The landscape of pharmacological obesity treatment is rapidly evolving. It’s crucial for healthcare providers to stay informed about the latest developments. The availability of FDA-approved weight loss medications was limited before 2012. However, the 2020s witnessed the surge in popularity of glucagon-like peptide-1 receptor agonists (GLP-1 receptor agonists). Mounjaro, a dual receptor agonist indicated for type 2 diabetes, and Zepbound, indicated for obesity, followed. In 2024, a significant number of adults turned to GLP-1s for weight loss. As the options for weight loss medications expand, patients are increasingly curious about the most potent and suitable prescription for their needs. This article examines the available medical weight loss options, their efficacy, and considerations for individual suitability.
Determining Candidacy for Weight Loss Medications
The starting point for determining if someone is a candidate for weight loss medications is their Body Mass Index (BMI). The guidelines for tirzepatide (Zepbound) and semaglutide (Wegovy) state that a patient should have a BMI of 30 or a BMI of 27 with weight-related health problems. For each individual case, the doctor and patient should discuss the patient’s current health issues, other medications, and family medical history. Older AOMs also have indications based on BMI and may be contraindicated for use with certain other medications.
Approved Medications for Long-Term Use
Several weight management medications are designed for long-term use. Those approved by the FDA for long-term use include orlistat (Xenical, Alli), phentermine-topiramate (Qsymia), naltrexone-bupropion (Contrave), liraglutide (Saxenda), semaglutide (Wegovy, Ozempic), and tirzepatide (Zepbound, Mounjaro).
First-Generation Anti-Obesity Medications (AOMs)
It can be easy to overlook first-generation AOMs, but these may be appropriate for some patients, especially when cost is a factor. As with many medications, some weight loss drugs have been on the market longer, have generic alternatives, and tend to be more affordable. GLP-1s are notoriously costly. The Kaiser Family Foundation estimates the annual net price of Wegovy at $13,600. and are not covered by insurance. Insurance coverage varies and will affect many patients’ choices about going on weight loss medications.
GLP-1 Receptor Agonists: Semaglutide (Wegovy, Ozempic)
Wegovy is a brand name for semaglutide, a GLP-1 receptor agonist. It was FDA-approved in 2021. It is administered as an injection and approved for use in adults and children aged 12 years or more with obesity (BMI ≥30 for adults, BMI ≥ 95th percentile for age and sex for children) or some adults with excess weight (BMI ≥27) who also have weight-related medical problems. The dose must be increased gradually over 16 to 20 weeks to arrive at the 2.4 mg dosage. This progression can help to alleviate side effects, which include gastrointestinal symptoms, headache, dizziness, and fatigue. It is intended to be used indefinitely, in combination with a healthy diet and exercise. Ozempic may be a more familiar name to some patients. Semaglutide also is used to help control type 2 diabetes.
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Dual Receptor Agonists: Tirzepatide (Zepbound, Mounjaro)
Zepbound is approved to treat obesity in adults with a BMI of 30 or greater. It is both a GLP-1 and a GIP receptor agonist. Like semaglutide, it works by reducing appetite and is meant to be used in combination with diet and exercise to lose weight. In the SURMOUNT-1 trial, adults with obesity or overweight (without diabetes) taking tirzepatide achieved up to 22.5% average body weight reduction at 72 weeks. Tirzepatide is a dual GIP and GLP-1 receptor agonist that suppresses appetite, improves satiety, and supports metabolic health. In addition to impressive weight loss, studies show improvements in cardiovascular risk factors and metabolic markers. provides Zepbound (tirzepatide) single-dose vial access for the 7.5 mg, 10 mg, 12.5 mg, and 15 mg doses-starting with refill eligibility within 45 days of delivery. Mounjaro is indicated for type 2 diabetes.
Liraglutide (Saxenda, Victoza)
Liraglutide is a daily injectable medication that acts on hormones that send signals from the gut to the brain to make the patient feel full quicker and decrease hunger signals. Doses start at 0.6 mg to 3 mg a day. Some patients may lose 5-10% of body weight, especially with the higher dose of liraglutide. Liraglutide is also approved for Type 2 Diabetes, under the brand name Victoza. Side effects include nausea, diarrhea, constipation, vomiting, headache, decreased appetite, dyspepsia, fatigue, dizziness, abdominal pain, increased lipase, and renal insufficiency.
Phentermine and Phentermine-Topiramate (Qsymia)
Phentermine is the oldest and most widely used weight loss medication. It was originally used as a short-term medication to jump-start weight loss, but now newer medical guidelines have added it to long-term therapy. Side effects include headache, overstimulation, high blood pressure, insomnia, rapid or irregular heart rate, and tremor. Phentermine-topiramate is a combination of a weight-loss drug called phentermine and an anticonvulsant called topiramate. Phentermine has the potential to be misused because it acts like a stimulant drug called an amphetamine. Other possible side effects include an increase in heart rate and blood pressure, insomnia, constipation, and nervousness. Topiramate can be combined with phentermine to decrease appetite and cravings. Adults with migraines and obesity are good candidates for this weight-loss medication. Some patients may lose an average of 5-10% of body weight. Daily doses with four strengths start at 3.75 mg/23 mg to 15 mg/92 mg. Side effects include abnormal sensations, dizziness, altered taste, insomnia, constipation, and dry mouth. Phentermine by itself (Adipex-P, Lomaira) also is used for weight loss. It's one of four similar weight-loss drugs approved for use for less than 12 weeks, called short-term use.
Naltrexone-Bupropion (Contrave)
Naltrexone-bupropion combines an opioid receptor antagonist with an antidepressant to affect the pleasure-reward areas of the brain and thereby decrease cravings and appetite. Start with a daily dose of one 8/90 mg tablet and gradually increase to four tablets a day. The most common side effects include nausea, constipation, headache, vomiting, dizziness, insomnia, dry mouth, and diarrhea. Bupropion (Wellbutrin), an aminoketone, is considered weight-negative and is prescribed both to assist in weight loss and to treat depression. The exception is orlistat. Bupropion-naltrexone is a combination drug. Naltrexone is used to treat alcohol and opioid addiction. Bupropion is a drug to treat depression, called an antidepressant, and a drug to help people stop smoking, called a quit-smoking aid. Like all antidepressants, bupropion carries a warning about suicide risk. Bupropion-naltrexone can raise blood pressure. So your provider will need to check your blood pressure regularly at the start of treatment.
Orlistat (Xenical, Alli)
Orlistat is a lipase inhibitor that comes in a capsule. Undigested fat is then passed through the body. Some patients may lose about 5% of their body weight. An over-the-counter formulation is available at 60 mg capsules with each fat-containing meal. Orlistat can cause side effects such as passing gas and having loose stools. You need to follow a low-fat diet when taking this medicine. In rare cases, people have had serious liver injury with orlistat. The only over-the-counter medicine for weight loss currently approved by the FDA is Alli (orlistat).
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Setmelanotide
Setmelanotide is a melanocortin-4 receptor agonist indicated for chronic weight management in adult and pediatric patients six years and older, with obesity due to certain rare genetic disorders. Setmelanotide doesn't treat any of the gene problems that cause these conditions. But it can help you lose weight. It can lessen your appetite and make you feel fuller. You take setmelanotide as a daily shot. Never give setmelanotide to a child under 6 years old.
Plenity
A medical device rather than a medication, Plenity was FDA-cleared in 2019 for people with a BMI of 25 to 40. It consists of a capsule that releases a biodegradable, super-absorbent hydrogel into the stomach. The gel helps to increase satiety, enabling the person to eat less.
Future Medications
With fervent consumer demand for weight loss medications, combined with rising obesity rates, more medications are bound for the market in the coming years. Pharmaceutical platform Ozmosi predicts one to two GLP-1 launches annually starting in 2026. specifically for obesity. Lilly is developing at least two new options. The first, orforglipron, is an oral GLP-1 inhibitor that completed a Phase 3 clinical trial in early 2025. It could provide a welcome alternative for people who do not want injections. Phase 3 results expected soon. at 36 weeks. The other, retatrutide, targets GLP-1, GIP, and glucagon. At this writing, it is in Phase 3 clinical trials. In Phase 2, participants lost up to 24.2% of body weight at 48 weeks. Amgen is developing MariTide, a monoclonal antibody designed to increase GLP-1 receptor activity while reducing GIP receptor activity. The once-monthly injection entered Phase 3 clinical trials in March 2025. Researchers continue to study hormones that play a role in appetite for other ways to target obesity with medication. Those of interest include not only GLP-1, but also peptide tyrosine-tyrosine (PYY) and cholecystokinin (CCK).
The Importance of a Comprehensive Treatment Plan
FDA-approved anti-obesity medications (AOMs) are safe, evidence-based therapies that target specific physiology to improve the disease and are most effective when used as part of a comprehensive treatment plan. A treatment plan for obesity can comprise multiple forms of treatment, including medications, diet, exercise, and/or surgery. All weight loss medications work best in the context of a healthy eating plan and exercise. Losing a significant amount of weight is a personal journey, and it can feel challenging to navigate alone. If traditional diets and exercise plans haven’t worked for you, it’s important to know you still have options. Medical weight loss is a nonsurgical treatment program guided by a member of our clinical team, such as a physician or nurse practitioner. Follow up visits: You come back to meet with us regularly. This may be weekly or monthly. During these visits, we measure your progress and help you set new goals. Medication: If you are not seeing results, we may prescribe medications to help curb your appetite. Education and support: During every office visit, we give you tips and information to help you stay motivated and take control of your weight loss journey. You may learn about new foods, portion control and goal setting. Support every step of the way: Together, we help you implement the lifestyle changes needed to achieve and maintain your goals. Once you decide to enroll in the medical weight loss program, you’ll participate in a medical exam and regular appointments with a medical doctor or APRN.
Weight Regain After Discontinuation
Most people regain weight if AOMs are discontinued. AOMs may counter the effects of metabolic adaptation and prevent weight regain. After weight reduction, the body metabolically adapts, often causing an increase in hunger hormones and a decrease in satiety hormones and resting metabolic rate, all of which can contribute to weight regain. GLP-1s are not meant to be stopped and restarted at will. The dosing for some of these includes a long ramp-up period-up to five months-to reach full dosage.
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Average Weight Loss and Individual Variation
The average weight loss varies from 5% to 21%, with some people losing more and some people losing less. Taking these drugs for a year can mean a loss of total body weight of 3% to 12% more than that lost with lifestyle changes alone. That may not seem like a lot. But losing 5% to 10% of your total weight and keeping it off can have important health benefits.
Considerations and Precautions
Several factors must be considered before starting medical weight loss.
Counterfeit Medications
Some online healthcare providers claim to sell Ozempic, Wegovy, or Zepbound at reduced prices. However, the FDA warns against buying medications from any source other than a state-licensed pharmacy. In April 2025, they banned the sale of “counterfeit” semaglutide and tirzepatide. These medications are not made or packaged by the original manufacturers. Instead, they are compounded medications. Compounded versions of medications are made by compounding pharmacies, often to tailor a medication to specific patient needs, like an allergy to an inactive ingredient. Compounded medications are not FDA-approved. due to shortages. Some patients have taken these alternatives, which are generally more affordable, without ill effects. has received 520 reports of adverse events associated with compounded semaglutide and 480 reports of adverse events associated with compounded tirzepatide (as of April 30, 2025).
Potential Side Effects
Mild side effects, such as nausea, constipation and diarrhea, are common. They may lessen over time. Rarely, serious side effects can happen. That's why it's important to ask your health care provider about all treatment choices. They can also interfere with hormonal birth control.
Impact of Antidepressants on Weight
There are many medications that can be obesogenic or cause weight gain. Antidepressants are broken down into categories: selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants, monoamine oxidase inhibitors (MAO inhibitors), and others. In the SSRI group, paroxetine shows the highest associated weight gain. Weight-positive medications in the tricyclic antidepressant category include amitriptyline, doxepin, and imipramine.
Supplements
While no specific vitamin or supplement is considered a “treatment” for obesity or overweight, certain ones help support metabolic health. For example, studies suggest that calcium and vitamin D may play a role in regulating belly fat. have been proposed for how this works.