Weight Loss Peptides: Everything You Need to Know

Peptide drugs are used to treat a variety of health conditions. Some may even help people who are overweight and obese lose weight and manage obesity-related conditions. Peptides for weight loss have gained popularity in recent years, showing promising results in clinical trials and real-world applications.

What are Peptides?

A peptide is a small chain of amino acids that makes up proteins in the body. Therapeutic peptides are developed to treat various health issues, including type 2 diabetes, HIV, and irritable bowel syndrome. Peptides are also a new tool doctors are prescribing to help people lose weight. Weight Loss Peptides: Everything You Need to Know

How Peptides Aid in Weight Loss

Here’s what you need to know about peptides for weight loss, which ones work best, and what side effects you may experience while using them. While the initial purpose of peptide drugs did not revolve around weight loss, researchers noticed that people did lose weight while using them.

In particular, glucagon-like peptide-1 (GLP-1) and its receptor agonists may help people lose weight. They stimulate the release of insulin, which improves blood sugar, so they’re often used to treat type 2 diabetes. Beyond that, they may reduce appetite and promote fullness. When people aren’t hungry and feel full, they may not eat as much. Over time, this may cause weight loss.

However, experts point out that peptides may not make everyone lose weight. More factors are at play, including diet and exercise habits, personal health history, and a person’s individual reaction to peptide drugs. Peptides can help promote weight loss by regulating the body’s natural appetite and fat-storage hormones, such as ghrelin and leptin. By normalizing these hormones, you can experience reduced hunger pangs that lead to decreased caloric intake and changes in metabolism that can support your weight-loss goals

Popular Peptide Drugs for Weight Loss

There are a number of peptide drugs that are marketed for weight loss. The following were recently identified by the Journal of Obesity & Metabolic Syndrome as the “next generation” of weight-loss medications.


The peptide drug of the moment is semaglutide. This GLP-1 receptor agonist is labeled to treat type 2 diabetes (brand name Ozempic) or obesity (brand name Wegovy). It’s approved by the Food and Drug Administration (FDA) and typically given via a once-weekly injection.

The effects of this drug seem to work well in the first year and may plateau around week 60 of treatment.


Liraglutide (brand name Saxenda) is another GLP-1 receptor agonist that is specifically approved for weight loss. Researchers explain that it reduces appetite and helps people keep weight off for at least a year. This medication is typically given in a once-daily injection.

It’s important to note that — while both semaglutide and liraglutide are “significantly” effective weight loss tools — experts believe semaglutide is a better value for the money than liraglutide.


Tirzepatide (brand name Mounjaro) is also a GLP-1 receptor agonist used to treat type 2 diabetes. In a study on over 2,500 adults, people who took varying doses of tirzepatide (ranging from 5 mg to 15 mg) experienced a “substantial and sustained” reduction in their weight over 72 weeks compared to those who received a placebo.

This drug is approved by the FDA to treat diabetes and can be used off-label to treat obesity. It’s typically given via a once-weekly injection.

Mechanism of Action of Weight Loss Peptides

GLP-1 Receptor Agonists

GLP-1 receptor agonists mimic the action of the GLP-1 hormone, which is released in the gut in response to food intake. These peptides help increase insulin secretion, decrease glucagon levels, and slow gastric emptying. This combination of effects helps reduce appetite and increase satiety, leading to reduced food intake and weight loss.

GIP Receptor Agonists

GIP (gastric inhibitory polypeptide) receptor agonists are another class of peptides being explored for weight loss. These peptides work by enhancing insulin secretion and modulating lipid metabolism. When combined with GLP-1 receptor agonists, they may have synergistic effects on weight loss and metabolic health.

Dual and Triple Agonists

Research is also focusing on dual and triple agonists that target multiple pathways involved in metabolism and appetite regulation. These peptides combine the effects of GLP-1, GIP, and other hormones like glucagon, offering a more comprehensive approach to weight loss and metabolic improvement.

Clinical Trials and Efficacy

Semaglutide Trials

Clinical trials have shown that semaglutide can lead to significant weight loss. In the STEP (Semaglutide Treatment Effect in People with obesity) trials, participants treated with semaglutide lost an average of 15-20% of their body weight over 68 weeks. These results highlight the potential of semaglutide as a powerful tool for weight management.

Liraglutide Trials

In clinical studies, liraglutide has also demonstrated substantial weight loss benefits. Participants taking liraglutide lost an average of 5-10% of their body weight over 56 weeks. The SCALE (Satiety and Clinical Adiposity—Liraglutide Evidence) trials underscored its effectiveness in long-term weight management.

Tirzepatide Trials

Tirzepatide has shown impressive results in clinical trials, with participants losing an average of 15-20% of their body weight over 72 weeks. The SURPASS trials highlighted its efficacy and safety, making it a promising candidate for obesity treatment.

Potential Side Effects

While peptide drugs offer promising results for weight loss, they are not without potential side effects. Common side effects of GLP-1 receptor agonists include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Headaches

These side effects are generally mild to moderate and tend to decrease over time as the body adjusts to the medication. However, it is important to consult with a healthcare provider to monitor for any adverse reactions and ensure the safe use of these medications.

Who Should Consider Weight Loss Peptides?

Weight loss peptides may be considered for individuals who have not achieved sufficient weight loss through diet and exercise alone, or for those with obesity-related health conditions such as type 2 diabetes, hypertension, or sleep apnea. It is essential to consult with a healthcare provider to determine if these medications are appropriate and to develop a comprehensive weight management plan that includes lifestyle changes.


Peptides represent a promising new avenue for weight loss and obesity management. With their ability to reduce appetite, improve satiety, and support metabolic health, they offer an effective tool for those struggling with weight loss. As research continues to advance, these medications may become an integral part of personalized weight management strategies.

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