Weigh loss injections

From W8MD weight loss and sleep centers

Weight loss injections, GLP-1 medications, incretin therapies, and emerging anti-obesity injections

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Weight loss injections
Weight loss injections
Injectable anti-obesity medications include GLP-1 receptor agonists, dual incretin agonists, and emerging peptide therapies
Specialty Obesity medicine, bariatric medicine, endocrinology, internal medicine, family medicine, sleep medicine
Uses Obesity, overweight, chronic weight management, type 2 diabetes, prediabetes, insulin resistance, obstructive sleep apnea, fatty liver disease, metabolic syndrome
Types Semaglutide, tirzepatide, liraglutide, retatrutide, CagriSema, cagrilintide, amycretin, exenatide






Related GLP-1 receptor agonist, GIP receptor agonist, amylin analog, medical weight loss, W8MD Weight Loss, Sleep and MedSpa
Weight loss injections such as GLP-1 receptor agonists can help selected patients achieve significant weight loss when combined with nutrition counseling, physical activity, and medical supervision.
W8MD Weight Loss, Sleep and MedSpa Centers provide physician-supervised medical weight loss, GLP-1 weight loss, sleep apnea care, and long-term weight maintenance.
Meal replacements, protein planning, and structured low-carbohydrate diet support can improve results during injectable weight-loss treatment.
File:Lose weight now.jpg
Modern anti-obesity medications target appetite, satiety, metabolism, and obesity-related disease rather than relying only on willpower.

Weight loss injections are injectable prescription or investigational medications used to help selected patients with obesity, overweight, type 2 diabetes, prediabetes, insulin resistance, sleep apnea, fatty liver disease, and other weight-related conditions. The most important modern category of weight loss injections includes GLP-1 receptor agonists and related incretin-based therapies, such as semaglutide, liraglutide, and tirzepatide. Newer investigational agents, including retatrutide, CagriSema, cagrilintide, and amycretin, are being studied because they may produce even greater weight loss or target additional appetite and metabolic pathways.

The term "weight loss injection" may refer to FDA-approved obesity medications such as Wegovy, Zepbound, and Saxenda, diabetes medications that may also cause weight loss such as Ozempic, Mounjaro, Victoza, Trulicity, Byetta, and Bydureon, or investigational drugs that are not yet FDA-approved for public use, such as retatrutide. Patients should avoid unapproved, counterfeit, "research-use," or do-it-yourself peptide injections.

W8MD Weight Loss, Sleep and MedSpa Centers can help patients choose the right weight loss injection by evaluating body mass index, waist circumference, medical history, type 2 diabetes status, sleep apnea symptoms, medication risks, insurance coverage, prior weight-loss attempts, nutrition needs, and long-term weight maintenance goals.

Overview

Modern injectable weight-loss medications have transformed obesity medicine. Older approaches often relied on short-term appetite suppressants or strict dieting alone. Newer incretin-based injections target the biology of appetite, satiety, gastric emptying, insulin secretion, glucagon, and blood glucose regulation. Many patients experience reduced hunger, earlier fullness, improved portion control, and substantial weight loss when these medications are used with a reduced-calorie diet, physical activity, and medical monitoring.

Injectable weight-loss medications may help patients with:

GLP-1 and incretin biology

Glucagon-like peptide-1, or GLP-1, is a hormone released from the gut after eating. GLP-1 helps regulate appetite and glucose metabolism. Drugs that mimic GLP-1 can increase fullness, reduce appetite, slow stomach emptying, improve insulin secretion, and reduce glucagon release.

Modern injectable therapies may target one or more of the following pathways:

Major types of weight loss injections

Medication or class Brand examples Status Main role
Semaglutide Wegovy, Ozempic Wegovy is FDA-approved for chronic weight management; Ozempic is FDA-approved for type 2 diabetes Weight loss, glucose control, cardiovascular risk reduction in selected patients
Tirzepatide Zepbound, Mounjaro Zepbound is FDA-approved for chronic weight management and moderate-to-severe obstructive sleep apnea in adults with obesity; Mounjaro is FDA-approved for type 2 diabetes Weight loss, glucose control, sleep apnea indication under Zepbound
Liraglutide Saxenda, Victoza Saxenda is FDA-approved for chronic weight management; Victoza is FDA-approved for type 2 diabetes Daily GLP-1 injection for weight management or diabetes
Exenatide Byetta, Bydureon FDA-approved for type 2 diabetes Diabetes treatment; may cause modest weight loss
Dulaglutide Trulicity FDA-approved for type 2 diabetes Diabetes treatment; may cause weight loss in some patients
Retatrutide Investigational Not FDA-approved as of 2026 Triple GIP/GLP-1/glucagon receptor agonist under study for obesity
CagriSema Investigational combination Not FDA-approved as of 2026 Combination of cagrilintide and semaglutide
Amycretin Investigational Not FDA-approved as of 2026 GLP-1 and amylin receptor agonist under study

FDA-approved weight loss injections

Semaglutide

Semaglutide is a once-weekly GLP-1 receptor agonist. It is marketed as Wegovy for chronic weight management and as Ozempic for type 2 diabetes. In the STEP 1 trial, semaglutide 2.4 mg once weekly plus lifestyle intervention produced a mean body weight reduction of 14.9% at 68 weeks, compared with 2.4% with placebo."Once-Weekly Semaglutide in Adults with Overweight or Obesity".New England Journal of Medicine.2021;384(11)

989-1002.doi:10.1056/NEJMoa2032183.PMID:33567185.

In 2024, the FDA approved Wegovy to reduce the risk of major adverse cardiovascular events in adults with established cardiovascular disease and either obesity or overweight.FDA Approves First Treatment to Reduce Risk of Serious Heart Problems Specifically in Adults with Obesity or Overweight(link). U.S. Food and Drug Administration.

Tirzepatide

Tirzepatide is a once-weekly dual GIP receptor and GLP-1 receptor agonist. It is marketed as Zepbound for chronic weight management and moderate-to-severe obstructive sleep apnea in adults with obesity, and as Mounjaro for type 2 diabetes.

The FDA approved Zepbound for chronic weight management in adults with obesity or overweight with at least one weight-related condition in 2023.FDA Approves New Medication for Chronic Weight Management(link). U.S. Food and Drug Administration. In 2024, the FDA approved Zepbound as the first medication for moderate-to-severe obstructive sleep apnea in adults with obesity, to be used with a reduced-calorie diet and increased physical activity.FDA Approves First Medication for Obstructive Sleep Apnea(link). U.S. Food and Drug Administration.

In the SURMOUNT-1 trial, adults with obesity or overweight treated with tirzepatide had average weight reductions of 19.5% and 20.9% with the 10 mg and 15 mg doses at 72 weeks."Tirzepatide Once Weekly for the Treatment of Obesity".New England Journal of Medicine.2022;387(3)

205-216.doi:10.1056/NEJMoa2206038.PMID:35658024.

Liraglutide

Liraglutide is a once-daily GLP-1 receptor agonist. It is marketed as Saxenda for chronic weight management and as Victoza for type 2 diabetes. Liraglutide was one of the earlier GLP-1-based obesity injections and helped establish incretin therapy as a major tool in obesity medicine.

In a randomized trial of liraglutide 3.0 mg for weight management, adults receiving liraglutide lost more weight than those receiving placebo."A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management".New England Journal of Medicine.2015;373(1)

11-22.doi:10.1056/NEJMoa1411892.PMID:26132939.

Diabetes injections that may also affect weight

Some injectable diabetes medications are not FDA-approved specifically for weight management but may help some patients lose weight as part of diabetes treatment.

Examples include:

These medications should be used according to their approved indications unless a qualified clinician determines that off-label use is medically appropriate.

Emerging weight loss injections

Retatrutide

Retatrutide is an investigational once-weekly triple hormone receptor agonist that activates the GIP receptor, GLP-1 receptor, and glucagon receptor. It is sometimes misspelled as Ritatrutide in online searches, but the correct drug name is Retatrutide.

Retatrutide is not FDA-approved as of 2026 and should not be purchased online, from peptide vendors, or from sources marketing it as "research use" for human injection. Eli Lilly describes retatrutide as investigational and notes that it is taken as a once-weekly subcutaneous injection in clinical trials.What to know about retatrutide(link). Eli Lilly and Company.

In a phase 2 trial published in the New England Journal of Medicine, once-weekly retatrutide produced substantial, dose-dependent weight reduction at 24 and 48 weeks, supporting further phase 3 investigation."Triple–Hormone-Receptor Agonist Retatrutide for Obesity".New England Journal of Medicine.2023;doi:10.1056/NEJMoa2301972.

CagriSema

CagriSema is an investigational combination of cagrilintide, an amylin analog, and semaglutide, a GLP-1 receptor agonist. The idea is to combine complementary pathways for appetite and body-weight regulation.

In 2025, a New England Journal of Medicine study reported that coadministered cagrilintide and semaglutide produced significant and clinically relevant body-weight reductions in adults with overweight or obesity compared with placebo."Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity".New England Journal of Medicine.2025;doi:10.1056/NEJMoa2502081.

Cagrilintide

Cagrilintide is an investigational long-acting amylin analog. Amylin is a hormone involved in satiety and post-meal glucose regulation. Cagrilintide is being studied alone and in combination with semaglutide.

Amycretin

Amycretin is an investigational therapy designed to activate GLP-1 receptor and amylin receptor pathways. Subcutaneous amycretin and oral amycretin are being studied in obesity and overweight. A 2025 Lancet publication investigated the safety, tolerability, pharmacokinetics, and effects on body weight of subcutaneous amycretin."Amycretin, a novel, unimolecular GLP-1 and amylin receptor agonist, for adults with overweight or obesity".Lancet.2025;doi:10.1016/S0140-6736(25)01185-7.

Other injectable or peptide-based therapies under study

Other emerging or investigational therapies may include:

These agents should be described as investigational unless they receive regulatory approval.

How weight loss injections work

Weight loss injections may work by:

Potential benefits beyond weight loss

Modern injectable obesity medications may provide benefits beyond weight reduction, depending on the medication and patient.

Potential benefits include:

Cardiovascular disease benefits

Weight loss injections may reduce cardiovascular risk factors such as obesity, blood pressure, glucose, and lipids. Additionally, Wegovy has an FDA-approved indication to reduce the risk of major adverse cardiovascular events in adults with established cardiovascular disease and obesity or overweight.FDA Approves First Treatment to Reduce Risk of Serious Heart Problems Specifically in Adults with Obesity or Overweight(link). U.S. Food and Drug Administration.

Sleep apnea benefits

Zepbound has an FDA-approved indication for moderate-to-severe obstructive sleep apnea in adults with obesity. This is a major development because it is the first medication approved for this indication.FDA Approves First Medication for Obstructive Sleep Apnea(link). U.S. Food and Drug Administration.

Patients with sleep apnea may still need CPAP, BiPAP, PAP therapy, dental appliances, or other sleep treatments. Weight loss injections should be integrated with sleep care rather than replacing sleep evaluation.

Fatty liver disease and inflammation

Obesity, insulin resistance, and type 2 diabetes are major risk factors for fatty liver disease and metabolic dysfunction-associated steatotic liver disease. Weight loss can reduce liver fat and improve metabolic risk. Some GLP-1 and incretin-based therapies are being studied for liver and inflammatory benefits, but patients with liver disease should receive medical monitoring.

Common side effects

The most common side effects of GLP-1 and incretin-based injections are gastrointestinal.

Common side effects may include:

Many side effects occur during dose escalation and may improve with time, smaller meals, hydration, and avoidance of greasy foods.

Serious risks and warnings

Potential serious risks may include:

  • Pancreatitis
  • Gallbladder disease
  • Severe dehydration
  • Kidney injury
  • Severe gastrointestinal disease
  • Low blood sugar when combined with insulin or sulfonylureas
  • Diabetic retinopathy complications in selected patients with diabetes
  • Serious allergic reaction
  • Thyroid C-cell tumor warning for some medications
  • Mood changes or suicidal thoughts in selected labeling

Patients should seek urgent medical care for severe abdominal pain, persistent vomiting, signs of dehydration, difficulty breathing, facial or throat swelling, severe rash, fainting, or symptoms of very low blood sugar.

Who may qualify for weight loss injections?

Eligibility depends on the medication, indication, body mass index, medical history, insurance rules, and clinician judgment.

Common criteria may include:

Who should avoid or use caution with weight loss injections?

Medical screening is essential. Some patients should avoid these medications or use them only with special monitoring.

Caution may be needed with:

Compounded and unapproved GLP-1 injections

Patients should be cautious with compounded or unapproved GLP-1 injections. The FDA has warned about fraudulent compounded semaglutide and tirzepatide products and broader concerns with unapproved GLP-1 drugs used for weight loss.FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss(link). U.S. Food and Drug Administration.

Patients should avoid:

  • "Research use only" peptides for human injection
  • Online retatrutide products
  • Fake semaglutide or tirzepatide
  • Unlicensed sellers
  • Products without pharmacy verification
  • DIY peptide mixing
  • Products claiming FDA approval when none exists
  • Medications without clinician oversight

Choosing the right weight loss injection

Choosing the right injection requires individualized medical judgment.

Important factors include:

  • Body mass index
  • Weight-loss goal
  • Type 2 diabetes status
  • Prediabetes status
  • Sleep apnea status
  • Cardiovascular disease history
  • Fatty liver risk
  • Prior medication response
  • Side effect tolerance
  • Pregnancy plans
  • Insurance coverage
  • Medication availability
  • Cost
  • Need for prior authorization
  • Preference for daily or weekly dosing
  • Need for long-term maintenance

How W8MD can help choose the right option

W8MD Weight Loss, Sleep and MedSpa Centers can help patients choose among weight loss injections and related therapies by providing physician-supervised evaluation and follow-up.

W8MD may help with:

Why W8MD may be a good choice

W8MD is not simply an injection clinic. W8MD integrates obesity medicine, sleep medicine, nutrition, medication management, and long-term follow-up.

Reasons patients may choose W8MD include:

  • Physician-supervised care
  • Experience with medical weight loss since 2011
  • Knowledge of GLP-1 and incretin medications
  • Multiple medication options
  • Meal replacement support
  • Low-carbohydrate diet support
  • Sleep apnea evaluation
  • Home sleep testing
  • CPAP support
  • Brooklyn and Philadelphia locations
  • Service to greater New York, New Jersey, Pennsylvania, Delaware, Connecticut, and nearby areas
  • Telemedicine when appropriate
  • Focus on long-term maintenance

W8MD and sleep apnea-focused weight loss injections

Because Zepbound is approved for moderate-to-severe obstructive sleep apnea in adults with obesity, W8MD’s combined weight loss and sleep medicine model is especially relevant. Patients may benefit from both medication-based weight reduction and direct sleep apnea treatment such as CPAP or PAP therapy.

Nutrition during weight loss injections

Weight loss injections reduce appetite, so nutrition quality becomes more important. Patients should avoid undereating protein or becoming dehydrated.

A good nutrition plan should include:

  • Adequate protein
  • Protein shakes if needed
  • Meal replacements when appropriate
  • Non-starchy vegetables
  • Fiber
  • Fluids
  • Electrolyte awareness
  • Reduced added sugar
  • Reduced refined carbohydrates
  • Smaller meals
  • Constipation prevention

Muscle preservation

Rapid or significant weight loss may include some loss of lean mass. To protect muscle, patients should focus on:

Frequently asked questions

What are weight loss injections?

Weight loss injections are injectable medications used to help selected patients lose weight by affecting appetite, satiety, glucose metabolism, or other hormone pathways.

Are GLP-1 injections the same as weight loss injections?

Many modern weight loss injections are GLP-1-based, but not all injectable weight-loss therapies are pure GLP-1 receptor agonists. Tirzepatide is a dual GIP/GLP-1 receptor agonist, and retatrutide is an investigational triple GIP/GLP-1/glucagon receptor agonist.

Which weight loss injections are FDA-approved?

FDA-approved chronic weight management injections include Wegovy, Zepbound, and Saxenda. Some diabetes injections such as Ozempic and Mounjaro may cause weight loss but are FDA-approved for diabetes indications.

Is Retatrutide FDA-approved?

No. Retatrutide is investigational and not FDA-approved as of 2026. Patients should not buy retatrutide online or inject products marketed as retatrutide.

Is Ritatrutide the same as Retatrutide?

"Ritatrutide" is a common misspelling. The correct name is Retatrutide.

Which is better, Semaglutide or Tirzepatide?

Both can be effective. Some studies show greater average weight loss with tirzepatide, but the best choice depends on medical history, goals, insurance, side effects, sleep apnea, diabetes status, and availability.

Can weight loss injections help sleep apnea?

Yes, in selected patients. Zepbound is FDA-approved for moderate-to-severe obstructive sleep apnea in adults with obesity, used with reduced-calorie diet and increased physical activity.

Can weight loss injections reduce heart disease risk?

Wegovy is FDA-approved to reduce major cardiovascular event risk in adults with established cardiovascular disease and obesity or overweight. Other weight loss injections may improve risk factors, but indications differ by medication.

Can W8MD help me choose between Wegovy, Zepbound, Saxenda, and other options?

Yes. W8MD clinicians can review medical history, weight goals, diabetes status, sleep apnea risk, insurance coverage, side effects, and preferences to help choose an appropriate option.

Do weight loss injections replace diet and exercise?

No. They work best with nutrition counseling, physical activity, protein planning, hydration, sleep care, and long-term maintenance.

When to call a doctor

Patients using weight loss injections should call a healthcare provider for:

  • Severe abdominal pain
  • Persistent vomiting
  • Severe constipation
  • Signs of dehydration
  • Symptoms of pancreatitis
  • Symptoms of gallbladder disease
  • Severe low blood sugar
  • New vision changes
  • Severe allergic reaction
  • Swelling of face, lips, tongue, or throat
  • Difficulty breathing
  • Mood changes
  • Pregnancy
  • Worsening sleep apnea symptoms

Summary

Weight loss injections, especially GLP-1 receptor agonists and related incretin therapies, have transformed medical weight loss. FDA-approved options include Wegovy, Zepbound, and Saxenda, while diabetes injections such as Ozempic and Mounjaro may also produce weight loss. Emerging medications such as retatrutide, CagriSema, cagrilintide, and amycretin may further change the field, but investigational products should not be used outside properly supervised clinical trials. W8MD Weight Loss, Sleep and MedSpa Centers can help patients select a safe, effective, individualized option while integrating nutrition, meal replacements, sleep apnea care, and long-term maintenance.

See also

Further reading

  • FDA Approves New Medication for Chronic Weight Management(link). U.S. Food and Drug Administration.
  • FDA Approves First Medication for Obstructive Sleep Apnea(link). U.S. Food and Drug Administration.
  • FDA Approves First Treatment to Reduce Risk of Serious Heart Problems Specifically in Adults with Obesity or Overweight(link). U.S. Food and Drug Administration.
  • FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss(link). U.S. Food and Drug Administration.
  • What to know about retatrutide(link). Eli Lilly and Company.
  • "Once-Weekly Semaglutide in Adults with Overweight or Obesity".New England Journal of Medicine.2021;384(11)
989-1002.doi:10.1056/NEJMoa2032183.PMID:33567185.
  • "Tirzepatide Once Weekly for the Treatment of Obesity".New England Journal of Medicine.2022;387(3)
205-216.doi:10.1056/NEJMoa2206038.PMID:35658024.
  • "A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management".New England Journal of Medicine.2015;373(1)
11-22.doi:10.1056/NEJMoa1411892.PMID:26132939.
  • "Triple–Hormone-Receptor Agonist Retatrutide for Obesity".New England Journal of Medicine.2023;doi:10.1056/NEJMoa2301972.
  • "Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity".New England Journal of Medicine.2025;doi:10.1056/NEJMoa2502081.
  • "Amycretin, a novel, unimolecular GLP-1 and amylin receptor agonist, for adults with overweight or obesity".Lancet.2025;doi:10.1016/S0140-6736(25)01185-7.

External links


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