Phentermine vs Qsymia – Is it better to take alone or Combine?

  • By: jacob foxx
  • Date: April 26, 2023
Phentermine vs Qsymia

Qsymia is a combination therapy drug consisting of phentermine and topiramate, which are used to suppress hunger and work similarly to phentermine.

While the additional drug in the Qsymia formulation may offer benefits, it also poses potential risks, resulting in a greater risk-to-benefit ratio.

Despite this, Qsymia may still be an option for individuals with no contraindications.

Although phentermine is generally the preferred diet pill, this article provides an extensive review of Qsymia and phentermine, including benefits, safety, user reviews, cost, and pros and cons of each medication.

With this information, users can make an informed decision regarding which medication is the best fit for their specific needs.

A Quick Overview of Qsymia and Phentermine

Phentermine and Qsymia are powerful appetite suppressants designed to promote weight loss when combined with dietary changes and exercise.

Qsymia is an FDA-approved medication available in four different doses that contain varying concentrations of phentermine and topiramate.

It is taken orally once a day, with or without food. Phentermine, on the other hand, is available in four different dosages: 8 mg, 15 mg, 30 mg, and 37.5 mg.

The lower dosages are recommended to be taken three times a day before breakfast, while the higher dosages should only be taken once before or after breakfast.

These medications are prescribed to individuals with an initial BMI of 30 kg/m2 or greater, or if they have an initial BMI of 26 kg/m2 and have co-morbid diseases like hypertension, diabetes, and abnormal lipid levels.

Phentermine and Qsymia safety

FDA approval

Phentermine and Qsymia are both FDA-approved medications for the treatment of obesity. While they both have the same purpose, they differ in terms of treatment duration.

Phentermine is intended for short-term use only, usually for a maximum of 12 weeks. On the other hand, Qsymia is approved for long-term use, for 6 to 12 months.

Both medications are classified as Schedule IV controlled substances, which means they have the potential for misuse.

Safety information

Qsymia, a medication used for weight loss, contains phentermine and shares the same safety concerns as other drugs that also contain this ingredient.

These drugs pose a significant risk to a fetus and are not recommended for women who are trying to conceive, have already conceived, or are breastfeeding.

Numerous studies have been conducted to assess the safety of these drugs in adults over 16 years of age, but not in younger age groups.

One important note when taking Qsymia is to avoid taking it late in the evening, as this may cause insomnia.

Contraindications to medications

Phentermine and Qsymia are two common prescription medications used for weight loss, but both come with a laundry list of possible interactions and contraindications.

Phentermine, for example, has 42 major, 126 moderate, and 2 minor drug interactions, and should be avoided in patients with 17 different diseases.

Qsymia, on the other hand, may react with 387 drugs, resulting in 145 major reactions, 239 moderate reactions, and 3 minor drug interactions, and is not suitable for patients with 26 different diseases.

Patients who have a history of drug abuse or are allergic to either medication should avoid them altogether.

Qsymia should also not be prescribed for patients who have taken monoamine oxidase inhibitors (MAOIs) within the past 14 days, as it may cause high blood pressure. Women using oral contraceptives should also be aware that Qsymia may decrease their efficacy. 

The side effects of phentermine

Discontinuing the use of phentermine can lead to a range of symptoms for users. Among the most commonly reported side effects are fatigue and depression.

However, this prescription medication can also cause a host of other issues, such as anxiety, dizziness, and gastrointestinal problems, including constipation and dry mouth.

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While these symptoms may be mild for some, in rare cases, more severe and potentially dangerous reactions can occur, such as heart valve defects and primary pulmonary hypertension. 

The side effects of Qsymia

Qsymia is known to cause various side effects that affect almost all body systems. Some commonly reported nervous system side effects include headaches and pins and needles sensations.

However, psychological symptoms such as anxiety, depression, and irritability also occur with this drug.

Metabolic disturbances, electrolyte imbalances, and a decrease in appetite are also reported. High serum creatine levels may pose a threat to the kidneys, while heart palpitations and high blood pressure affect the cardiovascular system.

Gastrointestinal issues like constipation and dry mouth may occur with the use of Qsymia. Moreover, genitourinary tract infections are quite prevalent among users of this drug.

Qsymia can even compromise the immune system and cause flu-like symptoms. Therefore, although Qsymia may aid in weight loss, it is essential to also take into account the potential harm it may cause to various body systems.

User reviews

Phentermine has attained a highly rated reputation, with an average rating of 8.7 out of 10 on, with 84% of positive reviews.

Users of phentermine have reported significant progress in their weight loss journey, along with an increase in energy levels.

However, some negative reviews have reported psychological symptoms like depression or phentermine plateaus. Qsymia, on the other hand, has an average rating of 7.8 out of 10 with 72% of positive reviews.

Although dry mouth, depression, tingling in hands and feet, hair fall, and rash are common side effects of both phentermine and Qsymia, their efficacy in weight loss has been highly praised by numerous users.

Qsymia and Phentermine Cost

Qsymia’s lowest dose comes at an average retail price of $233.85 for 30 capsules, and its highest dose costs around $248.04.

But for those who still want to try Qsymia, there is a paid home delivery scheme available via their website.

On the other hand, Phentermine, a similar weight loss medication, has low-cost generic forms available that cost only $36.5 for 30 tablets at the highest dose of 37.5 mg.

In terms of cost-effectiveness, Phentermine is more favorable compared to Qsymia.

Pros and Cons of Phentermine


  • FDA-approved for weight loss
  • Reduces appetite
  • May lead to rapid weight loss results
  • Can reinforce healthy habits and lifestyle changes
  • No stimulants like caffeine


  • Most insurance companies do not cover the cost of phentermine
  • Has a risk of abuse and dependence since it’s similar to amphetamines
  • Possible side effects range from mild to severe, including nausea and rapid heart rate
  • Should not be used long-term
  • Can cause metabolic damage if used daily in high doses

Pros and Cons of Qsymia


  • Only taken once a day
  • Combines two medications, phentermine, and topiramate, into one pill for convenience
  • Clinically proven to induce an average weight loss of 15 lbs after taking the medication for 3 months


  • May cause birth defects and increase the risk of cleft lip and palate
  • Topiramate may cause suicidal thoughts or actions
  • Requires dieting and exercise to reach its full potential and may cause some side effects, such as dizziness


Is phentermine as powerful as Qsymia?

Yes, phentermine can be effective in aiding weight loss, but it can also be addictive and tolerance may develop.

Qsymia, on the other hand, combines phentermine with another agent, topiramate, which has been shown to have even better efficacy in aiding weight loss.

It is important to note that Qsymia is a prescription-only medication and should be taken alongside a healthy diet and exercise regimen.

Can you combine Qsymia and phentermine?

Unfortunately, Qsymia and phentermine are the same thing. Qsymia is a brand name for a combination of phentermine and topiramate, while phentermine is the generic name for the same medication. Therefore, taking Qsymia and phentermine together would essentially be taking the same medication twice.

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Qsymia contains how many milligrams of phentermine?

Qsymia is a medication that contains a combination of phentermine and topiramate. Each capsule of Qsymia contains different amounts of phentermine and topiramate.

The amount of phentermine in Qsymia varies depending on the strength of the medication. The three available strengths of Qsymia are 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg.

Therefore, the amount of phentermine in Qsymia ranges from 3.75 mg to 15 mg, depending on the strength of the medication.

How quickly does Qsymia help you lose weight?

While results vary from person to person, most people taking Qsymia can expect to lose at least 5% of their body weight within 12 weeks. However, research has shown that some people lose significantly more weight than this, up to 10% or more of their starting weight.

Of course, it’s important to keep in mind that weight loss is never a one-size-fits-all journey, and results will depend on various factors, including your metabolism, lifestyle, and overall health.

Is Qsymia more effective than phentermine?

Based on our research, Qsymia is a combination of phentermine and topiramate ER, which helps to suppress appetite and promote weight loss. In comparison, phentermine is also used as an aid in weight loss but may be addictive and lead to tolerance over time.

While the efficacy of Qsymia is higher than that of phentermine, it’s essential to note that both are prescription-only and administered alongside a healthy diet and exercise.


When it comes to weight loss, there are a variety of options available, including prescription medications like Qsymia and phentermine.

Both drugs have their benefits, but it’s important to understand which one is best suited for your needs. Qsymia, for example, is often recommended for long-term treatment, while phentermine is generally better for shorter periods.

Both medications should be avoided during pregnancy and nursing. For those concerned about the risk of dependency, topiramate in Qsymia can help reduce this risk compared to phentermine.

While phentermine is more affordable and has fewer unpleasant withdrawal effects than Qsymia, it’s important to discuss your medical history with your doctor before taking either drug.

It’s worth noting that the safety of diet pills has only been established for adults 18 years of age and older.

I'm Jacob Foxx, a proud native of the outskirts of Chicago, Illinois. I was enamored with the expansive Star Trek universe and its promise of cutting-edge technology and space travel from a young age. This early fascination with science fiction sparked my imagination and laid the foundation for my writing career. Alongside my love for the cosmos, I developed a passion for fitness in my formative years.

This dual interest in the world of tomorrow and the pursuit of physical health has greatly informed my writing, allowing me to explore themes of human potential and the future of our species. As an author, I strive to blend these passions into compelling narratives that inspire readers to dream and to push their own boundaries.

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