Several once-weekly injections can promote weight loss, but doctors prescribe them for different purposes. You’ll need to consider your overall health, risk of other conditions, and cost in determining which is best for you.

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If you have overweight, obesity, or weight concerns, you may wonder about a newer type of weight loss medication. Glucagon-like peptide-1 (GLP-1) agonists are gaining significant media attention as celebrities and social media personalities popularize these injections.

But can GLP-1 agonists like Ozempic and Wegovy really help you lose weight? What about other types of injections?

Read on to learn about these injections, who can get them, whether or not they work, and how they work.

Are weight loss injections always through the stomach?

The abdomen is the most common injection site for GLP-1 agonists. Doctors recommend it since it’s easily accessible. But you can also use your:

  • upper arms
  • outer thighs
  • upper buttocks
  • hips
  • lower back

Semaglutide is a medication that mimics the role of hormones in your gut called incretins. It helps stimulate your pancreas to increase the amount of insulin you produce. Insulin is a hormone that tells your cells to absorb sugar from your blood and use it for energy.

Semaglutide also helps to decrease your appetite, which may lead to weight loss.

Semaglutide injections are available under the brand names Wegovy and Ozempic.

Wegovy

Wegovy is a once-weekly stomach injection approved by the Food and Drug Administration (FDA) in 2021. Doctors may prescribe it for weight loss in people with obesity, meaning they have a body mass index (BMI) of 30 or higher. Doctors may also prescribe it for people with a BMI of 27 or higher if they have at least one related comorbidity, like diabetes or hypertension.

(Note: BMI is a controversial and potentially biased number based on your weight-to-height ratio.)

A doctor will prescribe Wegovy in addition to lifestyle changes, including a reduced-calorie diet and increased physical activity.

Ozempic

Doctors prescribe Ozempic as a once-weekly injection for people with type 2 diabetes at risk of cardiovascular problems. It helps manage blood sugar levels and makes people feel less hungry. It may also help prevent stroke.

You don’t use Ozempic in place of insulin. It’s also not FDA approved for weight loss, although some doctors prescribe it off label for this purpose.

What’s the difference between Ozempic and Wegovy?

Wegovy and Ozempic both have semaglutide as their active ingredient. So what’s the difference?

The main physical difference is that they have different maximum doses per injection. Ozempic maxes out at 2 milligrams (mg), while the maximum for Wegovy is 2.4 mg.

Practically, the FDA has approved them for different purposes. Ozempic is approved to manage blood sugar and lower your risk of complications like heart disease and stroke. Wegovy is approved for weight management.

Like semaglutide, liraglutide (Saxenda) stimulates your pancreas to make insulin when blood sugar levels are high. It also suppresses appetite and slows digestion. You can use it to manage blood sugar and to promote weight loss.

Along with a diet and exercise plan, liraglutide can help promote weight loss in people ages 12 and older with overweight or obesity. It also helps them avoid regaining it.

A 2022 Belgian study looked at the effects of liraglutide in 115 people with a median BMI of 34.8. After 4 months, the group’s median body weight had decreased by 9.2%. A 2017 literature review also found that liraglutide was effective in helping people lose weight and had the added benefit of blood sugar management.

Liraglutide is also available under the brand name Victoza. But Victoza isn’t FDA approved to help with weight loss. It helps people 10 years and older manage type 2 diabetes.

Tirzepatide (Mounjaro) differs from other GLP-1 agonists in that it’s also a glucose-dependent insulinotropic polypeptide (GIP) agonist. This dual role allows it to be even more effective. Early studies showed some people losing more than 20% of their weight after 72 weeks (about 18 months).

The FDA has approved Mounjaro to help people with diabetes manage their blood sugar. Some doctors may prescribe it off label for weight loss when other methods don’t work. Further clinical trials have recently concluded, and the manufacturers expect FDA approval by late 2023.

You inject tirzepatide once a week. It can slow down your digestion, making you feel fuller for longer. Appetite suppression combined with diet and exercise can lead to weight loss.

Unlike the others, botulinum toxin (Botox) isn’t a GLP-1 agonist. It’s a strong neurotoxin made by the bacteria Clostridium botulinum.

People use Botox cosmetically and therapeutically to treat facial wrinkles, migraine, spastic disorders, and other medical conditions. It works by temporarily paralyzing muscles.

People with obesity sometimes use it to help promote weight loss. But research on its effectiveness has been mixed.

A 2017 review of six clinical trials concluded that Botox didn’t help people with obesity lose weight.

A 2022 review of trials found the opposite — that people with obesity did lose weight after Botox injections in certain conditions. For example, diet management was an important factor. But the researchers noted that the trials were all relatively small.

The only FDA-approved stomach injections to help with weight management are semaglutide (Wegovy) and liraglutide (Saxenda). Neither has been extensively studied in people who don’t have overweight or obesity.

A 2022 literature review found that Wegovy worked best for weight loss compared with placebo and other antidiabetic medications. People also had greater weight loss with Wegovy than with Saxenda.

Wegovy lowered the risk of death from heart attack in people with diabetes plus overweight or obesity. Nonfatal heart attack and nonfatal stroke rates also decreased in the study.

But that study didn’t include Mounjaro. Research from 2022 found that the low dose of tirzepatide (5 mg) was as effective as the 2-mg dose of semaglutide, but the higher doses (10 and 15 mg) were more effective.

But the comparison was indirect, as the two drugs weren’t studied head to head. Other researchers have identified a need for a direct comparison.

Side effects may differ depending on which injection you take.

In general, side effects of GLP-1 agonists include:

  • nausea
  • vomiting
  • diarrhea
  • dizziness
  • increased heart rate
  • headache
  • stomach upset
  • infection

There may also be an increased risk of thyroid cancer and medullary thyroid cancer, especially if you’ve used GLP-1 agonists for 1 to 3 years.

See a healthcare professional right away if:

  • You have severe abdominal pain.
  • You have an allergic reaction, such as swelling in your eyes, mouth, throat, face, ankles, feet, or legs.
  • You have problems breathing or swallowing.
  • You have a fever, jaundice, or clay-colored stools.

Botox injections are typically safe and without risk of serious side effects when used for weight loss. You may experience minor side effects like headaches. Rarely, people may have an allergic reaction.

Many things influence the price of weight loss injections, including your insurance plan. Some insurance companies won’t cover them unless prescribed for certain medical conditions. Since there are no generic versions yet, GLP-1 agonist injections can cost upward of $1,000 a month.

As of May 2023, costs for a typical monthly supply are as follows:

Talk with a doctor and your insurance providers to see what options you have. Your insurance plan may need to approve the use of the medication before treatment to ensure coverage. Some drug manufacturers may also offer a temporary savings program, depending on your insurance.

Newer stomach injection medications may work for weight loss in people who have overweight or obesity. As of May 2023, only two have FDA approval and research showing their effectiveness: semaglutide (Wegovy) and liraglutide (Saxenda). But a doctor may prescribe other options off label.

Keep in mind that these medications are approved for people with obesity or overweight. There isn’t much research on their effectiveness in people with a lower BMI.