Weight loss medications are prescription drugs that help people lose weight by reducing appetite, changing how the body absorbs food, or altering hormones that regulate hunger and fullness. The field has expanded dramatically in recent years, with newer injectable and oral drugs producing significantly more weight loss than older options. Most require a BMI of 30 or greater, or a BMI of 27 or greater with a weight-related health condition like high blood pressure or type 2 diabetes.
GLP-1 and Related Injections
The biggest shift in obesity treatment came with a class of drugs that mimic gut hormones called incretin hormones. These hormones signal your brain to feel full, slow the emptying of your stomach, and help regulate blood sugar. The result is a substantial reduction in appetite that most people describe as simply not thinking about food as much.
Semaglutide, sold as Wegovy for weight loss, was approved in 2021 and quickly became the most talked-about obesity drug in decades. It’s a once-weekly injection that activates one of these hormone receptors (GLP-1). An oral version of Wegovy also became available at the end of 2025, giving people a pill option for the same medication. Semaglutide is also sold under the brand name Ozempic for type 2 diabetes, though the two are dosed differently.
Tirzepatide, sold as Zepbound for weight loss, was approved in 2023 and activates two hormone receptors instead of one (GLP-1 and GIP). In clinical trials, tirzepatide produced weight loss ranging from 15% to nearly 21% of body weight over 72 weeks. That means a person starting at 250 pounds could expect to lose roughly 38 to 52 pounds on the higher end. Tirzepatide is also available as Mounjaro for type 2 diabetes.
Orforglipron, sold as Foundayo, is a newer oral GLP-1 medication approved for adults with obesity or overweight plus at least one weight-related health condition. Unlike semaglutide, which is a large peptide molecule, orforglipron is a small-molecule drug, which made it easier to develop as a daily pill from the start.
Common Side Effects of GLP-1 Drugs
The most frequent complaint with GLP-1 medications is gastrointestinal discomfort, especially during the first weeks as the dose gradually increases. A 2025 RAND Corporation survey of U.S. adults who had taken a GLP-1 drug found that about 52% reported nausea, roughly 34% reported diarrhea, and about 20% reported vomiting at some point during treatment. These numbers reflect self-reported experiences and include side effects of all severity levels. For most people, the nausea is worst early on and fades as the body adjusts. Starting at a low dose and increasing slowly is the standard approach to minimize these effects.
Older Oral Medications
Several oral weight loss drugs have been available for years. They generally produce more modest weight loss than the newer injectable options, but they cost far less and work well for some people.
Phentermine is the most widely prescribed weight loss pill in the U.S. and has been around for decades. It works as an appetite suppressant by increasing levels of certain brain chemicals that reduce hunger. It’s typically prescribed for short-term use (a few weeks to a few months) and is available for as little as $17 per month with discount pricing. Because it’s a stimulant, it can raise heart rate and blood pressure.
Phentermine-topiramate (Qsymia) combines phentermine with an extended-release form of topiramate, a drug originally used for seizures and migraines. The combination targets appetite through two different pathways. Treatment starts at a low dose for 14 days, then increases. If you haven’t lost at least 3% of your body weight after 12 weeks, your provider may increase the dose further. If you still haven’t lost at least 5% after another 12 weeks at the higher dose, the medication is typically discontinued because meaningful results are unlikely at that point. A generic version became available in 2025, bringing the price down to around $63 per month.
Naltrexone-bupropion (Contrave) pairs two existing drugs: one used for alcohol and opioid dependence and another used as an antidepressant. Together, they affect brain pathways involved in cravings and reward. This medication isn’t an option for everyone. It’s contraindicated for people with uncontrolled high blood pressure, a history of seizures, bulimia or anorexia nervosa, or those taking opioid medications. People who are discontinuing alcohol, benzodiazepines, or certain other medications should also avoid it.
Orlistat (Xenical, Alli) works completely differently from every other weight loss drug. Instead of acting on appetite, it blocks enzymes in your gut that break down dietary fat. About 30% of the fat you eat passes through unabsorbed. The trade-off is digestive side effects: oily stools, gas, and urgent bowel movements, particularly after high-fat meals. Alli, the lower-dose over-the-counter version, is available for around $55.
How Much They Cost
Price varies enormously depending on whether you’re taking a generic older drug or a brand-name injectable. Here’s a snapshot of discount pricing as of early 2026:
- Phentermine: around $17/month
- Qsymia (generic): around $63/month
- Wegovy: around $149/month
- Foundayo: around $149/month
- Contrave: around $199/month
- Zepbound: around $1,072/month
- Saxenda: around $1,369/month
These are discount prices, not insurance copays. Insurance coverage for weight loss medications has expanded but remains inconsistent. Some plans cover GLP-1 drugs only for diabetes, not for obesity. Others have added obesity coverage in response to the growing evidence base. Manufacturer savings programs and pharmacy discount cards can reduce out-of-pocket costs significantly, but eligibility rules change frequently.
Who Qualifies
The standard eligibility thresholds for prescription weight loss medication are a BMI of 30 or higher, or a BMI of 27 or higher if you also have a weight-related condition such as type 2 diabetes, high blood pressure, high cholesterol, or sleep apnea. Your provider will also consider your medical history to determine which specific medication is appropriate. For instance, someone with a seizure history would not be a candidate for naltrexone-bupropion, while someone with a personal or family history of a rare thyroid cancer called medullary thyroid carcinoma would need to avoid GLP-1 drugs.
These medications are designed to be used alongside changes in diet and physical activity, not as a replacement. Clinical trials for every approved weight loss drug include lifestyle modifications as part of the treatment protocol. The drugs make it easier to eat less by reducing hunger and cravings, but they work best when combined with sustainable habits.
What Happens When You Stop
One of the most important things to understand about weight loss medications is that weight regain after stopping is common, particularly with GLP-1 drugs. Studies consistently show that people regain a significant portion of lost weight within a year of discontinuation. This is not a failure of willpower. The biological signals that drive hunger and weight regain are powerful, and the medications work by overriding those signals. For many people, obesity treatment with these drugs is long-term or even indefinite, similar to how blood pressure medication controls hypertension without curing it.
This reality is part of why cost and insurance coverage matter so much. A medication that works well but costs over $1,000 per month and needs to be taken indefinitely presents a very different calculation than a short-term prescription. It’s also why some providers use a stepwise approach: starting with less expensive options and moving to newer drugs only when needed.