Weight-loss injections explained: which shots are FDA approved for weight vs diabetes, weekly vs daily, using a pen, side effects, muscle, stopping, cost and compounded risks.
Fact-checked against FDA labels and official sources; not yet reviewed by a licensed clinician. This page is education, not medical advice. Talk to your doctor before starting, stopping or changing any treatment.
Key takeaways
- Wegovy and Zepbound (weekly) and Saxenda (daily) are the injections FDA approved for chronic weight management; Ozempic and Mounjaro are approved for type 2 diabetes.[2]
- In SURMOUNT-5, average weight change at 72 weeks was -20.2% with tirzepatide and -13.7% with semaglutide.[10]
- The injections go under the skin of the stomach area, thigh or upper arm, with the site rotated each dose, according to the Wegovy label.[1]
- Weight tended to return after stopping in trials: +6.9% in STEP 4 and +14.0% in SURMOUNT-4 after switching to placebo.[12]
- Compounded semaglutide and tirzepatide are not FDA approved, and the FDA has reported dosing errors with them.[17]
In short: The weight-loss injections approved by the FDA for chronic weight management are Wegovy (semaglutide) and Zepbound (tirzepatide), taken once a week, and Saxenda (liraglutide), taken once a day; Imcivree is a daily injection only for specific rare genetic and hypothalamic forms of obesity (labels checked on 2026-10-06). Ozempic and Mounjaro are injections approved for type 2 diabetes, not for weight. All are prescription medicines used alongside eating and activity changes, and the decision to use one belongs to you and your clinician.
This hub is about the shots themselves: what they are, approved versus diabetes-only brands, weekly versus daily, what using a pen is like, side effects, muscle, stopping, cost, and how to avoid compounded and counterfeit products. For how the medicines work at the hormone level, see our GLP-1 guide; for pills, see weight-loss pills.
Start here: do these next 1-2-3
- Check the status badge. Make sure a product is FDA approved for weight management, not a diabetes brand used off label or a compounded copy. Our medications hub lists every approved option.
- Know the side effects before you start. Read GLP-1 side effects, including when to call a doctor.
- Plan for food, muscle and the long term. Use the protein calculator and read life after a GLP-1.
What weight-loss injections are
Today’s weight-loss injections are mostly gut-hormone medicines. Semaglutide and liraglutide activate the GLP-1 receptor; tirzepatide activates both the GIP and GLP-1 receptors. According to their labels, they reduce appetite and calorie intake and slow stomach emptying. Setmelanotide (Imcivree) works differently: it activates the MC4 receptor, part of a brain pathway that is disrupted in certain genetic conditions, and is labeled only for those conditions, confirmed by genetic testing, and for acquired hypothalamic obesity.
Approved for weight vs approved for diabetes
| Injection | Active ingredient | How often | FDA approved for (checked 2026-10-06) |
|---|---|---|---|
| Wegovy | Semaglutide | Weekly | Chronic weight management (adults; teens 12+); heart-risk reduction; MASH |
| Zepbound | Tirzepatide | Weekly | Chronic weight management (adults); obstructive sleep apnea with obesity |
| Saxenda | Liraglutide | Daily | Chronic weight management (adults; children 12+ over 60 kg with obesity) |
| Imcivree | Setmelanotide | Daily | Specific rare genetic obesity and acquired hypothalamic obesity only |
| Ozempic | Semaglutide | Weekly | Type 2 diabetes and related heart and kidney outcomes; not weight |
| Mounjaro | Tirzepatide | Weekly | Type 2 diabetes; not weight |
Because Ozempic is so widely searched, we explain the off-label question separately in Ozempic for weight loss. The difference between the two weekly weight brands is on Wegovy vs Zepbound.
Who they are labeled for
The weight-management labels for Wegovy, Zepbound and Saxenda cover adults with obesity, or adults with overweight and at least one weight-related condition, always together with a reduced-calorie diet and more physical activity; Wegovy and Saxenda also cover some teens 12 and older. The NIH describes prescription weight-management medicines as generally considered for adults with a BMI of 30 or more, or 27 or more with a condition such as high blood pressure or type 2 diabetes. The GLP-1 injections should not be used by people with a personal or family history of medullary thyroid carcinoma or MEN 2, or by anyone who has had a serious allergic reaction to the ingredient. Only a clinician who knows your history can say whether an injection fits you; our BMI calculator is a starting point, not a diagnosis.
Weekly or daily, and what using a pen is like
Wegovy and Zepbound are injected once a week; Saxenda and Imcivree once a day. The injections go under the skin, not into a muscle. The Wegovy label names the stomach area, thigh or upper arm and says to rotate the injection site with each dose. All the GLP-1 labels describe starting at a low dose and stepping up gradually, because that reduces stomach side effects; your prescriber decides the dose and the pace, and what to do if a dose is missed.
Storage matters. Wegovy and Zepbound single-dose pens are kept in the refrigerator and must not be frozen; if needed, the labels allow a limited time at room temperature (up to 28 days for Wegovy pens, and up to 21 days in total for Zepbound single-dose pens and vials). Zepbound also comes in vials and a multi-dose KwikPen, so the label asks that people be trained on the exact device they receive. Multi-dose pens must never be shared between people, even with a new needle.
How much weight people lose
In STEP 1, adults on weekly semaglutide 2.4 mg lost 14.9% of body weight on average over 68 weeks versus 2.4% on placebo. In SURMOUNT-1, weekly tirzepatide led to 15.0% to 20.9% by dose over 72 weeks versus 3.1%. In SURMOUNT-5, the head-to-head trial, average weight change was -20.2% with tirzepatide and -13.7% with semaglutide. Averages hide a wide range, and every trial combined the medicine with lifestyle support. The NIH notes that a loss of 5% to 10% may already improve health.
Side effects
Nausea, diarrhea, vomiting and constipation are the most common, mostly while doses are increasing; injection-site reactions also occur. The labels’ serious warnings include pancreatitis, gallbladder disease, low blood sugar with insulin or sulfonylureas, kidney injury from dehydration and aspiration during anesthesia, and the GLP-1 injections carry a boxed warning about thyroid C-cell tumors seen in rodents. Our GLP-1 side effects guide covers all of this and when to get help.
Muscle and protein
Part of any large weight loss is lean mass. The Zepbound label notes that tirzepatide lowers body weight with greater fat loss than lean mass loss, and a 2024 review found that the lean share of weight lost varies widely across GLP-1 studies. Eating enough protein and doing strength training are the usual ways people work to protect muscle. See muscle loss on GLP-1s, eating on a GLP-1 and our strength training guide.
Stopping and regain
These medicines are labeled for long-term use. In STEP 4, people switched from semaglutide to placebo regained 6.9% of body weight over 48 weeks; in SURMOUNT-4, people switched from tirzepatide to placebo regained 14.0% over about a year. The NIH notes that healthy eating and activity can help people regain less. Plan any change with your prescriber; our life after a GLP-1 guide covers what helps.
Cost, insurance and savings
Checked on October 6, 2026 on the manufacturers’ sites: Wegovy pens cost $349 a month self-pay through NovoCare Pharmacy ($199 for new patients’ first two fills of the two starting strengths through December 31, 2026; $399 for Wegovy HD), and Zepbound KwikPens $299 to $449 a month through Lilly, by dose. With commercial insurance that covers them, savings cards can bring the cost down to $25 a month. Medicare’s temporary GLP-1 Bridge (July 2026 through December 2027) covers Wegovy and Zepbound KwikPen for weight management with a $50 copay for people who meet its criteria. See Wegovy cost, Zepbound cost, the GLP-1 cost comparison and GLP-1 insurance coverage.
Compounded, counterfeit and “research” injections
Compounded semaglutide and tirzepatide are not FDA approved, and the FDA does not review them for safety, effectiveness or quality before sale. The FDA has received hundreds of adverse event reports for each, including dosing errors with vials and syringes, has warned three times about counterfeit Ozempic in the U.S. supply chain, and has warned about products sold “for research purposes.” Buy only with a prescription from a state-licensed pharmacy. Our compounded GLP-1 guide has the dated history and a checklist.
Injections compared
Side-by-side pages: Wegovy vs Zepbound, semaglutide vs tirzepatide, Ozempic vs Wegovy and injections vs pills. If you are weighing medicine against surgery, see GLP-1 vs bariatric surgery.
In this section
Compounded Semaglutide and Tirzepatide: what FDA says and the risksCompounded semaglutide and tirzepatide explained: not FDA approved, the dated shortage history, FDA safety reports, counterfeit…
GLP-1 Side Effects: common, serious and how they are managedGLP-1 side effects from the FDA labels: common digestive effects by brand, serious risks, the thyroid…
Muscle Loss on GLP-1s: protein, strength training and what studies showMuscle loss on GLP-1 medicines: what DXA studies found, lean mass vs muscle, who is at…
Ozempic for Weight Loss: what is approved, what is off label, what to askOzempic for weight loss explained: what the FDA label covers, what off-label use means, Ozempic vs…Related guides
GLP-1 Side Effects: common, serious and how they are managedGLP-1 side effects from the FDA labels: common digestive effects by brand, serious risks, the thyroid…Compounded Semaglutide and Tirzepatide: what FDA says and the risksCompounded semaglutide and tirzepatide explained: not FDA approved, the dated shortage history, FDA safety reports, counterfeit…Muscle Loss on GLP-1s: protein, strength training and what studies showMuscle loss on GLP-1 medicines: what DXA studies found, lean mass vs muscle, who is at…Ozempic for Weight Loss: what is approved, what is off label, what to askOzempic for weight loss explained: what the FDA label covers, what off-label use means, Ozempic vs…Tools for this topic
Latest research
How to Read a Weight-Loss Study Headline in 5 StepsFive questions to ask before believing a weight-loss headline: who was studied, how many, how long,…
What’s Coming in 2027: Weight-Loss Treatments Awaiting FDA DecisionsWeight-loss treatments awaiting FDA decisions in 2027: CagriSema, retatrutide, survodutide, MariTide and more, with filing dates,…
Fake and Counterfeit Weight-Loss Drugs: How to Spot ThemCounterfeit Ozempic has reached U.S. pharmacies three times. The FDA alerts, what online test buys found,…Questions to ask a professional
- Is an injection a reasonable option for me, and which one fits my health history?
- Would a weekly or a daily injection work better for me, and how do I use the device?
- Which side effects should make me call you?
- What will it cost with my insurance, and is prior authorization needed?
- How do we protect muscle, and what happens if I stop?
Frequently asked questions
What are the weight-loss injections called?
The ones FDA approved for chronic weight management are Wegovy (semaglutide, weekly), Zepbound (tirzepatide, weekly) and Saxenda (liraglutide, daily). Imcivree is approved only for specific rare genetic and hypothalamic forms of obesity. Ozempic and Mounjaro are diabetes medicines.
Do weight-loss injections hurt?
They use a small needle under the skin. Injection-site reactions such as redness or itching are listed as side effects on the labels. A pharmacist or nurse can show you how to use the specific pen or vial.
Which is better, weekly or daily?
It depends on the medicine, the person and their routine. Weekly options mean fewer injections; daily ones are different molecules with their own results and side effects. Your prescriber can explain the trade-offs for you.
How much do weight-loss shots cost?
On 2026-10-06, self-pay was $349 a month for Wegovy pens and $299 to $449 for Zepbound KwikPens through the manufacturers. With covering commercial insurance, savings cards can lower it to $25. Medicare has a temporary $50 Bridge for eligible people.
Are cheaper compounded shots the same?
No. Compounded semaglutide and tirzepatide are not FDA approved and are not reviewed by the FDA for safety, effectiveness or quality.
References
- WEGOVY (semaglutide) injection and tablets: prescribing information. Novo Nordisk, via DailyMed, 2026. (accessed October 7, 2026) Drug label
- ZEPBOUND (tirzepatide) injection: prescribing information. Eli Lilly and Company, via DailyMed, 2026. (accessed October 7, 2026) Drug label
- SAXENDA (liraglutide) injection: prescribing information. Novo Nordisk, via DailyMed, 2026. (accessed October 6, 2026) Drug label
- IMCIVREE (setmelanotide) injection: prescribing information. Rhythm Pharmaceuticals, via DailyMed, 2026. (accessed October 6, 2026) Drug label
- OZEMPIC (semaglutide) injection: prescribing information. Novo Nordisk, via DailyMed, 2026. (accessed October 7, 2026) Drug label
- MOUNJARO (tirzepatide) injection: prescribing information. Eli Lilly and Company, via DailyMed, 2026. (accessed October 7, 2026) Drug label
- Prescription Medications to Treat Overweight & Obesity. National Institute of Diabetes and Digestive and Kidney Diseases (NIH). (accessed October 7, 2026) Government page
- Wilding JPH, Batterham RL, Calanna S, et al.. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). New England Journal of Medicine, 2021. doi:10.1056/NEJMoa2032183 · PMID 33567185 · NCT03548935 (accessed October 7, 2026) Randomized trial
- Jastreboff AM, Aronne LJ, Ahmad NN, et al.. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine, 2022. doi:10.1056/NEJMoa2206038 · PMID 35658024 · NCT04184622 (accessed October 7, 2026) Randomized trial
- Aronne LJ, Horn DB, le Roux CW, et al.. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5). New England Journal of Medicine, 2025. doi:10.1056/NEJMoa2416394 · PMID 40353578 · NCT05822830 (accessed October 6, 2026) Randomized trial
- Rubino D, Abrahamsson N, Davies M, et al.. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance (STEP 4). JAMA, 2021. doi:10.1001/jama.2021.3224 · PMID 33755728 · NCT03548987 (accessed October 7, 2026) Randomized trial
- Aronne LJ, Sattar N, Horn DB, et al.. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. JAMA, 2024. doi:10.1001/jama.2023.24945 · PMID 38078870 · NCT04660643 (accessed October 7, 2026) Randomized trial
- Neeland IJ, Linge J, Birkenfeld AL. Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies. Diabetes, Obesity and Metabolism, 2024. doi:10.1111/dom.15728 · PMID 38937282 (accessed October 6, 2026) Review
- Wegovy at NovoCare Pharmacy: self-pay prices. Novo Nordisk (NovoCare Pharmacy). (accessed October 7, 2026) Other
- Zepbound coverage and savings. Eli Lilly and Company. (accessed October 6, 2026) Other
- Medicare GLP-1 Bridge: information for providers. Centers for Medicare and Medicaid Services. (accessed October 7, 2026) Government page
- FDA’s concerns with unapproved GLP-1 drugs used for weight loss. U.S. Food and Drug Administration, 2026. (accessed October 7, 2026) Government page
- FDA warns consumers not to use counterfeit Ozempic found in U.S. drug supply chain. U.S. Food and Drug Administration, 2025. (accessed October 7, 2026) Government page
Facts checked on October 6, 2026
Educational information, not medical advice. Talk with a qualified healthcare professional about your own situation. In an emergency call 911.