Many people struggle with weight loss, and when diet and exercise aren't enough, weight loss injections can be an effective option. These injections, used in conjunction with a healthy lifestyle, can help individuals achieve their weight loss goals. This article provides an overview of different types of weight loss injections, how they work, and factors to consider when choosing the right treatment.
The Challenge of Weight Loss
Many people are left stumped for answers when it comes to weight loss. While eating fewer calories, moving your body, and getting appropriate sleep can sometimes bring success, what can you do if you don’t lose the pounds? It’s been deduced that more than 80% of Americans have a diet low in vegetables, dairy, and fruits. Similarly, a 2016 study found that only 2.7% of Americans met the requirements for a healthy lifestyle, which involved being sufficiently active, partaking in a nutritious diet, not smoking, and having a healthy fat body percentage. Many people may be unable to take the necessary steps for weight loss, whether due to a constantly changing routine or other lifestyle factors. Similarly, you may be doing everything right but failing to see the desired results. This is why weight loss injections have become popular among many people wishing to wear more conveniently sized garments. Fortunately, weight loss injections can be the answer to finally eliminate those tenacious pounds.
Types of Weight Loss Injections
Weight loss injections generally fall into the following categories:
GLP-1 Agonists: 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. Semaglutide and liraglutide work by targeting one gut hormone receptor. Semaglutide binds to GLP-1 receptors and stimulates insulin release from the pancreas when needed. It helps with weight loss by slowing down how fast food travels through your digestive tract (called gastric emptying). This may help you to feel fuller for a longer period of time and reduce how much food you consume.
Semaglutide: Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist. Ozempic and Wegovy both contain semaglutide. Ozempic is the brand name for Semaglutide, which originally was developed to help people struggling with type-2 diabetes manage their condition. With one weekly injection, Ozempic weight loss injections mimic the naturally occurring hormone GLP-1 (Glucogen-like peptide-1) which is what makes us feel full after eating - helping suppress your appetite and control cravings for effective weight loss. Ozempic also slows down the process of food leaving the stomach, meaning you’ll stay fuller for longer and be able to reduce the amount of calories you consume. 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.
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Wegovy is another weekly weight loss injection pen that works to suppress your appetite and control your cravings to help you shift excess weight. This medical weight loss treatment is much more personable, as there are a few different dosages to choose from (0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg) so you can select the one that will best help you meet your weight loss goals - adjusting this as and when you need to. 66% of patients have been able to lose 10% of their starting weight or more by using Wegovy injections in conjunction with a healthy diet and exercise routine that matches your lifestyle and fitness goals. 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.
Liraglutide: Saxenda is the brand name for a weight-loss injection called liraglutide. Saxenda weight loss injections work similarly to Ozempic and mimic the glucogen-like peptide hormone to regulate your hunger, but rather than a weekly injection, these weight loss injection pens need to be used daily. This is because it doesn’t last as long as Semaglutide (Ozempic) does, which is why it needs to be taken more often. Saxenda is one of the brand names for Liraglutide, which is also used as a medicine to help patients manage type-2 diabetes. 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. Side effects include nausea, diarrhea, constipation, vomiting, headache, decreased appetite, dyspepsia, fatigue, dizziness, abdominal pain, increased lipase, and renal insufficiency.
Dual Agonists (GIP and GLP-1): 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. Mounjaro and Zepbound both contain tirzepatide, a dual-acting GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist. GIP and GLP-1 are both natural incretin hormones.
Tirzepatide: Tirzepatide is a dual GIP and GLP-1 receptor agonist that suppresses appetite, improves satiety, and supports metabolic health.
Mounjaro: 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. Mounjaro lowers fasting and postprandial (after meals) glucose concentration, decreases food intake, and reduces body weight in patients with type 2 diabetes mellitus.
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Zepbound: In November 2023, Zepbound, the brand name for Eli Lilly's tirzepatide for weight loss, was approved by the FDA. 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.
Skinny Shots (MIC Injections): 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.
- Key components of skinny shots:
- Choline: Choline is a water-soluble vitamin that regulates energy levels and metabolism and prevents fatty acid deposits.
- Inositol: 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 is a naturally-occurring amino acid that provides energy and improves the function of the brain, heart, and muscles.
- Methionine: 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.
- Key components of skinny shots:
Comparison of Weight Loss Injections
It is safe to say each injection brings benefits that can help achieve weight loss goals. GLP-1 is popular among celebrities; tirzepatide has been deemed more potent than GLP-1 injections, and skinny shots can aid in weight loss but also help ensure you get a healthy dose of vitamins and their benefits.
Dosage and Administration
Mounjaro, Ozempic, Wegovy and Zepbound are all given weekly as a subcutaneous (under the skin) injection in the abdomen, thigh or upper arm. Products are available as injector pens and can be used by the patient or a caregiver at home, after instruction.
- Mounjaro (tirzepatide) injection single-use pens or vials are available in 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 and 15 mg doses. The recommended starting dosage is 2.5 mg subcutaneously once weekly, increasing to 5 mg once weekly after 4 weeks. If additional blood sugar control is needed, increase the dosage in 2.5 mg increments after at least 4 weeks on the current dose.
- Ozempic (semaglutide) injection pens deliver 0.25 mg, 0.5 mg, 1 mg, and 2 mg doses. The initial dose is 0.25 mg given subcutaneously once weekly (but is not used as an ongoing maintenance dose). After 4 weeks, the dose is increased to 0.5 mg once weekly. The maximum recommended dose of Ozempic for blood sugar control is 2 mg weekly. To reduce the risk of worsening kidney disease, kidney failure and cardiovascular death in adults with type 2 diabetes and chronic kidney disease, the recommended dose is 1 mg weekly, after an 8 week dose titration.
- Wegovy (semaglutide) injection single-dose pens are available in 0.25 mg, 0.5 mg, 1 mg, 1.7 mg and 2.4 mg doses. Start with 0.25 mg subcutaneously once weekly for 4 weeks. In 4 week intervals, increase the dose until a maintenance dose of 1.7 mg or 2.4 mg (recommended) is reached.
- Zepbound (tirzepatide) single-use pens deliver 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 and 15 mg doses. The recommended starting dosage is 2.5 mg subcutaneously once weekly, increasing to 5 mg once weekly after 4 weeks. The recommended maintenance dosages are 5 mg, 10 mg, or 15 mg injected subcutaneously once weekly.
Efficacy and Clinical Trial Results
- Zepbound: 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. Zepbound (tirzepatide) for chronic weight management (weight reduction and maintenance) was studied in 2 randomized, placebo-controlled, 72-week long, studies (SURMOUNT-1 and SURMOUNT-2) in over 3,400 adults with obesity or excess weight (overweight) and at least one weight-related condition. The average starting weight for study participants in SURMOUNT-1 was 105 kg (231 lb). At the highest dose (15 mg), people using Zepbound lost an average of 21.8 kg (48 lb) or 21% of their body weight, while at the lowest dose (5 mg), people lost an average of 15.5 kg (34 lb) or 15% of their body weight, compared to 3.2 kg (7 lb), or 3%, on placebo. The average starting weight for adult participants in SURMOUNT-2 was 101 kg (222 lb). For the primary endpoint, patients on Zepbound had a 47% greater relative weight loss compared to Wegoy (an average weight reduction of 20.2% with Zepbound compared to 13.7% with Wegovy). People using Zepbound lost on average 50.3 lbs (22.8 kg) vs. Secondary endpoints demonstrated at least a 15% weight loss in 64.6% of those in the Zepbound group compared to 40.1% on Wegovy. In addition, an average waist circumference reduction of 7.2 in (18.4 cm) was seen in the Zepbound group, compared to an average reduction of 5.1 in (13 cm) in the Wegovy group, a significant effect (P<0.001).
- Mounjaro: In Phase 3 studies in patients with type 2 diabetes, those treated with Mounjaro lost an average of 5.5 kg (12 lb) to 11 kg (25 lb) over 52-weeks. Approval was based on 40 to 52 week studies with over 6,200 participants in the Phase 3 SURPASS program. Participants achieved average A1C reductions between 1.8% and 2.4%.
- Wegovy: In the STEP Phase 3 studies, weight loss with Wegovy was assessed up to 68 weeks (104 weeks in STEP 5) in approximately 4,500 adults without type 2 diabetes taking Wegovy or an inactive placebo. STEP 2 did include those with type 2 diabetes. Groups also were counseled to follow a reduced-calorie diet and increased physical activity. The STEP 2 study also compared semaglutide 1 mg to semaglutide 2.4 mg for weight loss. As one study example, in STEP 1, the average starting weight for both groups was about 105 kg (232 lb). Over the 68-week period, adults in the group taking Wegovy lost significantly more weight than those taking an inactive placebo. With Wegovy, an average of 15.9 kg (35 lb), or about 15% of body weight, was seen. In addition, about 84% of people taking Wegovy lost 5% or more of their weight (vs. 31% of people on placebo); 66% lost 10% or more (vs. 12% on placebo), and 48% lost 15% or more (vs. Also, 77% of patients in the Wegovy group had a BMI reduction of at least 5% vs.
Important Considerations
Side Effects
Not everyone will have side effects from weight-loss injections. But it is very common for people who take them to experience digestive problems, such as feeling sick, diarrhoea, constipation and stomach pain. Speak to a GP or call 111 if you notice any symptoms, such as a sudden severe pain in the middle of your abdomen. Gastrointestinal (digestive tract) side effects are the most common side effects reported in at least 5% of patients with these medications. Nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion (dyspepsia), and stomach (abdominal) pain have been reported. After these medicines were approved by the FDA, ileus was reported as a possible side effect and updated in the product labels. An ileus (paralytic ileus) is an intestinal blockage that results in the failure of the intestinal contents to pass through the gut, but it doesn't involve a physical blockage. The FDA has received over 8,500 reports of gastrointestinal disorders after use of semaglutide medications (Ozempic, Wegovy), according to safety data they published through June 30, 2023. These side effects were reported voluntarily from a population of uncertain size.
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Contraindications
The labeling of these medicines carry a Boxed Warning for possible thyroid tumors, including cancer, which has been seen in animal studies. Do not use Ozempic, Mounjaro, Wegovy or Zepbound if you or anyone in your family has a history of medullary thyroid carcinoma (MTC), or if you have an endocrine system condition called Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). You should not take liraglutide or tirzepatide if you have a history of or increased risk of thyroid cancer.
Drug Interactions
MHRA has also warned that Mounjaro may lower the effectiveness of the contraceptive pill.
Importance of a Healthy Lifestyle
Weight-loss injections can be effective for weight loss. So, you'll need to make healthy lifestyle changes while taking them. 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. 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. Weight loss medications are nothing new, says Hong, and oral stimulant medications for weight loss have been in use since the 1960s. The difference with the latest weight loss injections is their effectiveness and easier use than older-generation injectables.
Cost and Availability
Right now, there are two main problems for patients when using the current injectable weight loss drugs: cost and side effects, Hong says. And in terms of cost, right now there’s been a manufacturing shortage as demand has skyrocketed for these drugs. “With any medication, the longer they have been on the market, sometimes the cost will come down a little bit,” he says. Additionally, many insurance companies won’t cover the cost of these drugs for weight loss alone, without the presence of diabetes or some other comorbid condition. Weight loss injections are available by prescription only, and 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. Medically-supervised weight loss helps you stick to your treatment plan and reach your weight loss goals.
Long-Term Weight Management
Another problem with current weight loss drugs is that people tend to regain weight if they stop taking the drugs, says Dr. Hong. Some drug makers are working to address this problem.
Which Weight Loss Injection Treatment Is Right for You?
No person is the same, which means no weight loss journey is the same either! If you are thinking about weight loss injections but aren’t sure which treatment is appropriate for you, speaking to a professional will help. Many factors go into choosing a weight loss injection treatment, such as how much weight you’d like to lose, physical activity, diet, and other issues (such as mental fog, poor sleep, etc.) that you’d like to address with these injections. At The Studio Med Spa, we make sure to connect patients with certified experts on our team who can provide the knowledge and guidance needed!
The Future of Weight Loss Medications
With fervent consumer demand for weight loss medications, combined with rising obesity rates, more medications are bound for the market in the coming years. Pharmaceutical platform Ozmosi predicts one to two GLP-1 launches annually starting in 2026. specifically for obesity. 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. 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. 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. Researchers continue to study hormones that play a role in appetite for other ways to target obesity with medication. Those of interest include not only GLP-1, but also peptide tyrosine-tyrosine (PYY) and cholecystokinin (CCK). With more options available, doctors will be increasingly able to personalize treatments.