wellbutrin SR better than XL for weight loss?
Both Wellbutrin SR and Wellbutrin XL may cause weight loss or weight gain. Weight loss is more common.
Can you switch from Wellbutrin SR to XL?
Yes, but only under your doctor's supervision. If you decide that you would prefer Wellbutrin XL for the convenience of a single daily dose, talk to your doctor. If they find that Wellbutrin XL is a good fit for you, they will create a plan to help you properly transition from Wellbutrin SR to Wellbutrin XL. Never switch medications without clearance from your doctor. Doing so could lead to serious side effects.
How many hours does Wellbutrin SR last?
Wellbutrin SR releases medication for up to 12 hours.

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).