The landscape of weight loss treatments is rapidly evolving, with new medications and approaches emerging frequently. This article delves into the role of primary care physicians (PCPs) in prescribing weight loss medications, exploring the available options, guidelines, and considerations for patients seeking medical assistance in their weight management journey.
The Obesity Epidemic and the Role of Pharmacotherapy
Obesity is a widespread and chronic disease affecting a significant portion of the population. In Canada, nearly two-thirds of the population is classified as overweight or obese. In the United States, the problem is similarly pervasive, leading to various health complications. Recognizing obesity as a chronic condition is crucial, and PCPs are often at the forefront of managing such conditions.
Weight management is analogous to the treatment of other chronic medical conditions such as hypertension or diabetes. The process typically begins with setting a realistic goal, such as an initial weight loss of 5% to 10%, which can lead to significant improvements in health and function and reduce risk factors. A multimodal treatment strategy is then implemented, starting with lifestyle modifications, including dietary changes, behavior modifications, and regular physical activity. When lifestyle changes alone are insufficient to achieve the desired results, pharmacotherapy may be considered.
Guidelines and Recommendations for Pharmacological Interventions
The Canadian Task Force on Preventive Health Care (CTFPHC) released guidelines in 2015 regarding the prevention of weight gain and the use of behavioral and pharmacologic interventions for managing overweight and obesity in adults in primary care. These guidelines suggest that PCPs should not routinely offer pharmacologic interventions for weight loss. However, they acknowledge that pharmacotherapy might be warranted in some cases of obesity, provided the benefits and risks are carefully weighed.
Despite these recommendations, the CTFPHC guidelines have been criticized for deemphasizing the role of PCPs in obesity treatment. Given the high prevalence of overweight and obese individuals and the potential health benefits of even modest weight loss, PCPs should feel equipped to assist patients in achieving weight loss through lifestyle modifications and, when appropriate, pharmacotherapy.
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FDA-Approved Weight Loss Medications
Before 2012, there were limited options for FDA-approved weight loss medications. However, the pharmacological treatment of obesity has since become a rapidly evolving field. In the 2020s, glucagon-like peptide-1 receptor agonists (GLP-1 receptor agonists) gained significant popularity and media attention. These medications, along with dual receptor agonists like Mounjaro (indicated for type 2 diabetes) and Zepbound (indicated for obesity), have expanded the toolkit available to healthcare providers.
Several FDA-approved medications can aid in weight loss when combined with physical activity and a healthy diet. These medications work through various mechanisms to help patients lose weight and maintain that loss:
- Orlistat (Xenical, Alli): This lipase inhibitor blocks the body from absorbing some of the fat consumed in the diet. It is available both as a prescription medication (Xenical) and in an over-the-counter formulation (Alli).
- Phentermine-Topiramate (Qsymia): This combination medication reduces appetite and cravings. It is often considered for individuals with migraines and obesity.
- Naltrexone-Bupropion (Contrave): This medication combines an opioid receptor antagonist with an antidepressant to affect the pleasure-reward areas of the brain, thereby decreasing cravings and appetite.
- Liraglutide (Saxenda): This long-term medication makes the body feel full by acting on hormones that send signals from the gut to the brain. It is administered as a daily injection.
- Semaglutide (Wegovy, Ozempic): Semaglutide, known as Ozempic and Wegovy, mimics a naturally occurring hormone called glucagon-like-peptide-1 (GLP-1). GLP-1 has several functions in the body. After you eat, your GLP-1 level rises, and the molecules travel to your brain, to help regulate food intake. In your brain, Ozempic and Wegovy bind to receptors that have to do with satiety, so they increase your feeling of fullness. In essence, your brain tells your body it’s full, even though you’re consuming less food and calories. Ozempic and Wegovy work to slow gastric emptying, so you can’t put as much food into your stomach as you can normally. The drug also helps the beta cells in your pancreas make more insulin. Wegovy is approved specifically for weight loss.
- Tirzepatide (Zepbound, Mounjaro): Tirzepatide is a dual GIP and GLP-1 receptor agonist that suppresses appetite, improves satiety, and supports metabolic health. It has demonstrated impressive weight loss results in clinical trials.
GLP-1 Receptor Agonists: A Closer Look
GLP-1 receptor agonists have revolutionized the medical approach to weight loss. These medications mimic the naturally occurring hormone GLP-1, which plays a crucial role in regulating appetite and food intake. Semaglutide, available as Ozempic and Wegovy, and liraglutide (Saxenda) are examples of GLP-1 receptor agonists.
How GLP-1s Work
GLP-1s work by:
- Increasing satiety: They bind to receptors in the brain that increase feelings of fullness, leading to reduced food consumption.
- Slowing gastric emptying: They slow down the rate at which food empties from the stomach, further contributing to a sense of satiety.
- Regulating insulin production: They help the beta cells in the pancreas produce more insulin, which can be particularly beneficial for individuals with prediabetes or type 2 diabetes.
Wegovy vs. Ozempic
While both Wegovy and Ozempic are made by the same company and contain semaglutide, they have different FDA clearances and dosages. Wegovy is specifically approved for weight loss in people 12 years and older, while Ozempic is typically prescribed for diabetes. However, Ozempic is sometimes used off-label for weight loss.
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Considerations for GLP-1 Use
- BMI Requirements: For prescribing Wegovy for weight loss, a person must have a body mass index (BMI) of 30 or greater. It’s also approved for use in people with a BMI of 27 or greater, who have an accompanying overweight- or obesity-related condition, such as high blood pressure or sleep apnea. 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.
- Insurance Coverage: One of the challenges with these medications is that obesity isn’t recognized as a disease in this country, so people can’t get them covered with insurance. Insurance coverage varies and will affect many patients’ choices about going on weight loss medications. The Kaiser Family Foundation estimates the annual net price of Wegovy at $13,600.
- Side Effects: Common side effects of GLP-1s include nausea, diarrhea, constipation, vomiting, headache, decreased appetite, dyspepsia, fatigue, dizziness, and abdominal pain. These side effects are usually mild and tend to decrease over time.
- Long-Term Use: GLP-1s are designed for long-term use in conjunction with a healthy diet and exercise. They are not meant to be stopped and restarted at will, as the dosing for some of these includes a long ramp-up period-up to five months-to reach full dosage.
The Weight-Loss Plateau and Potential Weight Regain
It’s important to note that there’s a weight-loss plateau. It doesn’t work forever, and at some point, your body reestablishes its set point, and your weight loss stops or plateaus. And, if you stop taking the drug altogether, your hunger returns, because you’ve changed the mechanism, and many people gain weight back.
Alternative and Emerging Treatments
Plenity
Plenity is a medical device, rather than a medication, that 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. 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 Holistic Approach
While medication can be a valuable tool in weight management, it is most effective when used as part of a comprehensive treatment plan. A holistic approach to weight loss includes:
- Lifestyle Modifications: This includes dietary changes, regular physical activity, and behavior modifications. Reducing caloric intake by 500 to 1000 kcal per day, engaging in moderate physical activity on most days of the week, and cognitive behavioral therapy are all important components of lifestyle modification programs.
- Medical Supervision: A healthcare professional can evaluate a patient's condition and medical history to determine which medication makes the most sense for their case. They can also monitor progress and side effects, ensuring the patient's safety and well-being.
- Supportive Relationships: Supportive relationships with family, friends, or support groups can provide encouragement and motivation throughout the weight loss journey.
The Role of Supplements and Vitamins
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.
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The Impact of Other Medications on Weight
It's important to consider the potential impact of other medications on weight. Some medications can be obesogenic or cause weight gain. For example, certain antidepressants, such as paroxetine, amitriptyline, doxepin, and imipramine, are associated with weight gain. On the other hand, bupropion (Wellbutrin) is considered weight-negative and is sometimes prescribed to assist in weight loss.
The Dangers of Counterfeit Medications
With the increasing demand for weight loss medications, there is a growing risk of 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, which are not FDA-approved.
Addressing Patient Concerns and Building Trust
Patients taking GLP-1s via an online provider may still need help managing side effects, monitoring comorbidities, making behavioral changes, or changing medications due to price, supply, or other reasons. In addition to conducting regular medication reconciliation to identify what prescription medications, non-prescription medications, and supplements a patient is taking, it is important to take steps to build trust and rapport. Assure patients they can be open and honest with you about their health concerns and any medications they might be taking or considering.