For individuals seeking information about weight loss injections available from physicians, this article provides insights into different types of injections, such as fat-burning, metabolism-boosting, and appetite-suppressant injections. Weight loss injections can help you attain a slimmer body, which seemed impossible before.
The Evolving Landscape of Weight Loss Medications
The pharmacological treatment of obesity is a fast-changing landscape, and care providers must strive continuously to stay current. Before 2012, there were few weight loss medications approved by the FDA. In the 2020s, glucagon-like peptide-1 receptor agonists (GLP-1 receptor agonists) exploded in popularity and media attention. Next came a dual receptor agonist, Mounjaro, which is indicated for type 2 diabetes, and Zepbound, which is indicated for obesity. With a growing selection of weight loss medications available, patients may ask what the strongest or most effective weight loss prescription medication is, and which one is best for them. The answer is complicated, and newer is not always better.
Determining Candidacy and Setting Expectations
Determining whether someone is a candidate for weight loss medications begins with BMI. For each individual case, the doctor and patient should discuss the patient’s current health issues, other medications, and family medical history. The average weight loss varies from 5% to 21%, with some people losing more and some people losing less. Most people regain weight if AOMs are discontinued. While some weight loss medications are FDA-approved only for adults, some-including semaglutide and liraglutide-are approved for children 12 and older with a BMI >/= 95th percentile. Some weight loss medications have been on the market for many years, and new ones emerge frequently. It can be easy to overlook first-generation AOMs, but these may be appropriate for some patients, especially when cost is a factor.
Types of Weight Loss Injections
Modern innovations have led to the development of weight loss injections, generally considered safe and effective for most people. It is important to understand the different types of weight loss injections so you get the best results. Some weight loss injections are officially approved by the Food and Drug Administration (FDA) in the United States for weight loss, and others are not officially approved for this purpose but can still be used to help you lose weight.
GLP-1 Agonist Injections
GLP-1 injections are a type of GLP-1 agonist. GLP-1 is a naturally occurring hormone that helps control hunger and keep your appetite down. GLP-1 agonists bind themselves to GLP-1 receptors and mimic the natural GLP-1 hormone, which in turn helps the body feel fuller faster and stay satisfied longer.
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- Semaglutide (Wegovy, Ozempic): Wegovy is a brand name for semaglutide, a GLP-1 receptor agonist. It was FDA-approved in 2021. It is administered as an injection and approved for use in adults and children aged 12 years or more with obesity (BMI ≥30 for adults, BMI ≥ 95th percentile for age and sex for children) or some adults with excess weight (BMI ≥27) who also have weight-related medical problems. The dose must be increased gradually over 16 to 20 weeks to arrive at the 2.4 mg dosage. This progression can help to alleviate side effects, which include gastrointestinal symptoms, headache, dizziness, and fatigue. It is intended to be used indefinitely, in combination with a healthy diet and exercise. Ozempic may be a more familiar name to some patients. Ozempic is FDA-approved for people who have type 2 diabetes and are at risk of cardiovascular problems. In addition to reducing appetite, Ozempic regulates blood sugar levels. Ozempic is not FDA-approved for weight loss, but it can be used for this purpose. Lose and maintain a healthy weight with semaglutide (the same ingredient in Wegovy and Ozempic) at home.
- Liraglutide (Saxenda, Victoza): Liraglutide is a daily injectable medication that acts on hormones that send signals from the gut to the brain to make the patient feel full quicker and decrease hunger signals. Doses start at 0.6 mg to 3 mg a day. Some patients may lose 5-10% of body weight, especially with the higher dose of liraglutide. Liraglutide is also approved for Type 2 Diabetes, under the brand name Victoza. Saxenda can be used to help obese and overweight adults with at least one weight-related condition lose weight, as well as for weight loss in children ages 12 years and older who weigh more than 60 kg (about 132 pounds) and have obesity based on their age, height, and sex. Victoza is FDA-approved for the management of type 2 diabetes in people who are ten years and older. It is not FDA-approved for weight loss.
- Emerging GLP-1 Options: Lilly is developing at least two new options. The first, orforglipron, is an oral GLP-1 inhibitor that completed a Phase 3 clinical trial in early 2025. It could provide a welcome alternative for people who do not want injections. Phase 3 results expected soon. at 36 weeks.
Dual Receptor Agonist Injections
Tirzepatide injections are often thought to be similar to GLP-1. While true, tirzepatide injections are considered a dual receptor agonist of GLP-1 and GIP receptors, making these injections much more potent. Tirzepatide has been shown to be about 40% more powerful than GLP-1 injections, which can work well for people who need to lose lots of weight. Tirzepatide has shown remarkable effects on appetite regulation, as well as regulating blood glucose and reducing cholesterol levels.
- Tirzepatide (Mounjaro, Zepbound): Zepbound is approved to treat obesity in adults with a BMI of 30 or greater. It is both a GLP-1 and a GIP receptor agonist. Like semaglutide, it works by reducing appetite and is meant to be used in combination with diet and exercise to lose weight. Mounjaro is FDA-approved to help with blood sugar management in people with diabetes, but it can be used off-label for weight loss. Mounjaro works by slowing down the digestion process, which will help you feel full for longer periods of time. In the SURMOUNT-1 trial, adults with obesity or overweight (without diabetes) taking tirzepatide achieved up to 22.5% average body weight reduction at 72 weeks. Tirzepatide is a dual GIP and GLP-1 receptor agonist that suppresses appetite, improves satiety, and supports metabolic health. In addition to impressive weight loss, studies show improvements in cardiovascular risk factors and metabolic markers. In England, Mounjaro is also being rolled out in GP surgeries and community clinics. But it's only available for people who have a number of certain conditions caused by obesity.
Lipotropic Injections ("Skinny Shots")
Skinny shots contain a blend of nourishing vitamins and lipotropic compounds that help activate the breakdown of fat during metabolism in the body. These injections also contain a healthy combination of amino acids to increase energy and aid in the weight loss journey. Because skinny shots have a blend of B vitamins and other compounds, these injections offer additional benefits besides weight loss, such as helping to regulate mood, clearing mental fog, and boosting energy.
- Choline: Choline injections are a common component of lipotropic injections (a cocktail designed to burn fat). It helps move fat out of the liver, which supports fat metabolism and aids weight loss. Choline is a natural compound found in your body, so side effects are generally minimal. It’s a good option if you’re looking to boost your metabolism while also supporting liver health. Choline is a water-soluble vitamin that regulates energy levels and metabolism and prevents fatty acid deposits.
- Inositol (Vitamin B8): Inositol (also known as vitamin B8, even though it is not actually a vitamin) helps your body use cholesterol and fat and helps with waste removal by helping fat cells leave the liver.
- L-Carnitine: L-Carnitine plays a role in the transportation of fatty acids into cells where they can be burned for energy. This injection can enhance your ability to burn fat, especially when paired with exercise. It may also improve stamina during workouts. L-carnitine is a naturally-occurring amino acid that provides energy and improves the function of the brain, heart, and muscles.
- Methionine: Another key player in lipotropic injections, methionine helps break down fat in the liver, similar to choline. It’s also essential for the production of antioxidants, which can help protect the body during weight loss. Methionine is particularly useful for people with sluggish metabolisms or fatty liver. Methionine is an amino acid that protects the body from free radicals that cause cell damage. Methionine also breaks down and processes fats and supports digestion.
- Vitamin B6: Vitamin B6 is water-soluble and is found in a number of foods. It boosts metabolism, reduces cravings, and aids in muscle growth.
- Vitamin B12: Vitamin B12 increases metabolism, which boosts energy by stimulating your body to convert fat into energy.
Other Weight Loss Medications
- Phentermine: Phentermine is the oldest and most widely used weight loss medication. It was originally used as a short-term medication to jump-start weight loss, but now newer medical guidelines have added it to long-term therapy. Side effects include headache, overstimulation, high blood pressure, insomnia, rapid or irregular heart rate, and tremor.
- Phentermine-Topiramate (Qsymia): Topiramate can be combined with phentermine to decrease appetite and cravings. Adults with migraines and obesity are good candidates for this weight-loss medication. Some patients may lose an average of 5-10% of body weight. Daily doses with four strengths start at 3.75 mg/23 mg to 15 mg/92 mg. Side effects include abnormal sensations, dizziness, altered taste, insomnia, constipation, and dry mouth.
- Naltrexone-Bupropion (Contrave): Naltrexone-bupropion combines an opioid receptor antagonist with an antidepressant to affect the pleasure-reward areas of the brain and thereby decrease cravings and appetite. Start with a daily dose of one 8/90 mg tablet and gradually increase to four tablets a day. The most common side effects include nausea, constipation, headache, vomiting, dizziness, insomnia, dry mouth, and diarrhea.
- Orlistat (Xenical, Alli): Orlistat is a lipase inhibitor that comes in a capsule. Undigested fat is then passed through the body. Some patients may lose about 5% of their body weight. An over-the-counter formulation is available at 60 mg capsules with each fat-containing meal. The only over-the-counter medicine for weight loss currently approved by the FDA is Alli (orlistat).
- Setmelanotide: Setmelanotide is a melanocortin-4 receptor agonist indicated for chronic weight management in adult and pediatric patients six years and older, with obesity due to certain rare genetic disorders.
- Plenity: A medical device rather than a medication, Plenity was FDA-cleared in 2019 for people with a BMI of 25 to 40. It consists of a capsule that releases a biodegradable, super-absorbent hydrogel into the stomach. The gel helps to increase satiety, enabling the person to eat less.
Investigational Medications
- Retatrutide: The other, retatrutide, targets GLP-1, GIP, and glucagon. At this writing, it is in Phase 3 clinical trials. In Phase 2, participants lost up to 24.2% of body weight at 48 weeks.
- MariTide: Amgen is developing MariTide, a monoclonal antibody designed to increase GLP-1 receptor activity while reducing GIP receptor activity. The once-monthly injection entered Phase 3 clinical trials in March 2025.
Benefits of Weight Loss Injections
If you're a good candidate, injections can offer real results:
- Faster Weight Loss: Especially when combined with diet and activity
- Appetite Control: Helps curb cravings and manage portion sizes
- Improved Metabolism: Supports your body in burning calories more efficiently
- Better Blood Sugar Control: Especially important for those with insulin resistance
Potential Risks and Side Effects
Like any medication, weight loss injections come with side effects. The most common include:
- Nausea
- Vomiting
- Diarrhea or constipation
- Headaches
- Allergic reactions (rare)
You should not take liraglutide or tirzepatide if you have a history of or increased risk of thyroid cancer. MHRA has also warned that Mounjaro may lower the effectiveness of the contraceptive pill.
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Important Considerations
- Prescription Only: Weight loss injections are available by prescription only.
- Administration by Healthcare Professional: Healthcare professionals can administer weight loss injections for you. Having weight loss injections administered by a healthcare professional rather than self-administering the injections ensures that the correct dose is given safely each time. Having a physician administer your weight loss injections may make you feel more comfortable during the experience. It can be difficult to self-administer injections, but if a doctor does it for you, you do not need to worry about administering the injection incorrectly and injuring yourself.
- Age Restrictions: Different weight loss injections are approved for different purposes. Saxenda is approved for use by adults and children ages 12 years and older, and Victoza can be used by adults and children ages ten years and older. Monjaro, Ozempic, and Wegovy can only be prescribed for adults.
- Comprehensive Treatment Plan: FDA-approved anti-obesity medications (AOMs) are safe, evidence-based therapies that target specific physiology to improve the disease and are most effective when used as part of a comprehensive treatment plan. A treatment plan for obesity can comprise multiple forms of treatment, including medications, diet, exercise, and/or surgery. All weight loss medications work best in the context of a healthy eating plan and exercise.
- Long-Term Use: Some weight management medications are designed for short-term use and others for long-term use. Those approved by the FDA for long-term use include orlistat (Xenical, Alli), phentermine-topiramate (Qsymia), naltrexone-bupropion (Contrave), liraglutide (Saxenda), semaglutide (Wegovy, Ozempic), and tirzepatide (Zepbound, Mounjaro).
- Metabolic Adaptation: AOMs may counter the effects of metabolic adaptation and prevent weight regain. After weight reduction, the body metabolically adapts, often causing an increase in hunger hormones and a decrease in satiety hormones and resting metabolic rate, all of which can contribute to weight regain.
- Cost and Insurance Coverage: As with many medications, some weight loss drugs have been on the market longer, have generic alternatives, and tend to be more affordable. GLP-1s are notoriously costly. The Kaiser Family Foundation estimates the annual net price of Wegovy at $13,600. Insurance coverage varies and will affect many patients’ choices about going on weight loss medications.
- Counterfeit Medications: Some online healthcare providers claim to sell Ozempic, Wegovy, or Zepbound at reduced prices. However, the FDA warns against buying medications from any source other than a state-licensed pharmacy. In April 2025, they banned the sale of “counterfeit” semaglutide and tirzepatide. These medications are not made or packaged by the original manufacturers. Instead, they are compounded medications. Compounded versions of medications are made by compounding pharmacies, often to tailor a medication to specific patient needs, like an allergy to an inactive ingredient. Compounded medications are not FDA-approved.
Lifestyle Changes and Nutritional Considerations
Losing weight is tough-especially when lifestyle changes alone don’t get you the results you want. So, you'll need to make healthy lifestyle changes while taking them. Eating a balanced diet - if you're less hungry and eating less food, you need to make sure your diet still has enough of the protein, vitamins and minerals your body needs. Eat a good balance of fruits, vegetables, wholegrains, lean meat, fish, pulses, and low-fat dairy foods. Staying physically active - research shows that weight-loss injections can lead to a loss of muscle mass as well as fat. If you’re eating less food while taking these drugs, you may be at risk of poor nutrition. That’s why eating a healthy balanced diet is still important.
While no specific vitamin or supplement is considered a “treatment” for obesity or overweight, certain ones help support metabolic health. For example, studies suggest that calcium and vitamin D may play a role in regulating belly fat.
The Importance of Medical Supervision
Medically-supervised weight loss helps you stick to your treatment plan and reach your weight loss goals. With prescription medications, a healthcare professional can weigh all factors affecting the patient’s lifestyle and BMI and monitor progress and side effects.
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