What are weight reduction injections, specifically referring to medications such as anti-obesity (weight loss) injections?

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From the Guidelines

Weight reduction injections are medications administered via injection to help people lose weight, with the most common types being GLP-1 receptor agonists like semaglutide (Wegovy, Ozempic) and tirzepatide (Mounjaro, Zepbound), which work by mimicking hormones that regulate appetite and blood sugar. These medications slow stomach emptying, increase feelings of fullness, and reduce hunger by acting on brain receptors. Some key points to consider when using weight reduction injections include:

  • Typical dosing starts low and increases gradually over weeks
  • Side effects commonly include nausea, vomiting, diarrhea, and constipation
  • These injections are typically prescribed for people with BMI ≥30 or BMI ≥27 with weight-related conditions like high blood pressure or diabetes
  • They're most effective when combined with diet and exercise changes
  • While these medications can produce significant weight loss (10-15% of body weight over a year), they generally require ongoing use to maintain results, as weight often returns when treatment stops 1.

It's also important to note that other medications, such as orlistat, phentermine, and lorcaserin, are available for weight loss, but may have different mechanisms of action and side effect profiles 1. Ultimately, the choice of medication and treatment plan should be individualized to each patient's unique needs and health status.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Definition of Weight Reduction Injections

Weight reduction injections refer to a type of medication administered via injection to help with weight loss. These injections typically contain a glucagon-like peptide-1 (GLP-1) receptor agonist, such as semaglutide, which has been shown to be effective in promoting weight loss and improving glycemic control in patients with or without type 2 diabetes 2, 3, 4, 5.

Mechanism of Action

The mechanism of action of weight reduction injections, such as semaglutide, involves activating the GLP-1 receptor, which helps to regulate appetite, satiety, and glucose metabolism. This leads to a reduction in body weight and improvements in cardiometabolic risk factors 3, 5.

Efficacy and Safety

Studies have demonstrated the efficacy and safety of weight reduction injections, such as semaglutide, in promoting weight loss and improving cardiovascular risk factors. For example, a study published in the New England Journal of Medicine found that semaglutide 2.4 mg once weekly resulted in a mean change in body weight from baseline to week 68 of -14.9% compared to -2.4% with placebo 3. Another study published in the Journal of Clinical Pharmacy and Therapeutics found that subcutaneous semaglutide 2.4 mg once weekly resulted in a dose-dependent reduction in body weight from baseline compared to placebo 4.

Common Adverse Events

Common adverse events associated with weight reduction injections, such as semaglutide, include gastrointestinal events such as nausea, diarrhea, and vomiting. These events are typically transient and mild-to-moderate in severity and subside with time 3, 4, 6.

Examples of Weight Reduction Injections

Examples of weight reduction injections include:

  • Semaglutide (Wegovy) 2.4 mg once weekly 2, 3, 4, 5
  • Liraglutide 3.0 mg daily 6
  • Tirzepatide once weekly 6
  • Combination of semaglutide and cagrilintide for weekly administration (currently in phase III development) 6
  • Oral semaglutide and non-peptide small molecule GLP-1 agonists for oral administration (currently in development) 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Wegovy (semaglutide): a new weight loss drug for chronic weight management.

Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 2022

Research

Once-Weekly Semaglutide in Adults with Overweight or Obesity.

The New England journal of medicine, 2021

Research

Clinical review of subcutaneous semaglutide for obesity.

Journal of clinical pharmacy and therapeutics, 2022

Research

Semaglutide for the treatment of obesity.

Trends in cardiovascular medicine, 2023

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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