Medications for Weight Loss
Obesity is a complex condition, and there isn't a single definition or threshold for when it becomes a medical concern. Generally, obesity is characterized by excessive fat accumulation that poses a risk to overall health. This risk is systemic—affecting nearly every organ in the body—and is a major factor in the development of conditions like high blood pressure and type 2 diabetes.
The most common screening tool for obesity is the Body Mass Index (BMI), which calculates a number based on your height and weight. However, BMI doesn’t directly measure body fat and can be affected by factors such as body shape, muscle mass, and ethnicity. Therefore, healthcare providers often use BMI as a preliminary marker, relying on their clinical judgment to diagnose obesity.
Obesity is now recognized as a disease and, like other diseases, it requires compassionate and evidence-based medical treatment. In addition to being a risk factor for conditions like type 2 diabetes, high cholesterol, and high blood pressure, it’s also linked to certain cancers. Alongside smoking, obesity is one of the most critical modifiable factors for improving long-term health outcomes.
Loosing Weight
Because weight gain is influenced by a wide range of factors, weight loss must also take a multifaceted approach. Although various “fad diets” promise quick results, the most reliable method for sustainable weight loss remains the same: eating a balanced diet and increasing physical activity. These lifestyle changes are the first step in any weight loss plan.
If lifestyle adjustments alone are not sufficient after a reasonable period, medications may be considered as an additional tool. However, it’s important to remember that even with prescription weight loss medications, continuing a healthy diet and regular exercise remains essential for long-term success.
Weight Loss Medications
The FDA approves weight loss medications for:
- Adults with a BMI over 30 kg/m
- Adults with a BMI over 27 kg/m² who have at least one weight-related condition (e.g., high blood pressure or type 2 diabetes)
One exception is Imcivree, which is approved for individuals aged 6 and older with obesity caused by specific genetic conditions, such as proopiomelanocortin, protein convertase subtilisin/kexin type 1, or leptin receptor deficiency, confirmed through genetic testing.
Stimulant-Based Medications
Contrave (bupropion-naltrexone)
Contrave combines bupropion, an antidepressant that can also reduce appetite, and naltrexone, typically used to treat alcohol and opioid addiction. This combination helps regulate appetite and cravings by targeting areas of the brain involved in hunger and reward.
Studies indicate that patient who took Contrave, along with diet and exercise can achieve at least 5% of their body weight after one year of treatment.
Common side effects include: nausea, constipation, insomnia, and increased heart rate.
Qsymia (phentermine-topiramate)
Qsymia is a combination of two drugs, phentermine and topiramate. Phentermine functions as an appetite suppressant. It stimulates the release of certain chemicals in the brain (hypothalamus) that reduce hunger and increase feelings of fullness. The role of Topiramate, typically used to treat epilepsy and migraines, is less understood. It is thought to be involved in decreasing appetite as well as increasing “fullness”. It affects certain pathways in the brain associated with eating behavior and appetite control.
On average, people using Qsymia alongside diet and exercise can lose between 5-10% of their body weight over the course of one year.
Common side effects include: dry mouth, taste changes, insomnia, and increased heart rate.
GLP-1 Receptor Agonists
Saxenda (liraglutide) and Wegovy (semaglutide)
These medications mimic the gut hormone GLP-1 (glucagon-like peptide-1), which regulates appetite by signaling the brain to reduce hunger, slow gastric emptying, and promote a feeling of fullness.
The main difference between the two drugs is dosing frequency. Both Saxenda and Wegovy are administered as self-injections: Saxenda is a daily injection, while Wegovy is a weekly injection. Wegovy is generally a higher-potency medication compared to Saxenda.
Common side effects for both drugs include: nausea, vomiting, diarrhea, constipation, and abdominal pain. These side effects are mostly related to their action on the gastrointestinal system.
Efficacy: When combined with a healthy diet and exercise, both Saxenda and Wegovy can lead to significant weight loss. Clinical trials have shown that patients taking Saxenda can lose at least 5% of their body weight. Wegovy has demonstrated more impressive results, with patients losing an average of 10% of their body weight and some losing up to 15%.
Lipase Inhibitors
Xenical (orlistat) and Alli (orlistat)
Xenical and Alli both contain the active ingredient orlistat, which works as a lipase inhibitor. These medications block the enzyme lipase, which is responsible for breaking down fats in the intestines. By inhibiting this enzyme, orlistat prevents approximately 30% of dietary fats from being absorbed into the body. The undigested fat is then eliminated through bowel movements, leading to a caloric deficit.
Xenical is a prescription medication containing 120 mg of orlistat, while Alli is available over-the-counter at 60 mg.
Common side effects for both drugs include: gastrointestinal issues such as oily stools, flatulence, and frequent bowel movements.
Efficacy: Clinical studies have shown that patients who take Xenical along with diet and exercise can lose about 5-10% of their body weight over a year. Patients who take Alli along with diet and exercise can lose about 3-5% of their body weight. The effectiveness of both medications depends on adherence to a low-fat diet to minimize gastrointestinal side effects and enhance weight loss results.
Imcivree (Setmelanotide): MC4 Receptor Agonist
Imcivree is a melanocortin 4 receptor (MC4R) agonist, specifically designed for individuals with rare genetic conditions that cause dysfunction in the MC4 pathway. These genetic disorders disrupt the brain's ability to regulate hunger and energy expenditure, leading to severe obesity starting in early childhood. Imcivree acts by re-balancing this system, allowing the brain to send appropriate signals of satiety and energy use, helping control body weight.
Administration: Imcivree is administered as a subcutaneous injection, typically once daily. Patients undergoing treatment with Imcivree require regular monitoring by a healthcare provider to track weight loss progress and manage potential side effects.
Efficacy: Patients treated with Imcivree experienced an average weight loss of 10-15% of their body weight over a year. Many individuals report a significant reduction in hunger and cravings, which plays a central role in the long-term success of weight management with this medication.
Imcivree is effective only in individuals with certain genetic mutations related to the melanocortin system. It is not intended for general obesity management but is a breakthrough therapy for those with genetically driven obesity.
Although Imcivree is generally well-tolerated, it can cause some side effects, primarily related to its action on the melanocortin system. Common side effects include: skin darkening (hyperpigmentation), nausea, vomiting, injection site reactions, and depression.