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4 FDA-Approved Weight Loss Medications: Is One Right for You?


  • The Food and Drug Administration (FDA) has approved four weight loss medications, which are available by prescription only.
  • Most weight loss medications work by controlling your appetite or by making you feel fuller for longer periods of time. 
  • Prescription weight loss medications require ongoing monitoring and work best when balanced with a healthy diet and exercise routine.
  • Prescription weight loss drugs aren’t right for everyone, so you should speak with a provider about the best options for your health and lifestyle.
  • The FDA has now cleared a new type of weight loss aid, the Plenity weight loss device.

Some people may benefit from taking an FDA-approved weight loss medication. These four medications are only available by prescription and are approved for use in some adults. You might also wish to explore the Plenity weight loss device, a new type of weight loss aid that’s safe and effective and cleared by the FDA. 

FDA-Approved Weight Loss Medications

The FDA has approved four prescription weight loss medications for long-term use. These drugs are typically taken for 12 weeks or longer. Your provider can help you to choose the best drug and the best course of treatment for your health goals.

The four weight loss medications approved by the FDA include:

Are Weight Loss Medications Right for You?

Weight loss medications aren’t right for everyone. Talk to your provider about your health history and your goals for losing weight. They will help you decide if these weight loss aids are right for you.

You may be a candidate for prescription weight loss medications if:

  • You haven’t been able to lose weight with traditional diet and exercise changes
  • Your body mass index (BMI) is over 30
  • Your BMI is over 27 and you have a medical condition related to obesity

You shouldn’t take prescription weight loss medications if you are pregnant, trying to become pregnant, or if you’re nursing. You should also tell all your medical providers if you’re taking a prescription weight loss drug.

Are Weight Loss Medications Effective?

Research shows that taking prescription weight loss medication results in significant weight loss compared to placebo. You’re likely to achieve greater results when you combine weight loss medication with healthy lifestyle changes. 

Weight loss drugs vary in how they work in the body. They work by one or more mechanism, such as:

  • Helping to reduce your appetite
  • Helping you to feel full for longer periods of time
  • Reducing the amount of fat you absorb from food


Bupropion-naltrexone is a combination of drugs that works by reducing appetite and food cravings. It’s specifically approved for use by obese adults and those who have weight-related health conditions.

Bupropion is an antidepressant medication that can reduce appetite. Naltrexone is used to block the effects of opioids or alcohol in people with substance use disorder. It can also be used to help control hunger and food cravings. 

Research shows bupropion-naltrexone to be effective at significantly reducing weight loss and in helping people to maintain that weight loss long term. It cannot be used to treat weight-related conditions, such as diabetes or high blood pressure. It should be used alongside a balanced diet and exercise routine to manage weight. 

Warnings and Risks — Bupropion-naltrexone

Bupropion-naltrexone can cause serious side effects and can make some health conditions worse. This medication is only approved for use in people 18 years and older. 

Bupropion-naltrexone might alter drug-screening results by causing a false positive. 

Don’t take bupropion-naltrexone if you:

  • Are pregnant, nursing, or planning to become pregnant
  • Are allergic or have ever had an allergic reaction to bupropion or naltrexone
  • Have an eating disorder
  • Have seizures
  • Have uncontrolled high blood pressure
  • Use opioids 
  • Use other forms of bupropion
  • Recently stopped using alcohol, opioids, seizure medications, or sedatives 

Bupropion-naltrexone can affect your mood. Tell your provider if you have a history of mood disorders or mental illness before taking this medication. Monitor yourself for symptoms of anxiety, depression, or suicidal thoughts while taking it. 

Side Effects — Bupropion-naltrexone

Talk to your provider about potential side effects before taking bupropion-naltrexone. Older adults are more likely to experience adverse side effects. 

Potential side effects include:

  • Constipation 
  • Diarrhea
  • Dizziness
  • Dry mouth
  • Headache
  • Nausea 
  • Sleep problems
  • Vomiting 

Drug Interactions — Bupropion-naltrexone

Talk to your doctor about potential drug interactions prior to using bupropion-naltrexone, as it can interact with several classes of drugs. Drinking alcohol and eating high-fat meals can increase your risk of seizures while taking this medication.


Liraglutide is a weight loss medication that can also be used to manage diabetes. This medication is unlike others, as it’s only available as an injection. Liraglutide works by slowing emptying the stomach and decreasing appetite. 

Research shows that liraglutide consistently helps to manage weight, control glucose, and improve cardiovascular health. It works best when combined with a balanced diet and exercise routine. 

Warnings and Risks — Liraglutide

Liraglutide may place you at higher risk of thyroid problems, such as thyroid tumors. It may also be unsafe to use this medication while breastfeeding. Talk to your provider about your personal and family health history before taking liraglutide. 

Side Effects — Liraglutide

The most common side effects from liraglutide include: 

  • Constipation
  • Diarrhea
  • Dizziness
  • Headache
  • Low blood sugar
  • Nausea, vomiting, or loss of appetite
  • Rash
  • Tiredness or fatigue

Liraglutide can also cause serious side effects, including: 

  • Dehydration
  • Gallbladder or pancreas problems
  • Racing or pounding heartbeat
  • Signs of a thyroid tumor, such as swelling or a lump in your neck, trouble swallowing, or a hoarse voice
  • Suicidal thoughts
  • Sudden changes to mood or behavior

Tell your provider immediately if you experience any of these reactions.

Drug Interactions — Liraglutide

Talk to your provider about potential drug interactions prior to using liraglutide. It should not be taken with other medications like albiglutide, dulaglutide, exenatide, and others. It may also interact with other prescription drugs, over-the-counter medications, vitamins, and herbal products. 


Woman at a table with fruits and veggies

Orlistat (Xenical) works differently than other weight loss medications by reducing the amount of fat your body absorbs when you eat. It’s only approved for use in adults who are overweight or obese.

Orlistat is one piece of a complete treatment regimen that includes a balanced diet, exercise, and weight control routine. You should follow a low-fat diet while taking orlistat. You should also take orlistat exactly as directed.

When taken as directed, orlistat is effective at helping people lose weight, lower their BMI, shrink their waist circumference, and lower cholesterol levels. A reduced-strength version (Alli) is available without a prescription. 

Warnings and Risks — Orlistat

Orlistat can cause serious side effects and worsening of certain health conditions. Speak to your provider about your health history prior to taking this medication. You should carefully follow all instructions from your provider, including your dietary restrictions. 

Don’t take orlistat if you:

  • Are pregnant
  • Are not overweight or obese
  • Have a digestive disorder
  • Have gallbladder problems

Side Effects — Orlistat

The most common side effect of orlistat is gastrointestinal (GI) upset. This is a side effect of the fat-blocking mechanism, which indicates the medication is working. These side effects are typically temporary.

GI side effects may include:

  • Gas and flatulence
  • Inability to control bowel movements
  • Increased number of bowel movements
  • Loose stools
  • Oily discharge or spotting
  • Oily or fatty stools
  • Orange or brown oil in your stool
  • Stomach pain, nausea, or rectal pain

Orlistat can cause severe side effects in some people. Stop taking orlistat and talk to your provider immediately if you experience:

  • Blood in your urine or problems urinating
  • Fatigue or shortness of breath 
  • Signs of kidney problems
  • Signs of liver problems, such as jaundice
  • Severe lower back pain
  • Severe stomach pain
  • Swelling in your feet or ankles

Drug Interactions — Orlistat

Talk to your provider about potential drug interactions prior to using orlistat, as it can interact with many classes of drugs. Orlistat may also interact with certain vitamin and mineral supplements.


Phentermine-topiramate is a combination weight loss medications. It works by decreasing appetite and helping you to feel fuller longer. It can be used to treat obesity related to diabetes, high blood pressure, or high cholesterol. 

Phentermine can be used short term on its own for weight loss. Topiramate is an anticonvulsant when used on its own. The combined medication is prescribed alongside a balanced diet and exercise routine for the most effective weight loss results. 

Phentermine-topiramate has been shown to reduce weight by an average of five to ten percent in approximately 70 percent of patients. However, this medication can cause severe side effects and should be used as part of a complete treatment plan. 

Warnings and Risks — Phentermine-topiramate

Phentermine-topiramate is not safe for everyone to use. It’s unsafe for use in people with glaucoma or thyroid problems. It also has the potential to be misused because it works similarly to amphetamines. 

You shouldn’t use this medication if you are pregnant or planning to become pregnant. This medication can cause birth defects, including cleft lip and cleft palate in newborns.

Some people experience suicidal thoughts while taking Phentermine-topiramate. Talk to your provider immediately if you notice sudden changes in mood or if you experience suicidal thoughts while taking this medication. 

Ketogenic or “ketosis” diets that are high in fat and low in carbohydrates can increase the risk of metabolic acidosis while taking this medication. 

Side Effects — Phentermine-topiramate

Talk to your provider about potential side effects before taking Phentermine-topiramate. It can cause severe side effects in some people. Monitor yourself for new or worsening symptoms and speak to your provider immediately if you notice severe side effects.

Severe side effects may include:

  • Confusion, trouble concentrating, or memory problems
  • Changes to mood or mental health
  • Fast or pounding heartbeats while resting
  • Seizures
  • Signs of kidney stones
  • Suicidal thoughts
  • Vision problems 

Other side effects may include:

  • Constipation
  • Dizziness
  • Dry mouth
  • Headache
  • Increased heart rate
  • Increased blood pressure
  • Nervousness
  • Sleep problems

Drug Interactions — Phentermine-topiramate

Talk to your doctor about potential drug interactions prior to using phentermine-topiramate, as it may interact with prescription medications. It should not be used with MAO inhibitor medications (isocarboxazid, linezolid, phenelzine, others). You may wish to avoid drinking alcohol while taking this medication, as alcohol can worsen side effects. 

Plenity Weight Loss Device

Tying shoelaces on a sneaker

Weight loss drugs aren’t right for everyone. They require ongoing maintenance and may cause serious side effects. Fortunately, there is another safe and effective weight loss method cleared by the FDA. 

Plenity is not a medication, but a new type of weight loss aid — a weight loss device. It’s been researched for use in overweight and obese adults and cleared to use by people who are only moderately overweight. Plenity has been shown to work best when combined with a healthy diet and exercise routine. 

Plenity is an oral capsule made from two natural ingredients — cellulose and citric acid. This combination of ingredients works in the GI tract to make you feel fuller for longer periods of time. 

Find Support with eDrugstore

Talk to one of our U.S.-licensed physicians to find out if Plenity is right for you. We make it easy to talk to healthcare professionals about weight loss and other men’s health concerns, such as erectile dysfunction, sexual health, and hair loss. 

Take advantage of our free online consultation to order your medications online or by calling 1-800-467-5146. Virtual health visits and shipping are always free.

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