Weight LossEvidence ReviewOct 2026

Peptides to Lose Weight: What Works and What Is Unproven

By Peptides Vietnam, published October 2026

Peptides to lose weight that are proven in people are approved prescription medicines: Wegovy (semaglutide), Zepbound (tirzepatide) and Saxenda (liraglutide). Research peptides sold online for fat loss, such as AOD-9604 and adipotide, have no randomized human weight-loss trial in our search. The approved medicines have FDA labels and large trials. For AOD-9604, the FDA says it has little safety information.

Sources: Zepbound (tirzepatide) FDA label, Eli Lilly, DailyMed; Wegovy (semaglutide) FDA label, Novo Nordisk, DailyMed; Saxenda (liraglutide) FDA label, Novo Nordisk, DailyMed; FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks

The short answer

What has strong human evidence?: Approved medicines with FDA labels for general weight reduction: semaglutide, tirzepatide and liraglutide. A newer approved pill, orforglipron, is not a peptide. Setmelanotide is another approved peptide, but only for rare genetic or brain-related obesity.
What is unproven?: Research peptides such as AOD-9604, adipotide, CJC-1295, ipamorelin and BPC-157. We found no randomized human weight-loss trial for any of them. Retatrutide has strong trial results but no approval.

This page describes what labels and studies report. It does not tell anyone what to take.

Which Peptides Have Been Approved by the FDA?

For general weight loss, three peptide medicines have FDA labels: Wegovy (semaglutide), Zepbound (tirzepatide) and Saxenda (liraglutide). The Foundayo pill is approved too, but it is not a peptide. One more peptide, setmelanotide (Imcivree), has an FDA label for long-term weight management, but only for a few rare genetic or brain-related causes of obesity, not for general weight loss.

The Saxenda and Foundayo labels pair the medicine with a reduced calorie diet and more physical activity.

The Wegovy label calls semaglutide a GLP-1 analogue with 94% sequence homology to human GLP-1. In plain words, it is built to look almost the same as a hormone the body already makes. The table below shows who each label covers.

Who each medicine is approved for, taken from the FDA labels on DailyMed. Columns: brand, ingredient and form, and who the label covers.
Brand	Ingredient and form	Who the FDA label covers
Wegovy	Semaglutide	Long-term weight reduction in adults, and in children 12 and older with obesity
Zepbound	Tirzepatide, injection	Adults with obesity, or overweight plus at least one weight-related health problem
Saxenda	Liraglutide, injection	Adults with obesity or overweight plus a weight-related health problem, and children 12 and older over 60 kg with obesity
Foundayo	Orforglipron, tablet (not a peptide)	Adults with obesity, or overweight plus at least one weight-related health problem
Imcivree	Setmelanotide, injection	Long-term weight management only in rare genetic or brain-related obesity (such as Bardet-Biedl syndrome or POMC, PCSK1 or LEPR deficiency), not general weight loss

For how these medicines are used and sold in Vietnam, see our weight loss hub. Each one also has its own profile, such as semaglutide, tirzepatide and liraglutide.

How Much Weight Did People Lose in the Trials?

In the main published trials, the biggest average weight change was -25.0% of body weight on 12 mg retatrutide in TRIUMPH-1. Liraglutide in the SCALE trial cut weight by 8.4 kg on average. Placebo groups lost much less in every trial.

These are averages across many people. Some lost more and some lost less.

The published trial papers in the New England Journal of Medicine report these average weight changes:

Average weight change in five trials, from the trial papers in the New England Journal of Medicine (STEP 1, SURMOUNT-1, SCALE, ATTAIN-1, TRIUMPH-1). Columns: trial, medicine, and reported result.
Trial	Medicine	Reported result
STEP 1	Semaglutide	-14.9% at week 68, against -2.4% with placebo
SURMOUNT-1	Tirzepatide	-15.0% with 5 mg weekly, -19.5% with 10 mg, and -20.9% in the third dose group, at week 72
SCALE	Liraglutide	8.4 kg lost on average at week 56, against 2.8 kg with placebo
ATTAIN-1	Orforglipron (pill)	-11.2% with 36 mg, against -2.1% with placebo
TRIUMPH-1	Retatrutide (not approved)	-17.6% with 4 mg, -23.7% with 9 mg, -25.0% with 12 mg, against -3.9% with placebo

Disclaimer: these are trial results and trial doses from supervised studies. They are not a recommendation or a promise of results. Dose decisions belong with a licensed clinician.

Trial length and design differ, so the rows are not a fair head to head race. For how these medicines and other peptides affect muscle as well as fat, see best peptides for muscle growth and fat loss.

Sources: STEP 1 semaglutide trial, N Engl J Med 2021, PMID 33567185; SURMOUNT-1 tirzepatide trial, N Engl J Med 2022, PMID 35658024; SCALE liraglutide trial, N Engl J Med 2015, PMID 26132939; ATTAIN-1 orforglipron trial, N Engl J Med 2025, PMID 40960239; TRIUMPH-1 retatrutide trial, N Engl J Med 2026, PMID 42814954

Is There a New Weight Loss Pill Available?

Yes. Foundayo (orforglipron) tablets now have an FDA label for long-term weight reduction. It is not a peptide, even though it works on the same GLP-1 target.

The ATTAIN-1 trial paper calls orforglipron a small-molecule, nonpeptide oral GLP-1 receptor agonist. It comes as a tablet, not a shot. The label covers adults with obesity, or adults with overweight plus at least one weight-related health problem. Read more on our orforglipron profile.

Sources: Foundayo (orforglipron) FDA label, Eli Lilly, DailyMed; ATTAIN-1 orforglipron trial, N Engl J Med 2025, PMID 40960239

Which Peptides Are Effective for Reducing Belly Fat?

Only one FDA label we found names belly fat: Egrifta SV (tesamorelin). It is approved to reduce excess abdominal fat in HIV-infected adults with lipodystrophy.

The same label says Egrifta SV is not indicated for weight loss management, because it has a weight neutral effect. So tesamorelin is studied for where fat sits, not for how much a person weighs. See the tesamorelin profile for more.

AOD-9604 is often sold as a belly fat peptide. The FDA says it has no, or only limited, safety information on it. It says it cannot tell whether AOD-9604 would cause harm in people, and that it has seen serious adverse events that may be linked to it. Our search found no randomized human weight-loss trial for it. More on the AOD-9604 profile.

Sources: Egrifta SV (tesamorelin) FDA label, Theratechnologies, DailyMed; FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks

Is Retatrutide Safe?

Retatrutide's safety is not established. The FDA says it is not part of any FDA-approved drug, has not been found safe and effective for any condition, and cannot be used in compounding under federal law.

Trials in people do exist. TRIUMPH-1 reported large average weight changes, shown in the trial table above. An earlier phase 2 trial found that heart rate went up with dose. That rise peaked at 24 weeks and then came down. We used trial summaries only. No FDA label with full safety tables exists yet.

For the full trial history, see the retatrutide profile.

Sources: FDA: FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss; TRIUMPH-1 retatrutide trial, N Engl J Med 2026, PMID 42814954; Retatrutide phase 2 trial, N Engl J Med 2023, PMID 37366315

What Is Adipotide, and Does It Work?

Adipotide is a lab-made peptide that has only been studied in animals for weight loss. No FDA approval or label was found, and no human results have been published.

The idea started in a 2004 lab study. Researchers used a method called in vivo phage display to find a short peptide code, CKGGRAKDC, that homes to blood vessels in white fat. They then joined a cell killing peptide to it, aimed at a protein called prohibitin on those vessels. In that study, this caused white fat to be destroyed. The authors wrote that this work may lead to drugs for obese patients, which means it was not yet a human treatment.

A 2011 study tested the full compound, named adipotide, in obese monkeys. This is animal data. Adipotide caused cell death in the blood vessels of white fat. The monkeys lost weight quickly and their insulin resistance improved. At the doses the team found worked best, the monkeys also had predictable changes in kidney function, which reversed.

Not everyone agreed on why the monkeys lost weight. A 2012 reply argued the loss may instead reflect a direct effect of adipotide on food consumption, meaning the animals simply ate less. A separate 2012 study in obese mice found that the cell killing peptide improved glucose tolerance, and that this did not depend on weight or food intake. This is also animal data.

One human trial was registered for a related prohibitin targeting peptide, named Prohibitin-TP01 in the record. It was for men with advanced prostate cancer and obesity. The record does not use the name adipotide, so we do not claim they are the same drug. The record says the drug is not FDA approved or commercially available, and was used for research only. The trial is listed as terminated at the investigator's request, with no results posted.

The ClinicalTrials.gov record for that first-in-man trial lists this starting dose in its design:

0.03 mg/kg as an injection under the skin, once a day for 28 days.

Disclaimer: this is a trial design from a registry record for cancer patients, not a dose for the public and not a recommendation. Dose decisions belong with a licensed clinician.

Why target fat tissue at all? Fat tissue is not only fat cells. It also holds blood vessel cells, immune cells and other cell types. Fat cells store fat when there is extra energy and release fatty acids during fasting. They also make hormones such as leptin that help regulate food intake and insulin sensitivity. That is why fat tissue is a research target, but a target is not proof of a treatment.

Sources: Reversal of obesity by targeted ablation of adipose tissue, Nat Med 2004, PMID 15133506; Adipotide in obese monkeys, Sci Transl Med 2011, PMID 22072637; Comment on the 2011 adipotide monkey study, 2012, PMID 22539771; Glucose tolerance with a fat vessel targeting peptide in obese mice, 2012, PMID 22733798; ClinicalTrials.gov NCT01262664, Prohibitin-TP01 first-in-man trial; Adipose Tissue: Physiology to Metabolic Dysfunction, Endotext, NCBI Bookshelf

Research Peptides Sold for Weight Loss

A product labeled "for research purposes" is not an approved medicine. The FDA says it has warned companies that sold these drugs illegally.

The products held semaglutide, tirzepatide, retatrutide, survodutide or mazdutide. They were falsely labeled "for research purposes" or "not for human consumption."

Peptides such as CJC-1295, ipamorelin and BPC-157 are also sold with fat loss claims. We searched PubMed, the FDA compounding lists and openFDA. We found no randomized human weight-loss trial for any of them.

The FDA labels and trials on this page apply to approved medicines made under FDA rules. They do not carry over to a research product with the same name.

Sources: FDA: FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss; FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks

Side Effects Listed on the Labels

Stomach problems are the most common. The Zepbound label lists these as its most common side effects, each in 5% of patients or more: nausea, diarrhea, vomiting, constipation, belly pain, indigestion, injection site reactions, tiredness, allergic-type (hypersensitivity) reactions, burping, hair loss and acid reflux (GERD).

The Wegovy label has a boxed warning. It says semaglutide caused thyroid C-cell tumors in rodents at exposures like those in people. It is not known whether Wegovy causes these tumors, including medullary thyroid carcinoma, in humans.

Sources: Zepbound (tirzepatide) FDA label, Eli Lilly, DailyMed; Wegovy (semaglutide) FDA label, Novo Nordisk, DailyMed

Evidence Level for Each Peptide

Here is every compound on this page in one table, ranked from the strongest human evidence to the weakest.

Evidence level for each compound, built from the FDA labels, FDA pages and studies cited on this page. Columns: compound, approval status, and best evidence for weight loss.
Compound	Approval status	Best evidence for weight loss
Semaglutide	FDA approved for weight loss (Wegovy)	Large randomized trial in people (STEP 1)
Tirzepatide	FDA approved for weight loss (Zepbound)	Large randomized trial in people (SURMOUNT-1)
Liraglutide	FDA approved for weight loss (Saxenda)	Large randomized trial in people (SCALE)
Orforglipron	FDA approved pill (Foundayo), not a peptide	Large randomized trial in people (ATTAIN-1)
Setmelanotide	FDA approved (Imcivree), but only for rare genetic or brain-related obesity	FDA label for long-term weight management in those rare conditions
Retatrutide	Not approved; the FDA says it has not been found safe and effective	Phase 2 and phase 3 trials in people, no label
Tesamorelin	FDA approved for belly fat in adults with HIV lipodystrophy only	Label says weight neutral, not for weight loss
AOD-9604	Not approved; the FDA says safety information is limited	Our search found no randomized human weight-loss trial
Adipotide	Not approved; no label found	Monkey and mouse studies; a related human trial was terminated
CJC-1295, ipamorelin, BPC-157	Not approved for weight loss	Our search found no randomized human weight-loss trial

Sources: Wegovy (semaglutide) FDA label, Novo Nordisk, DailyMed; Zepbound (tirzepatide) FDA label, Eli Lilly, DailyMed; Saxenda (liraglutide) FDA label, Novo Nordisk, DailyMed; Foundayo (orforglipron) FDA label, Eli Lilly, DailyMed; Imcivree (setmelanotide) FDA label, via DailyMed; FDA: FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss; Egrifta SV (tesamorelin) FDA label, Theratechnologies, DailyMed; FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks; Adipotide in obese monkeys, Sci Transl Med 2011, PMID 22072637; ClinicalTrials.gov NCT01262664, Prohibitin-TP01 first-in-man trial

What the Evidence Does Not Show

The evidence does not show that the research peptides sold online for fat loss, such as AOD-9604, CJC-1295, ipamorelin and BPC-157, cause fat loss in people. These are the main gaps.

That AOD-9604, CJC-1295, ipamorelin or BPC-157 cause fat loss in people. We found no randomized human trial for any of them.
That adipotide works or is safe in people. The data are from monkeys and mice, and the one related human trial was terminated.
That retatrutide is safe for general use. It has trial results but no FDA label.
That tesamorelin causes weight loss. Its label says it is weight neutral.
That trial averages will match any one person's result.

Common Questions

What is the best peptide to lose weight?+

There is no single best peptide for everyone. The options with the strongest human evidence are approved prescription medicines: Wegovy (semaglutide), Zepbound (tirzepatide) and Saxenda (liraglutide). Each has large randomized trials and an FDA label. Research peptides sold for fat loss, such as AOD-9604 and adipotide, have no randomized human weight-loss trial in our search. Whether any medicine fits a person is a decision for a licensed clinician.

Which peptides have been approved by the FDA?+

FDA labels for general weight reduction cover Wegovy (semaglutide), Zepbound (tirzepatide) and Saxenda (liraglutide). Foundayo (orforglipron) is also approved for weight reduction, but it is a small-molecule pill, not a peptide. Setmelanotide (Imcivree) is another approved peptide, but only for a few rare genetic or brain-related causes of obesity, not general weight loss. Tesamorelin (Egrifta SV) is approved only to reduce excess belly fat in adults with HIV lipodystrophy, and its label says it is not for weight loss.

Which peptides are effective for reducing belly fat?+

The only label we found that names belly fat is Egrifta SV (tesamorelin). It is approved to reduce excess abdominal fat in HIV-infected adults with lipodystrophy. The same label says it is not indicated for weight loss because it has a weight neutral effect. For AOD-9604, the FDA says it has little or no safety information and has seen serious adverse events that may be linked to it.

Is there a new weight loss pill available?+

Yes. Foundayo (orforglipron) tablets have an FDA label for long-term weight reduction in adults with obesity, or overweight plus a weight-related condition. Orforglipron is a small-molecule, nonpeptide GLP-1 receptor agonist. In the ATTAIN-1 trial, the 36 mg group had an average weight change of -11.2%, against -2.1% with placebo.

Is retatrutide safe?+

That is not yet established. The FDA says retatrutide is not part of any FDA-approved drug, has not been found safe and effective for any condition, and cannot be used in compounding under federal law. In an earlier phase 2 trial, heart rate rose with dose, peaked at 24 weeks and then fell. No FDA label exists for it.

What is adipotide?+

Adipotide is a lab-made peptidomimetic built to home to the blood vessels of white fat and kill cells there. In obese monkeys it caused rapid weight loss and better insulin resistance, along with reversible changes in kidney function. It has no FDA approval. A related prohibitin targeting peptide was tested in a first-in-human trial that was terminated, and no human results were found.

Are research peptides labeled for research use legal to sell for weight loss?+

The FDA says it has warned companies that illegally sold unapproved drugs containing semaglutide, tirzepatide, retatrutide, survodutide or mazdutide that were falsely labeled for research purposes or not for human consumption. A research-use label does not make a product an approved medicine.

Sources: Wegovy (semaglutide) FDA label, Novo Nordisk, DailyMed; Zepbound (tirzepatide) FDA label, Eli Lilly, DailyMed; Saxenda (liraglutide) FDA label, Novo Nordisk, DailyMed; Foundayo (orforglipron) FDA label, Eli Lilly, DailyMed; Imcivree (setmelanotide) FDA label, via DailyMed; Egrifta SV (tesamorelin) FDA label, Theratechnologies, DailyMed; ATTAIN-1 orforglipron trial, N Engl J Med 2025, PMID 40960239; FDA: FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss; FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks; Retatrutide phase 2 trial, N Engl J Med 2023, PMID 37366315; Adipotide in obese monkeys, Sci Transl Med 2011, PMID 22072637; ClinicalTrials.gov NCT01262664, Prohibitin-TP01 first-in-man trial

Disclaimer: this is general education, not medical advice and not a dosing recommendation.