Why are you not losing weight on Topamax (topiramate)?

Key Points

• Topamax is not approved as a weight loss drug, but some doctors prescribe it off-label because weight loss is a side effect
• In studies, participants lost an average of 11 lbs on Topamax (topiramate)
• However, some people do not lose weight on Topamax for a variety of reasons
• Consult your doctor if Topamax does not work for you
• Weight loss is complex; a registered dietitian can help you with your weight loss goals

Your brain holds the surprising key to weight loss. That's why Topamax, a medication that calms neural activity for migraines and seizures, often triggers weight loss as a side effect.

But results on this drug are not universal. While most people find success with shedding pounds, a frustrated few watch the scale stand perfectly still, even though they're taking the very same pill.

If you're not seeing results on Topamax, understanding how this medication actually works in your body can help you discover more effective solutions.

What is Topamax?

Topamax is a medication that belongs to a class called anticonvulsants. It has FDA approval to treat seizures and to prevent migraines.

However, because of its calming effects on the brain, it may be prescribed “off-label” (for a purpose not officially authorized by the FDA) for weight loss, alcohol use disorder, bipolar disorder, post-traumatic stress disorder (PTSD), and even eating disorders like binge eating disorder and bulimia.

How does Topamax work?

Topamax works by regulating the flow of neurotransmitters, chemicals that act as messengers between your brain and the rest of your body. It reduces excessive electrical activity in specific brain pathways that are responsible for seizures or migraine headaches.

This calming effect on brain activity also influences pathways related to cravings, which is why researchers are studying Topamax for potential use in treating alcohol use disorder and other addictions.

This mechanism also appears to lower appetite, which explains why weight loss is a common side effect for many people taking this medication.

How much weight can you lose on Topamax?

Topamax is not approved for weight loss, but some doctors prescribe it off-label for individuals who are obese or have weight-related health concerns. It's also available in combination with phentermine in an FDA-approved weight loss medication called Qsymia.

The weight loss effect of Topamax occurs because it suppresses appetite and reduces food cravings. Research shows that people taking Topamax typically lose about 5-7% of their body weight within six months, averaging around 11 pounds.

Weight loss while taking Topamax may begin within the first month of treatment. For those using Qsymia, noticeable results might take about two months. This weight loss can continue even after a year.

What dose of Topamax do you need for weight loss?

Since Topamax is not FDA-approved for weight loss, there are no dosage recommendations for weight loss. A general rule of thumb is that higher doses of Topamax may lead to greater weight loss, but this comes with an increased risk of side effects.

Why are you not losing weight on Topamax?

Weight loss depends on many factors, and everyone’s body responds differently to medication. Overall, while many people lose weight on Topamax, some others do not. Here are some reasons why.

1. Maybe you need a different dose

If you've been taking Topamax for some time but haven't noticed any changes in your weight, it consider discussing your dosage with your doctor.

Topamax is available in various strengths, and finding the correct dose for your specific situation is important. Keep in mind that higher doses may lead to more pronounced side effects.

If you've only recently started Topamax, give it about one to two months to take effect before reevaluating your weight loss results.

2. You may need a different medication

Topamax has been around for a while. It first received FDA approval in the late nineties, and although it has demonstrated effectiveness for some people, newer medications specifically designed for weight management are now available.

GLP-1 agonists like Wegovy (semaglutide) and Zepbound (tirzepatide) are newer meds developed with weight loss in mind. If you're not seeing weight loss results with Topamax, it may be worth discussing these alternatives with your doctor, assuming your insurance covers them.

Registered dietitian, Kimberly Evans, RD, explains, “Topamax is most frequently used to treat seizures and migraines.  It is not a GLP-1 receptor agonist like semiglutide. While semaglutide mimics hormones that regulate hunger and satiety, Topamax influences the nervous system, resulting in a more indirect effect on cravings and appetite.”

Note: Please do not stop taking Topamax without consulting your doctor and under medical supervision.

3. Topamax side effects may work against weight loss

Evans, RD says, “Topamax is linked to cognitive side effects, including fatigue, which can make consistency with other lifestyle changes, such as increased movement or meal prep, more challenging.”

This brain fog is why Topamax has gained the informal nickname "dopamax" among some users. If you think this may be why you’re not losing weight on Topamax, talk to your doctor about potential alternatives.

4. Underlying insulin resistance challenges

Topamax appears to help certain parts of the body—muscles, fat cells, and heart tissue—respond better to insulin. This improvement in insulin sensitivity can make it easier for these cells to take in sugar from your bloodstream.

While this is helpful, it may not always be enough to keep the weight off long-term.

According to Evans, RD, “Topamax does not directly improve insulin sensitivity or counteract the metabolic adaptations that occur with weight loss. Instead, it influences neurotransmitter pathways [in the brain], which can initially reduce cravings and impulsive eating. However, over time, the brain adapts to these changes, leading to a diminished effect on appetite suppression and food cravings.”

To find the best approach for you, speak with your healthcare provider. Based on their assessment, they may recommend medication that better addresses insulin resistance.

5. Lifestyle changes may be needed

“All weight loss medications, including Topamax and semaglutide, work best in combination with a lifestyle approach,” says Evans, RD. “Nutrient balance, movement, sleep, and stress all play a significant role in weight regulation, as they affect hunger hormones and prevent metabolic adaptation.”

Eating more nutritious foods and exercising can enhance the positive effects of Topamax and improve your overall well-being. You can also receive a personalized weight loss nutrition plan tailored specifically to your needs.

6. Addressing binge eating 

Sometimes Topamax is prescribed for binge eating disorder to reduce appetite and binges. But when emotional eating triggers are not addressed, they can overpower the appetite-reducing effects of medication.

If you're on Topamax but still battle intense urges to binge on your comfort foods during times of stress, grief, or when trying to cope with other difficulties in your life, know that medication alone may not be enough. A mental health professional who understands these challenges may be able to provide the support you need.

As part of your binge eating disorder treatment team, a registered dietitian who specializes in binge eating disorder can help you develop a healthier relationship with food.

If you’re planning to take Topamax, it's helpful to be aware of the potential side effects you may experience.

Topamax side effects

Topamax (topiramate) side effects include:

• Weight loss
• Brain fog and cognitive function issues, including memory issues, trouble concentrating, and difficulty paying attention and focusing
• Nausea
• Dizziness
• Increased heart rate
• Suicidal behavior and thoughts
• Trouble with vision: harder to see things that are far away, or increased pressure in the eye (glaucoma)
• It is not safe for the unborn fetus in someone who is pregnant
• Trouble breathing
• Swelling in the face, mouth, and throat
• Allergic reactions on the skin, like itching, rash, or hives (pale red bumps on the skin)
• Hair loss (not a common side effect)
• Lower bone density

Note: This is not a complete list of side effects. For more information on Topamax side effects, refer to the product label and consult a healthcare provider.

Final thoughts: Not losing weight on Topamax

Topamax works by calming brain activity and reducing appetite, which is why it's sometimes prescribed for weight management alongside its FDA-approved uses for epilepsy and migraines.

But our bodies are wonderfully complex and uniquely our own. If Topamax isn't helping with your weight goals, there may be many reasons why. You may need a higher dose, a different drug, or there may be underlying health conditions that are interfering with your weight loss.

If you’re still binge eating on Topamax, consider reaching out for mental health counseling. Plus, a registered dietitian who specializes in treating binge eating disorder can provide valuable guidance.

Start losing weight. Find a registered dietitian near you, covered by insurance.

Frequently Asked Questions (FAQs)

1. Topamax vs. Qysmia: What’s better for weight loss?

Qysmia shows better weight loss results than Topamax (topiramate) alone.

Qysmia is an FDA-approved combination pill of topiramate and phentermine, specifically approved for long-term weight loss. It takes about two months to experience weight loss on this drug.

2. How much weight can you lose on Topamax?

In clinical studies, people lost an average of about 11 pounds (5-7% of their body weight).

3. How fast can I lose weight on Topamax?

Topamax can start working quite fast. Research shows that weight loss on Topamax may begin within four weeks of starting the medication.

4. Why am I gaining weight on Topamax?

Weight gain is not a common side effect of Topamax. The medication works by reducing appetite. If you’re experiencing weight gain on Topamax, please talk to your healthcare provider to explore potential reasons why or alternative medications.

5. Can a dietitian help me lose weight on Topamax?

Evans, RD says, “It is frustrating to put so much effort into something and not see the results you were hoping for. You may have tried multiple times to lose weight and had high hopes that Topamax would be different. Weight loss is complex, and it might be helpful to explore some possible reasons why Topamax has not delivered the results you were looking for.”

A registered dietitian can help you explore reasons why your weight loss has stalled on Topamax, including how satisfied you feel with the meals you are eating, any changes in your energy levels, sleep patterns, or stress levels.

Find a weight loss dietitian who accepts your insurance.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.