The best weight loss injections available in the US in 2026 are FDA-approved GLP-1 and dual GIP/GLP-1 receptor agonist medications, led by tirzepatide (Zepbound), semaglutide (Wegovy), and liraglutide (Saxenda). Ranked by efficacy in the pivotal phase 3 trials, tirzepatide produced the greatest average total body weight loss, followed by semaglutide, then liraglutide. Two other injectable GLP-1 drugs, dulaglutide and exenatide, are FDA-approved for type 2 diabetes only and not for weight management, so they sit alongside this group rather than in the obesity-approved tier.
This guide ranks each option by its trial results, explains how it works and its main side effects, and notes what each one is approved for. All of them are prescription-only. Results vary, and the right choice depends on your health history, which is a decision to make with a licensed healthcare provider.
Only three injectable medications currently carry an FDA approval specifically for chronic weight management in adults: tirzepatide, semaglutide, and liraglutide. The ranking below orders these three by efficacy from their phase 3 trials, then covers two more injectable GLP-1 drugs approved only for diabetes. For all of them, results are strongest when the medication is paired with a reduced-calorie diet and more physical activity, and weight tends to come back after stopping, which is why they are treated as long-term medications.
Tirzepatide is a dual GIP/GLP-1 receptor agonist, a single molecule that activates both the GIP and the GLP-1 receptors. Working on two hormone pathways affects appetite, energy use, and glucose metabolism together, and it ranks first on weight loss.
In the 72-week SURMOUNT-1 trial of 2,539 adults without diabetes, average total body weight loss was 15.0 percent at the 5 mg dose, 19.5 percent at 10 mg, and 20.9 percent at 15 mg, compared with 3.1 percent on placebo. About 91 percent of participants on the 15 mg dose lost at least 5 percent of their body weight. In the head-to-head SURMOUNT-5 trial, tirzepatide produced a 20.2 percent average reduction versus 13.7 percent for semaglutide over 72 weeks.
It is dosed once weekly under the skin, starting at 2.5 mg and increasing by 2.5 mg every four weeks toward a maintenance dose of 5, 10, or 15 mg. Zepbound is FDA-approved for chronic weight management in adults with obesity or overweight with a weight-related condition, and also for moderate-to-severe obstructive sleep apnea in adults with obesity. Common side effects include nausea, vomiting, diarrhea, constipation, and injection-site reactions. A cardiovascular outcomes trial (SURPASS-CVOT) is still ongoing, so heart-outcome data are not yet available.
Semaglutide is a selective GLP-1 receptor agonist that increases satiety, slows gastric emptying, and improves insulin secretion. It ranks second on weight loss, but it is the only one of these drugs with proven heart benefits.
In the 68-week STEP 1 trial of 1,961 adults without diabetes, average weight loss was 14.9 percent with semaglutide 2.4 mg versus 2.4 percent on placebo, and more than half of participants lost at least 15 percent of their body weight. In the STEP 8 head-to-head trial, semaglutide produced a 15.8 percent average reduction versus 6.4 percent for liraglutide.
The SELECT trial is what sets it apart. In 17,604 adults with established cardiovascular disease and overweight or obesity but without diabetes, weekly semaglutide 2.4 mg reduced major adverse cardiovascular events by 20 percent. It is still the only anti-obesity injection with a completed cardiovascular outcomes trial showing this benefit in people without diabetes, which can shape the choice for patients who already have heart disease. It is dosed once weekly, raised every four weeks from 0.25 mg to 2.4 mg. Common side effects include nausea, vomiting, diarrhea, and constipation.
Liraglutide is a GLP-1 receptor agonist in the same class as semaglutide, but with a shorter half-life that requires a once-daily injection rather than weekly dosing. In the 56-week SCALE Obesity and Prediabetes trial of 3,731 adults, average weight loss was 8.0 percent versus 2.6 percent on placebo, and about 63 percent of participants lost at least 5 percent of their body weight.
It is meaningfully less effective than both semaglutide and tirzepatide, and network analyses consistently rank it below the two. It is dosed daily under the skin, starting at 0.6 mg and increasing by 0.6 mg each week to a maintenance dose of 3.0 mg. Saxenda is FDA-approved for adults and adolescents 12 and older with obesity or overweight with a related condition. The daily schedule and lower efficacy mean it is often reserved for specific situations, but it remains a valid, FDA-approved option to discuss with a provider. Common side effects mirror the class: nausea, diarrhea, constipation, and vomiting.
The other two drugs people often mention are GLP-1 receptor agonists as well: dulaglutide (Trulicity) and exenatide (Byetta and the extended-release Bydureon). Both are FDA-approved for type 2 diabetes only, not for weight management. They can cause some weight loss as a side effect, which is why they come up, but they are not indicated for obesity, so using them that way would be off-label.
Because they were studied for blood sugar rather than weight, the weight loss tends to be modest next to the obesity-approved drugs, and they are not direct substitutes for tirzepatide, semaglutide, or liraglutide. They are listed here to round out the full set of injectable options. If a provider does consider one of them outside its approved use, that is a clinical decision that calls for a careful discussion of risks and benefits. Talk to a healthcare provider before assuming any diabetes medication is right for weight loss.
There is no single best weight loss shot for everyone. Tirzepatide leads on average weight loss in trials, semaglutide is the only option with proven cardiovascular benefit in people who already have heart disease, and liraglutide offers a daily, longer-established alternative. Real-world data in more than 18,000 patients support the trial findings, with tirzepatide associated with greater weight loss than semaglutide at 3, 6, and 12 months and similar rates of gastrointestinal side effects.
The right fit depends on your medical history, any heart or thyroid conditions, other medications you take, insurance coverage, supply, and whether a weekly or daily injection suits your routine. Weight loss also tends to be greater in people without type 2 diabetes across all of these drugs. Since every one of them is prescription-only and carries class warnings, including a boxed warning about thyroid C-cell tumors, a proper medical evaluation is the right way to choose.
Side effects are worth weighing too. All of these injections share a similar gastrointestinal profile. Nausea, vomiting, diarrhea, and constipation are the most common, and they tend to be mild to moderate and to ease as the dose goes up slowly over the first weeks and months. A provider can adjust how fast you titrate, suggest timing and diet changes, and watch for the less common risks such as gallbladder problems and pancreatitis. Cost and insurance coverage differ a lot between products and pharmacies, and supply has been uneven for some doses, so practical access often shapes the decision as much as the trial numbers do. A telehealth evaluation is one way to work through these factors and settle on an option you can realistically start and stay on.
What is the most effective weight loss injection?
In the pivotal phase 3 trials, tirzepatide (Zepbound) produced the largest average weight loss, followed by semaglutide (Wegovy), then liraglutide (Saxenda). The most effective option for any individual still depends on health history and how the body responds, which a provider can assess.
Are all five injections FDA-approved for weight loss?
No. Only tirzepatide, semaglutide, and liraglutide are FDA-approved for chronic weight management. Dulaglutide and exenatide are approved for type 2 diabetes only, so using them for weight loss would be off-label.
Which weight loss injection is best for someone with heart disease?
Semaglutide 2.4 mg is the only anti-obesity injection with a completed cardiovascular outcomes trial (SELECT) showing reduced major cardiac events in people with established cardiovascular disease and obesity. This is a factor a provider may weigh, but the decision is individual.
Do these injections work without diet and exercise?
They are FDA-approved for use with a reduced-calorie diet and more physical activity, not on their own. The trial results were achieved alongside lifestyle changes, and results vary from person to person.
Do you regain weight after stopping?
Yes, weight regain is common after stopping any of these drugs, which is why current guidelines treat them as long-term medications. Your provider can help you plan a maintenance approach.
Learn more: FDD Weight Loss Program | Eligibility quiz
