Weight loss injections are prescription medications that mimic a gut hormone called GLP-1, which controls appetite and blood sugar. The two most widely prescribed options, semaglutide (Wegovy) and tirzepatide (Zepbound), have produced average weight reductions of 15% to 22% of body weight in clinical trials, making them the most effective non-surgical weight loss treatments available.
How These Injections Work
After you eat, your gut naturally releases a hormone called GLP-1 that signals your brain to feel full. Weight loss injections deliver a synthetic version of this hormone that lasts much longer than the natural one, keeping appetite suppressed throughout the week. The result is that you feel satisfied sooner during meals, think about food less between meals, and eat fewer calories overall without relying on willpower alone.
Tirzepatide (Zepbound) goes a step further by mimicking a second gut hormone called GIP in addition to GLP-1. This dual action appears to produce slightly greater weight loss on average, though both medications represent a major shift in how obesity is treated.
Available Medications
Semaglutide (Wegovy)
Wegovy is a once-weekly injection approved for weight management. In the original clinical trials, people taking the standard 2.4 mg dose lost an average of about 15.6% of their body weight over 72 weeks. A higher-dose version, Wegovy HD (7.2 mg), was approved in March 2026 and showed an average loss of 18.7% of body weight over the same period, compared to 3.9% for people taking a placebo.
Tirzepatide (Zepbound)
Zepbound is also a once-weekly injection. In its landmark trial, participants lost an average of 16% of body weight on the lowest dose, 21.4% on the middle dose, and 22.5% on the highest dose over 72 weeks. In real numbers, the highest dose translated to an average loss of about 52 pounds. People on placebo lost roughly 5 pounds over the same period.
Liraglutide (Saxenda)
Saxenda was one of the first GLP-1 injections approved for weight loss and requires a daily shot rather than a weekly one. It produces more modest results: an additional 9 to 13 pounds of weight loss compared to diet and exercise alone over one year. Because the newer weekly injections are more effective and more convenient, Saxenda is prescribed less frequently now, though it remains an option.
Who Qualifies for a Prescription
The FDA approves these medications for adults with a BMI of 30 or higher, or a BMI of 27 or higher if you also have at least one weight-related health condition such as type 2 diabetes, high blood pressure, or high cholesterol. Your doctor will assess your medical history and may check for conditions that could make these drugs unsafe, such as a personal or family history of a rare type of thyroid cancer called medullary thyroid carcinoma.
These injections are meant to be used alongside dietary changes and increased physical activity, not as a standalone fix. People who combine the medication with lifestyle changes tend to see the best and most lasting results.
What Taking Them Looks Like
All of these medications are self-administered using a prefilled pen, similar to an insulin pen. You inject just under the skin in your thigh, abdomen, or upper arm. The needle is short and thin, and most people describe it as a quick pinch rather than a painful experience.
You don’t start at the full dose. Every weight loss injection follows a gradual dose-escalation schedule, typically increasing every four weeks, to give your body time to adjust and reduce side effects. For Saxenda, the starting dose increases weekly until reaching the target after about five weeks. For the weekly injections like Wegovy and Zepbound, the full escalation takes several months.
Rotating your injection site each week is important. Injecting in the same spot repeatedly can cause fatty tissue to build up under the skin, which interferes with how well the medication absorbs. Some people also report fewer stomach-related side effects when injecting into the thigh rather than the abdomen, so experimenting with location can help with tolerability.
Common Side Effects
Nausea is the most frequently reported side effect and tends to be worst during the dose-escalation phase. Vomiting, diarrhea, and constipation are also common. For most people, these gastrointestinal symptoms improve after the first few weeks at each dose level, which is exactly why the titration schedule exists.
Less common but more serious risks include pancreatitis (inflammation of the pancreas causing severe abdominal pain), gastroparesis (where the stomach empties much more slowly than normal), bowel obstruction, and gallstone attacks. These are rare but worth knowing about. If you develop severe, persistent stomach pain, that warrants prompt medical attention.
“Ozempic face” has become a widely discussed cosmetic concern. Rapid weight loss from any cause can lead to a gaunt or aged appearance in the face as fat pads shrink. This isn’t a drug side effect in the traditional sense but rather a visible consequence of significant weight loss happening faster than the skin can adjust.
Cost and Insurance Coverage
At list price, these medications are expensive. Wegovy has carried a list price of around $1,350 per month, while Zepbound has been listed at roughly $1,086 per month. However, pricing has been shifting. Through newer government pricing programs, the cost can drop to around $350 per month for eligible purchasers. Medicare beneficiaries may pay a copay of roughly $50 per month under current pricing agreements.
Private insurance coverage varies widely. Some plans cover weight loss injections fully, others require prior authorization and documented failure of other weight loss methods, and some exclude them entirely. Manufacturer savings programs and patient assistance programs can significantly reduce out-of-pocket costs for people with commercial insurance, so it’s worth checking directly with the drugmaker if your coverage is limited.
What These Injections Don’t Cover
There is one other injectable approved for obesity, but it works completely differently and treats an extremely rare condition. Setmelanotide (Imcivree) targets specific genetic mutations that cause severe obesity from childhood. It is only prescribed for people with confirmed genetic conditions like Bardet-Biedl syndrome or specific gene deficiencies, and it is not effective for general obesity. If you’re reading this article, it almost certainly doesn’t apply to you, but it’s worth mentioning so you have the full picture if you encounter the name.
What Happens When You Stop
Weight regain after stopping these medications is common. Studies consistently show that people regain a significant portion of their lost weight within a year of discontinuing treatment. This happens because the injections suppress appetite through an ongoing hormonal mechanism. Once the medication leaves your system, the appetite signals return to their previous levels. For this reason, many doctors now view these medications as long-term or even indefinite treatments for obesity, much like blood pressure medications are used continuously to manage hypertension rather than taken for a short course and stopped.