Key takeaways:
There are currently four FDA-approved peptide medications for weight loss: Zepbound (tirzepatide), Wegovy (semaglutide injection and pill), and Saxenda (liraglutide).
Several newer peptides, such as retatrutide, survodutide, and VK2735, are still in clinical trials and show promising results.
Unregulated or “grey market” peptides sold online are not FDA approved and may carry safety and quality risks.
Peptides have become a buzzword in the weight-loss world, promoted everywhere from social media to boutique wellness clinics. While there are a handful that have been FDA approved, and a few more in development, many unregulated products marketed as easy fixes for weight loss are blurring the lines for patients.
Here we’ll review the four FDA-approved peptides for weight loss and a few still in clinical development, as well as how to distinguish these from “grey market” products.
Peptides and weight loss: A refresher
Peptides are short chains of amino acids that often act as chemical messengers. The most well-known peptides in the weight-loss arena are incretin glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). They play a key role in regulating appetite and blood glucose.
Newer medications are categorized as peptides because they closely resemble naturally occurring peptides. They enhance their natural signals, helping people eat less and lose weight more effectively. But only a few have earned FDA approval so far.
Most peptide medications are available as injections due to poor absorption when taken orally. Those that are available in pill form are formulated with sodium N-(8-[2-hydroxybenzoyl]amino) caprylate, which facilitates absorption across the gastric mucosa.
FDA-approved peptides for weight loss
Currently, only four peptide medications are FDA approved for weight loss. They have clinical data showing that they’re safe and effective when used as directed.
Keep in mind, the recently approved Foundayo (orforglipron), which is also an oral GLP-1 receptor agonist for weight loss, is not a peptide. It’s a small molecule medication.
Liraglutide (Saxenda)
Liraglutide (Saxenda) was the first GLP-1 receptor agonist approved for weight loss for adults and adolescents ages 12 and older. It’s injected once daily.
During a 56-week trial, people using Saxenda lost an average of 8% of their starting body weight with the highest dose.
Semaglutide injection (Wegovy)
Semaglutide (Wegovy) is a once-weekly injectable GLP-1 receptor agonist for adults and adolescents ages 12 and older. During clinical trials, participants lost an average of 15% of their starting body weight over 68 weeks with the 2.4 mg dose.
More recently, a higher-dose (7.2 mg) version of Wegovy (called Wegovy HD) was approved. During clinical trials, people receiving the 7.2 mg dose lost about 19% of their starting body weight at 72 weeks, on average.
Beyond weight loss, injectable semaglutide (as Ozempic) also treats Type 2 diabetes, and has proven cardiovascular, liver, and kidney benefits for certain people.
Semaglutide pill (Wegovy)
Semaglutide is also available as an oral medication for adults. It’s taken once daily, first thing in the morning on an empty stomach and 30 minutes before any other medications. During clinical trials, participants lost an average of about 14% of their starting body weight at 64 weeks.
Oral semaglutide is approved to treat Type 2 diabetes (as Rybelsus and now Ozempic pill) and to lower the risk of serious cardiovascular outcomes among certain people.
Tirzepatide (Zepbound)
Dual GLP-1/GIP agonist tirzepatide (Zepbound) is a once-weekly injection. During clinical trials, people using the highest tirzepatide dose (15 mg) lost an average of 21% of their starting body weight over 72 weeks.
Zepbound was the first medication approved to treat moderate-to-severe obstructive sleep apnea. And similar to semaglutide, it also treats Type 2 diabetes (as Mounjaro) and has a growing list of potential uses.
Weight-loss peptides comparison table
Medication | Administration / dosing | Weight-loss results from clinical trials | Additional indications |
|---|---|---|---|
Liraglutide (Saxenda) | Daily injection | Average of 8% over 56 weeks | n/a |
Semaglutide (Wegovy) 2.4 mg Wegovy HD 7.2 mg | Weekly injection | Average of 15% over 68 weeks about 19% over 72 weeks | MASH Reducing the risk of major cardiovascular events in adults with cardiovascular disease and either obesity or overweight |
Semaglutide (Wegovy pill) | Daily tablet | About 14% of their starting body weight at 64 weeks | Reducing the risk of major cardiovascular events in adults with cardiovascular disease and either obesity or overweight |
Tirzepatide (Zepbound) | Weekly injection | Average of 21% of their starting body over 72 weeks | Moderate-to-severe obstructive sleep apnea in adults with obesity |
Promising peptides in clinical trials
Several other peptides are currently being studied in clinical trials for weight loss. GLP-1 and GIP remain common targets. But researchers are also exploring other peptide hormones — such as glucagon and amylin — as potential pathways for future treatments.
Retatrutide
Retatrutide is a GLP-1/GIP/glucagon agonist that’s administered as a once-weekly injection. Glucagon helps boost energy expenditure and promote fat burning. It also typically raises blood sugar levels, but this effect is balanced by the blood sugar-lowering actions of GLP-1 and GIP.
Early retatrutide clinical trial results have been promising. After 48 weeks (11 months), participants receiving the medication lost up to 24% of their starting body weight. For reference, people in the tirzepatide trial had about 21% average weight loss over 72 weeks.
The retatrutide phase 3 trial for weight loss will conclude by mid-2026. Other clinical studies are also underway, including a head-to-head trial with tirzepatide for weight loss.
Additional indications in clinical studies include:
Metabolic dysfunction-associated steatohepatitis (MASH)
Knee osteoarthritis in people with obesity
Survodutide
Survodutide is an investigational dual-agonist (GLP-1/glucagon) peptide that’s also given as a once-weekly injection.
In early clinical trials, people using the highest survodutide dose lost about 19% their starting body weight over 46 weeks, on average.
In addition to weight loss, other investigational indications include:
The phase 3 weight-loss trials for people with and without diabetes have been completed, but results haven’t been released yet.
VK2735
VK2735 is a dual GLP-1/GIP receptor agonist being studied as both a weekly injection and a daily oral medication. Early results suggest rapid and meaningful weight loss.
With VK2735 injections, the average weight loss was almost 15% with the highest dose at 13 weeks. Weight loss with the highest dose of the pill form was about 12% over the same time frame.
VK2735 injections are currently being studied in phase 3 trials involving people with and without diabetes. Both studies are expected to be completed in 2027.
Eloralintide
Eloralintide is an investigational amylin mimetic peptide. It’s being studied as a once-weekly injection. Findings from early clinical trials showed an average weight loss of 20% with the highest dose at 48 weeks.
Phase 3 trials are currently ongoing to study Eloralintide as a weight-loss treatment for people with and without diabetes. The studies are expected to be completed in the next 2 to 4 years.
Be aware of ‘grey market’ peptides
“Grey market” peptides are products sold outside of the traditional healthcare system, typically online or through wellness clinics. These products are often marketed to consumers as quick fixes for weight loss, muscle building, or recovery.
It’s important to be aware of these products and know how to counsel patients about them. In advertisements, companies use familiar drug names like semaglutide, tirzepatide, or retatrutide. But it’s not always clear that these are “research-grade” peptides intended for laboratory use, and not for human treatment. This can leave people to manage their own dosage and use without clear guidance or reliable safety and efficacy data.
Patients may also be unaware that grey market peptides bypass standard manufacturing safeguards. It’s important to point out that their ingredients, strength, and sterility can vary. Some may be mislabeled, contaminated, or contain impurities from the manufacturing process. In some cases, these impurities can trigger unwanted immune responses.
What about compounded peptides?
It’s important to distinguish grey market peptides from compounded medications. Compounded peptides are made by licensed pharmacies that must follow specific quality standards and sourcing requirements.
But these pharmacies generally can’t replicate commercially available peptide medications unless there’s a medical need, such as a shortage. There are also certain peptides that the FDA currently does not allow for compounding due to safety risks, though this may change.
The bottom line
Some peptide-based medications, such as Wegovy (semaglutide), Zepbound (tirzepatide), and Saxenda (liraglutide), are FDA approved and have strong evidence supporting their use for weight loss. This area is still evolving, though, with other peptides in development showing promising results, and additional indications being evaluated.
At the same time, it’s important for clinicians and consumers to be aware of “grey market” peptides sold online or through unregulated sources. These pose health risks, due to quality concerns, lack of oversight, and limited safety data.
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