Four injections carry FDA approval for weight loss in the United States: semaglutide (Wegovy), tirzepatide (Zepbound), liraglutide (Saxenda), and setmelanotide (Imcivree) for rare genetic causes of obesity. Two more, Ozempic and Mounjaro, are diabetes drugs prescribed off-label for weight loss. A third group, including HCG and lipotropic shots, has no approval and no reliable evidence behind it.
At Unify Care, we regularly evaluate patients for weight loss injections across Southern California. Our clinical experience is what this guide draws on. Below is every type, what the trials showed, how often you inject, what each costs, and how to tell a real option from a marketing one.
Who Qualifies for a Weight Loss Injection
For adults, the traditional criteria are a BMI of 30 or higher, or a BMI of 27 or higher with at least one weight-related condition such as type 2 diabetes, high blood pressure, high cholesterol, or sleep apnea.
For adolescents, Wegovy and Saxenda are approved from age 12 for those with obesity, defined by a BMI at or above the 95th percentile for age and sex. Zepbound is approved for adults only.
A BMI number is only the starting point. A physician also considers your other diagnoses, current medications, family history, and goals. Anyone who is pregnant, planning pregnancy, or has a personal or family history of medullary thyroid carcinoma or MEN 2 should not use these drugs.
Types of Weight Loss Injections
FDA-Approved Weight Loss Injections Follow
These four are the only injections the FDA has cleared for weight management, which means each went through trials designed around weight and carries dosing instructions written for that purpose.
Semaglutide (Wegovy and Wegovy HD)
How it works
Semaglutide copies GLP-1, a gut hormone your body releases after meals. It signals fullness to your brain, slows how fast food leaves your stomach, and quiets cravings. The result is that you feel satisfied with less food and stay full longer after eating.
How to take it
Wegovy is a weekly injection given under the skin of the abdomen, thigh, or upper arm. Dosing starts at 0.25 mg and climbs through 0.5, 1, and 1.7 mg, arriving at the 2.4 mg maintenance dose at week 17. Wegovy HD delivers 7.2 mg weekly and requires four weeks at 2.4 mg first. A daily oral pill version of Wegovy launched in January 2026 for adults who prefer not to inject.
Side effects
Nausea affected 44% of patients at the 2.4 mg dose in trials. Around 6.8% stopped treatment over side effects. Other common effects include vomiting, diarrhea, constipation, and stomach pain. These typically improve as the body adjusts, and slowing the titration pace helps significantly.
Effectiveness
In the STEP 1 trial of 1,961 adults with obesity, Wegovy 2.4 mg produced an average loss of 14.9% of body weight over 68 weeks, against 2.4% on placebo. That works out to roughly 34 pounds versus 6 pounds on placebo. Wegovy HD at 7.2 mg produced 20.7% average weight loss over 72 weeks in the STEP UP trial, with 31.2% of participants losing at least a quarter of their body weight.
Tirzepatide (Zepbound)
How it works
Tirzepatide activates two gut hormone receptors rather than one: GIP alongside GLP-1. That dual action produces stronger appetite suppression and slower digestion than GLP-1 alone, which is why it delivers the largest average weight loss of any approved injection.
How to take it
Zepbound is a weekly injection for adults. Dosing starts at 2.5 mg and rises in 2.5 mg steps every four weeks to a maximum of 15 mg. It can be injected into the abdomen, thigh, or upper arm.
Side effects
Digestive side effects affected 56% of patients across the weight loss trials, against 30% on placebo. Nausea, vomiting, diarrhea, and constipation are the most common. As with semaglutide, holding a lower dose longer usually resolves these better than switching drugs.
Effectiveness
In SURMOUNT-1, adults without diabetes lost an average of 15.0% on 5 mg, 19.5% on 10 mg, and 20.9% on 15 mg over 72 weeks, against 3.1% on placebo. More than half of the 15 mg group lost at least a fifth of their body weight. Zepbound also holds a second FDA approval for moderate to severe obstructive sleep apnea in adults with obesity, making it the first drug approved for that condition.
Tirzepatide vs Semaglutide
Tirzepatide (Zepbound) produced greater average weight loss than semaglutide (Wegovy) in the one direct head-to-head trial, SURMOUNT-5, but the two drugs also differ in side effects, cost, and approved uses. For the full comparison, read our guide: Tirzepatide vs Semaglutide.
Liraglutide (Saxenda)
How it works
Liraglutide works the same way as semaglutide, mimicking GLP-1 to signal fullness and slow digestion. Its shorter duration in the body is why it requires a daily injection rather than a weekly one.
How to take it
Saxenda is injected once daily under the skin of the abdomen, thigh, or upper arm. Dosing starts at 0.6 mg and rises weekly through 1.2, 1.8, and 2.4 mg to reach the 3 mg maintenance dose by week five. That escalation is faster than the weekly drugs.
Side effects
Nausea affected 39.3% of adults in trials. Other common side effects include vomiting, diarrhea, constipation, headache, dizziness, and injection site reactions. These are similar to the GLP-1 class overall and tend to ease over time.
Effectiveness
Adults on Saxenda 3 mg lost an average of 7.4% of body weight at 56 weeks, against 3.0% on placebo. Around 62.3% lost at least 5% of their weight and 33.9% lost at least 10%. That is roughly half the result of standard Wegovy and a third of Zepbound at maximum doses. Generic liraglutide has reached the market, which makes it worth discussing when cost or supply rules out the newer options.
Setmelanotide (Imcivree)
How it works
Imcivree targets a specific pathway in the brain that regulates hunger, one that only malfunctions when certain rare gene variants are present. It does not work for obesity without those genetic causes.
How to take it
It is a daily injection for adults and children aged six and older. Genetic testing confirming variants in the POMC, PCSK1, or LEPR genes, or a diagnosis of acquired hypothalamic obesity, is required before it can be prescribed.
Side effects
Common side effects include injection site reactions, skin darkening, nausea, and headache. Sexual side effects, including spontaneous erections, have also been reported.
Effectiveness
Results vary by the specific genetic condition being treated. Imcivree is outside the conversation for most patients, but it matters for families with early-onset severe obesity and relentless hunger that never responded to standard approaches.
Diabetes Injections Prescribed Off-Label for Weight Loss
Ozempic and Mounjaro contain the same drugs as Wegovy and Zepbound. Their labels cover type 2 diabetes rather than weight, so using either for weight loss alone is an off-label use.
Ozempic is semaglutide capped at 2 mg weekly, a ceiling set for blood sugar control. Adults with type 2 diabetes lost about 14 pounds at that dose over 40 weeks, well short of what Wegovy's higher doses produce.
Mounjaro is tirzepatide at the same 15 mg ceiling as Zepbound, so the weight results match. The difference is the label and, more practically, what insurance will pay for.
Off-label prescribing is legal and common, and it sometimes makes sense when a plan covers the diabetes version and refuses the weight version. Two consequences follow, and both deserve a conversation before you start. Your dose ceiling may be lower than the evidence supports, and insurance rarely covers either drug for weight loss without a diabetes diagnosis.
Injections Sold for Weight Loss That the FDA Has Not Approved
This group is where most of the money gets wasted. Each of these is marketed for weight loss, and none of them has FDA approval for it.
HCG Injections
HCG is a hormone from the placenta, approved as a prescription drug for female infertility and certain hormone treatments in men. The FDA states plainly that no HCG product is approved for weight loss and that HCG is not effective in treating obesity.
The FDA's own consumer guidance is blunt about why people think it works. HCG programs pair the injections with a 500-calorie diet, and the weight comes off because of the starvation, not the hormone.
Those very low-calorie diets carry real danger without medical supervision, including gallstone formation, electrolyte imbalance, and irregular heartbeat. The FDA has also received reports of serious harm from HCG injections used for weight loss, including pulmonary embolism, cardiac arrest, and death.
Lipotropic and B12 Shots
Lipotropic injections, often sold as MIC shots, combine methionine, inositol, and choline, sometimes with vitamin B12. Med spas market them as fat burners and metabolism boosters.
No FDA approval exists for any of these as a weight loss treatment, and no trial evidence supports the claim that they cause weight loss on their own. A B12 injection corrects a B12 deficiency, which is a real condition worth treating, but correcting it does not make you lose weight if you were not deficient.
Note that these injections are unrelated to prescription peptide therapy, which uses specific compounds for specific clinical goals under physician supervision. The distinction is whether a licensed physician prescribed it for a documented reason.
Botox Injections Into the Stomach Wall
Botox has been studied as an obesity treatment, delivered by endoscope into the stomach muscle under sedation rather than as a shot you give yourself. It is not FDA-approved for weight loss, and the effect wears off in about three months.
This one belongs in a different category from the rest since it is a procedure, not an injection you take home. Evidence for it remains limited compared with the approved drugs.
How Much Each Type of Weight Loss Injection Costs
Cash prices have dropped significantly since manufacturers opened direct-to-patient channels. Here is what each type costs per month without insurance, based on current manufacturer self-pay programs.
Two rules apply across all manufacturer programs. They are national rather than regional, so Southern California patients access them on the same terms as anyone else. And they are closed to anyone on Medicare, Medicaid, TRICARE, or VA benefits. Commercially insured patients who qualify for a manufacturer savings card can pay as little as $25 per fill. Medicare Part D beneficiaries can access Wegovy and Zepbound KwikPen for $50 per month through the Medicare GLP-1 Bridge program, which runs from July 1, 2026 through December 31, 2027.
How to Choose Between Types of Weight Loss Injections
The choice rarely comes down to which drug produced the biggest number in a trial. 5 factors decide it in practice.
- Your diagnoses. Type 2 diabetes, sleep apnea, heart disease, and fatty liver disease each point toward a specific drug, since several of these injections carry approvals for those conditions alongside weight.
- Your insurance. A plan that excludes weight-loss drugs changes the entire calculation, and it is worth checking before you get attached to a particular brand.
- Injection frequency. Weekly suits most people better than daily, which is one reason Saxenda has fallen behind.
- Side effect tolerance. Higher doses produce more weight loss and more nausea. Holding a lower dose longer often solves the problem better than switching drugs.
- What is actually driving your weight? An underactive thyroid, perimenopause, or low testosterone will not respond to a GLP-1.
Lab work should come before the prescription rather than after. A metabolic health assessment covering fasting glucose, HbA1c, insulin, thyroid function, and a lipid panel tells you which category you belong in. It also shows whether a GLP-1 is the right tool at all.
Frequently Asked Questions About Weight Loss Injections
Which type of weight loss injection works best?
Tirzepatide (Zepbound) produced the largest average result among approved injections, at 20.9% of body weight over 72 weeks. Wegovy HD follows closely at 20.7%, then standard Wegovy at 14.9% and Saxenda at 7.4%. The best one for you depends on your diagnoses, your coverage, and what you tolerate.
Can you inject these anywhere on your body?
The weekly and daily GLP-1 injections go under the skin of your abdomen, thigh, or upper arm. Rotate the site with each dose rather than using the same spot. The upper arm usually needs another person to do it.
Do weight loss injections work without diet changes?
Every trial behind these drugs included a reduced-calorie diet and increased activity, so the published results reflect medication plus lifestyle change rather than medication alone. Skipping the lifestyle side also raises your risk of losing muscle along with fat.
How long can you stay on a weight loss injection?
Plan on long-term treatment. Obesity behaves as a chronic condition, and the appetite effects of these drugs last only as long as the drug is in your system. Coming off works better as a planned step with your physician than an abrupt stop.
What happens if a weight loss injection does not work?
Bring it up if you have not lost at least 5% of your body weight after 12 to 16 weeks at the maximum dose you tolerate. Response varies, and some people do not respond to a given drug at all.
Getting Evaluated for Weight Loss Injections in Southern California
Sorting the approved injections from the marketed ones is the easy part. Matching one to your labs, your diagnoses, and your coverage takes a physician who reviews all three.
Unify Care's board-certified physicians handle that evaluation and manage treatment from the first dose through every adjustment. More than 500 families across Southern California use the practice's concierge medicine in Orange County model, with house calls reaching Los Angeles, Riverside, Palm Springs, San Bernardino, and San Diego. Reach out to the team to book a visit.
Sources
- U.S. Food and Drug Administration. Wegovy (semaglutide) Prescribing Information, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/215256s033lbl.pdf
- U.S. Food and Drug Administration. Zepbound (tirzepatide) Prescribing Information, revised January 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/217806s002lbl.pdf
- U.S. Food and Drug Administration. Saxenda (liraglutide) Prescribing Information, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/206321s025lbl.pdf
- U.S. Food and Drug Administration. Ozempic (semaglutide) Prescribing Information, revised October 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/209637s035,209637s037lbl.pdf
- U.S. Food and Drug Administration. Questions and Answers on HCG Products for Weight Loss. https://www.fda.gov/drugs/medication-health-fraud/questions-and-answers-hcg-products-weight-loss
- U.S. Food and Drug Administration. Avoid Dangerous HCG Diet Products. https://www.fda.gov/consumers/consumer-updates/avoid-dangerous-hcg-diet-products
- U.S. Food and Drug Administration. FDA Approves First Medication for Obstructive Sleep Apnea, December 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-first-medication-obstructive-sleep-apnea
- Novo Nordisk. Wegovy HD (semaglutide 7.2 mg) Approved in the US, Providing 20.7% Mean Weight Loss, March 2026. https://www.biospace.com/press-releases/novo-nordisk-a-s-wegovy-hd-semaglutide-7-2-mg-approved-in-the-us-providing-20-7-mean-weight-loss
- Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine, 2022. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
- Wilding JPH, et al. Weight Regain and Cardiometabolic Effects After Withdrawal of Semaglutide: The STEP 1 Trial Extension. Diabetes, Obesity and Metabolism, 2022. https://pubmed.ncbi.nlm.nih.gov/35441470/
- Obesity Medicine Association. Top Weight Loss Medications, August 2026. https://obesitymedicine.org/blog/weight-loss-medications
- NovoCare. Get Your GLP-1 Medications Delivered With NovoCare Pharmacy. https://www.novocare.com/pharmacy.html
- Eli Lilly. Zepbound Savings and Insurance Options. https://zepbound.lilly.com/savings
- Centers for Medicare & Medicaid Services. Medicare GLP-1 Bridge. https://www.cms.gov/medicare/coverage/prescription-drug-coverage/medicare-glp-1-bridge
