Comparison
What is the best injection for weight loss? Latest options explained
By the TreatmentMD editorial team
Medically reviewed by Christopher Stephenson, MD
Key takeaways
- Wegovy® (semaglutide) and Zepbound® (tirzepatide) are two commonly used weekly injections approved for weight management.
- In a head-to-head study, people using Zepbound® (tirzepatide) lost more weight on average than people using Wegovy® (semaglutide), but side effects and cost can tip the choice the other way for some people.
- A licensed provider will help you determine which GLP-1 medication is right for your medical history and weight loss goals.
By the TreatmentMD editorial team
If you've searched "best injection for weight loss," you've probably noticed there isn't one simple answer. The right shot depends on your health history, your budget, and how your body responds.
Here's a look at what's approved right now, what's new, and how to think through your options with your provider.
01At a glance
A quick look at the options
Wegovy® and Zepbound® are two commonly used weekly injections approved for weight management.
They're for adults with obesity, or adults with overweight who also have a weight-related health problem like high blood pressure.
The table below compares them with two related diabetes medicines.
| Injection | Active ingredient | FDA-approved for | How it's taken | Average weight loss in studies |
|---|---|---|---|---|
| Wegovy® | semaglutide | Chronic weight management | Weekly injection or once daily pill | About 14% of body weight1U.S. Food and Drug AdministrationSourceWegovy® (semaglutide) FDA-approved prescribing information, Novo Nordisk (current version).All sources |
| Ozempic® | semaglutide | Type 2 diabetes (not weight loss) | Weekly injection | Not FDA-approved for weight management |
| Zepbound® | tirzepatide | Chronic weight management | Weekly injection | About 20% of body weight2U.S. Food and Drug AdministrationSourceZepbound® (tirzepatide) FDA-approved prescribing information, Eli Lilly and Company (current version).All sources |
| Mounjaro® | tirzepatide | Type 2 diabetes (not weight loss) | Weekly injection | Not FDA-approved for weight management |
02The options
Each option, explained
Wegovy® (semaglutide)
Wegovy® works by mimicking a gut hormone called GLP-1. It slows digestion and turns down appetite signals in the brain. Semaglutide, its active ingredient, has been in clinical use longer than tirzepatide.2U.S. Food and Drug AdministrationSourceZepbound® (tirzepatide) FDA-approved prescribing information, Eli Lilly and Company (current version).All sources3U.S. Food and Drug AdministrationSourceOzempic® (semaglutide) FDA-approved prescribing information, Novo Nordisk (current version), initial U.S. approval date.All sources
Zepbound® (tirzepatide)
Zepbound® targets two gut hormones instead of one (GLP-1 and GIP). That dual action is one reason it tends to produce more weight loss for many people. In a study that put Zepbound® and Wegovy® head-to-head (in adults with obesity, without type 2 diabetes), participants lost about 20% of their body weight on Zepbound® compared with about 14% on Wegovy®.4Eli Lilly and CompanySourceEli Lilly and Company, SURMOUNT-5 complete results news release, May 11, 2025; published in The New England Journal of Medicine.Open the source All sources
What about Ozempic® (semaglutide) and Mounjaro® (tirzepatide)?
These have the same active ingredients as Wegovy® and Zepbound®, but they are FDA-approved only for type 2 diabetes, not weight loss. Using them for weight loss alone is an off-label use, meaning outside their approved purpose.
What about a pill instead of a shot?
If needles are the main hurdle for you, a daily pill version of semaglutide is also approved for weight management.1U.S. Food and Drug AdministrationSourceWegovy® (semaglutide) FDA-approved prescribing information, Novo Nordisk (current version).All sources In one study, people taking the pill lost about 14% of their body weight on average over about 15 months.5The New England Journal of MedicineRandomized trial · 2025OASIS 4People lost 13.6% of their weight on the Wegovy pill, against 2.2% on placebo, over 64 weeks.307 people · 64 weeks. Adults with obesity, or overweight and a weight-related condition, without diabetes. Funded by Novo Nordisk.Oral semaglutide at a dose of 25 mg in adults with overweight or obesity. Wharton S, et al., 2025.Read the study All sources Individual results vary. Another oral option includes Foundayo™ (orforglipron), which was approved in April 2026.
03Choosing
How they compare, and what each is best for
There's no single "best" injection for everyone. The best option for you depends on your health needs, body, and health history.
Zepbound® (tirzepatide) has shown the strongest average weight loss in comparison studies, and may suit someone with a higher amount of weight to lose.
Semaglutide, the ingredient in Wegovy®, has been in clinical use longer than tirzepatide.
Your medical history, insurance coverage, and how your body tolerates the medication all matter more than any one number on a chart.
04Side effects
Side effects & safety
Common side effects of semaglutide and tirzepatide injections include:
These usually ease over the first few months as your body adjusts.
Side effects often peak after each dose increase and gradually improve as your body adapts, with most mild reactions resolving over time.6The New England Journal of MedicineRandomized trial · 2022SURMOUNT-1Mean body weight fell 20.9 percent at the 15 mg dose against 3.1 percent on placebo over 72 weeks.2,539 people · 72 weeks. Adults with BMI 30 or above, or 27 or above with at least one weight-related complication, without diabetes.Tirzepatide once weekly for the treatment of obesity. Jastreboff AM, et al., 2022.Read the study All sources
05Cost
Cost & access
The cost of these brand-name weight loss injections has historically run over $1,000 a month, but the price profile shifted in 2026.
A federal pricing agreement sets a Medicare price of $245 a month for Wegovy®, Zepbound®, Ozempic®, and Mounjaro®.7The White HouseSourceThe White House / HHS fact sheet on Medicare and Medicaid GLP-1 pricing agreement, November 6, 2025.Open the source All sources
Out-of-pocket pricing varies by source: a federal marketplace and the manufacturer's direct-purchase programs list starting promotional prices generally between $200 and $450 for the first two months depending on brand and dose, with increased standard monthly costs for Ozempic® and Wegovy® around $350+ and Zepbound® around $346+.8The White HouseSourceTrumpRx.gov cash-pay pricing announcement, February 2026.Open the source All sources
Since actual cost depends on individual insurance, dose, and pharmacy, this is general market information rather than a quote. Check current pricing directly for your specific situation.
Frequently asked questions.
Is tirzepatide better than semaglutide?
Not necessarily.
Zepbound® (tirzepatide) showed more average weight loss in a recent large study, but individual results may vary.
Some people tolerate one drug better than the other.
How much weight can I expect to lose?
Averages from clinical trials of GLP-1 weight loss drugs range from roughly 14% to 21% of body weight, but individual results vary depending on dose, how long you stay on treatment, and your own biology.9The New England Journal of MedicineRandomized trial · 2025SURMOUNT-5People lost 20.2% of their weight on tirzepatide and 13.7% on semaglutide, in the only trial to compare the two directly.751 people · 72 weeks. Adults with obesity, without diabetes. Open label, funded by Eli Lilly.Tirzepatide as compared with semaglutide for the treatment of obesity. Aronne LJ, et al., 2025.Read the study All sources
Do these injections work without diet and exercise changes?
GLP-1 medications are approved as an add-on to a reduced-calorie diet and more physical activity, not as a replacement for them.
Patients should be willing to make lifestyle changes as outlined by their licensed provider to see results.
The bottom line
Wegovy® (semaglutide) and Zepbound® (tirzepatide) are two commonly used weekly injections approved for weight management.
Zepbound® (tirzepatide) tends to produce more weight loss on average, but the right choice depends on your health, tolerance, and cost.
A licensed provider can help you weigh these factors and check current pricing and coverage options.
By the TreatmentMD editorial team
Medical disclaimerThis content is for informational purposes only and is not medical advice. Always consult a qualified healthcare provider before starting any weight-loss program or medication. Individual results may vary.
Sources
- 1Wegovy® (semaglutide) FDA-approved prescribing information, Novo Nordisk (current version).
- 2Zepbound® (tirzepatide) FDA-approved prescribing information, Eli Lilly and Company (current version).
- 3Ozempic® (semaglutide) FDA-approved prescribing information, Novo Nordisk (current version), initial U.S. approval date.
- 4Eli Lilly and Company, SURMOUNT-5 complete results news release, May 11, 2025; published in The New England Journal of Medicine. investor.lilly.com
- 5Wharton S, et al. "Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity" (OASIS 4), New England Journal of Medicine, September 2025;393(11):1077-1087. Average weight loss of 13.6% at 64 weeks (treatment-policy analysis). doi.org
- 6Jastreboff AM, et al. "Tirzepatide Once Weekly for the Treatment of Obesity" (SURMOUNT-1), New England Journal of Medicine, July 2022. doi.org
- 7The White House / HHS fact sheet on Medicare and Medicaid GLP-1 pricing agreement, November 6, 2025. whitehouse.gov
- 8TrumpRx.gov cash-pay pricing announcement, February 2026. whitehouse.gov
- 9Aronne LJ, et al. "Tirzepatide as Compared with Semaglutide for the Treatment of Obesity" (SURMOUNT-5), New England Journal of Medicine, May 2025. doi.org
Product information
- Zepbound® (tirzepatide) is a prescription-only injectable medication FDA-approved for chronic weight management in adults with obesity, or adults with overweight who have at least one weight-related medical condition. It is also approved for the treatment of moderate to severe obstructive sleep apnea in adults with obesity, and should be used in combination with a reduced-calorie diet and increased physical activity.
- Ozempic® (semaglutide) is a prescription-only injectable medication approved by the U.S. Food and Drug Administration (FDA) for the treatment of type 2 diabetes. It is not FDA-approved for weight loss; however, weight reduction has been observed in some individuals with type 2 diabetes using the medication.
- Mounjaro® (tirzepatide) is a prescription-only injectable medication FDA-approved for the treatment of type 2 diabetes. It is not FDA-approved for weight loss; however, weight reduction has been observed in some individuals using the medication.
- Wegovy® (semaglutide) is a prescription-only injectable medication FDA-approved for chronic weight management in adults with obesity, or adults with at least one weight-related medical condition, when used alongside a reduced-calorie diet and increased physical activity.
- All medications require a medical evaluation and prescription from a licensed healthcare provider. Individual results may vary.
Important safety information
- Compounded semaglutide and tirzepatide are prepared by state-licensed pharmacies and are not FDA approved. The FDA does not review their safety, effectiveness or quality, and clinical trial results for brand-name drugs do not carry over to them.
- Semaglutide and tirzepatide carry a boxed warning for a risk of thyroid C-cell tumors, based on animal studies, and are not for anyone with a personal or family history of medullary thyroid carcinoma (MTC) or MEN2, or who is pregnant. Other warnings include pancreatitis, gallbladder problems, and a higher risk of low blood sugar when combined with insulin or a sulfonylurea. The most common side effects are digestive, such as nausea, vomiting, diarrhea and constipation.
- This is a high-level summary, not a complete list. A licensed clinician will review your health history to decide whether a GLP-1 medication is right for you.
