Peptides for weight loss are mostly copies or combinations of the hormones your gut and pancreas release around meals. Semaglutide, tirzepatide, retatrutide and cagrilintide act on GLP-1, GIP, glucagon or amylin receptors, and their largest trials measured average weight reductions of about 15% to 25%. A second group, AOD-9604, MOTS-c and 5-Amino-1MQ, rests mostly on animal and cell research. This guide compares all seven, including what the studies found in women.
At a glance
- Semaglutide acts on one receptor (GLP-1), tirzepatide on two (GIP and GLP-1) and retatrutide on three (GIP, GLP-1 and glucagon).
- Headline average changes: −14.9% (semaglutide), up to −20.9% (tirzepatide) and up to −25.0% (retatrutide).
- Cagrilintide works through amylin receptors and is studied mostly with semaglutide, as CagriSema.
- AOD-9604 failed its larger human trial; MOTS-c and 5-Amino-1MQ have animal and cell data only.
- Women were 67.5% to 74.1% of the two flagship obesity trials, and pooled tirzepatide data showed larger average reductions in women.
Research vials featured in this guide
- Semaglutide: 5, 10, 20 and 30 mg. View research vials
- Tirzepatide: 10, 15, 20, 30 and 60 mg. View research vials
- Retatrutide: 5, 10, 30, 50 and 60 mg. View research vials
- Cagrilintide: 5 and 10 mg. View research vials
- AOD-9604: 10 mg. View research vials
- MOTS-c: 10 and 40 mg. View research vials
- 5-Amino-1MQ: 10 and 50 mg. View research vials
Table of contents
- How do peptides for weight loss work?
- Weight loss peptides compared
- Semaglutide: the GLP-1 reference point
- Tirzepatide and retatrutide
- Cagrilintide and CagriSema
- AOD-9604, MOTS-c and 5-Amino-1MQ
- Side effects in trials
- What trials found in women
- Vials and shipping
- Frequently Asked Questions
- References
How do peptides for weight loss work?
After a meal, the gut releases hormones that signal the pancreas and brain. The best studied is GLP-1 (glucagon-like peptide-1), whose receptors are linked to insulin release, slower stomach emptying and appetite signaling. Natural GLP-1 is broken down quickly, so these research compounds are modified to last about a week (Lau et al., 2015: semaglutide design).
Newer compounds add GIP (glucose-dependent insulinotropic polypeptide), a second gut hormone; glucagon, which acts mostly on the liver; and amylin, another pancreatic hormone (Coskun et al., 2022: triple agonist discovery). A smaller group works elsewhere: a growth-hormone fragment (AOD-9604), a mitochondrial peptide (MOTS-c) and an enzyme blocker that is not a peptide (5-Amino-1MQ).
Weight loss peptides compared: mechanism, trial stage and results
| Compound | What it is | How it works | Furthest trial stage | Headline result | Source |
|---|---|---|---|---|---|
| Semaglutide | Lipidated GLP-1 analogue, 31 amino acids | GLP-1 receptor | Phase 3, plus heart and kidney trials | STEP 1: −14.9% vs −2.4% at 68 weeks | Wilding et al., 2021 |
| Tirzepatide | Lipidated peptide, 39 amino acids | GIP and GLP-1 receptors | Phase 3, including vs semaglutide | SURMOUNT-1: −15.0% to −20.9% vs −3.1% at 72 weeks | Jastreboff et al., 2022 |
| Retatrutide | Lipidated peptide, 39 amino acids | GIP, GLP-1 and glucagon receptors | Phase 3 (TRIUMPH, TRANSCEND) | TRIUMPH-1: −17.6% to −25.0% vs −3.9% at 80 weeks | NEJM, 2026: TRIUMPH-1 |
| Cagrilintide | Lipidated amylin analogue, 37 amino acids | Amylin and calcitonin receptors | Phase 2 alone; phase 3 as CagriSema | Alone: −6.0% to −10.8% vs −3.0% (26 weeks); CagriSema: −20.4% vs −3.0% (68 weeks) | Lau et al., 2021; Garvey et al., 2025 |
| AOD-9604 | Growth-hormone fragment, 16 residues | Fat metabolism; no GH-receptor binding in mice | Phase 2b oral trial; program stopped | Under 1 kg extra loss vs placebo, not significant | Metabolic Pharmaceuticals, 2007 |
| MOTS-c | Mitochondrial-derived peptide, 16 amino acids | AMPK energy sensor | Preclinical; human study recruiting | Mice resisted diet-induced obesity | Lee et al., 2015 |
| 5-Amino-1MQ | Small molecule, not a peptide | Blocks the NNMT enzyme | Preclinical (cells, mice) | Obese mice lost weight and white fat without eating less | Neelakantan et al., 2018 |
Trial lengths, populations and analysis methods differ, and some results come from sponsor releases, so read the table as a map, not a ranking.
Semaglutide: the GLP-1 reference point
Semaglutide is GLP-1 modified with two amino-acid swaps and a fatty-acid chain that binds the blood protein albumin, stretching its reported human half-life to about 165 hours (Lau et al., 2015: semaglutide design).
In STEP 1, 1,961 adults with overweight or obesity and no diabetes averaged −14.9% body weight at 68 weeks, compared with −2.4% on an inactive treatment (placebo) (Wilding et al., 2021: STEP 1).
Tirzepatide and retatrutide: adding more receptors
Tirzepatide activates GIP and GLP-1 receptors in one molecule (Coskun et al., 2018: tirzepatide discovery). In SURMOUNT-1, 2,539 adults without diabetes averaged −15.0%, −19.5% and −20.9% in three study groups at 72 weeks, against −3.1% with placebo (Jastreboff et al., 2022: SURMOUNT-1).
In SURMOUNT-5, an open-label head-to-head trial (participants knew their group) in 751 adults with obesity, weight changed by −20.2% with tirzepatide and −13.7% with semaglutide at 72 weeks, and waist size by −18.4 cm versus −13.0 cm (Aronne et al., 2025: SURMOUNT-5).
Retatrutide adds the glucagon receptor, linked to energy use (Coskun et al., 2022: retatrutide discovery). Its 48-week phase 2 trial in 338 adults reported −8.7% to −24.2% across study groups versus −2.1% with placebo (Jastreboff et al., 2023: retatrutide phase 2), and TRIUMPH-1 reached −25.0% in its highest group at 80 weeks (NEJM, 2026: TRIUMPH-1). For the online nickname, see what “GLP-3” means.
Cagrilintide and CagriSema: the amylin route
Cagrilintide is a long-acting, lipidated analogue of amylin, a pancreatic hormone, built to outlast the short-lived earlier analogue pramlintide (Kruse et al., 2021: cagrilintide design). It binds amylin and calcitonin receptors rather than the GLP-1 receptor.
On its own, in a 26-week phase 2 trial of 706 adults, cagrilintide produced −6.0% to −10.8% across study groups versus −3.0% with placebo, with more stomach and gut side effects (Lau et al., 2021: cagrilintide phase 2). Paired with semaglutide as CagriSema, REDEFINE 1 reported −20.4% versus −3.0% at 68 weeks (Garvey et al., 2025: REDEFINE 1).
A February 2026 sponsor announcement for REDEFINE 4 reported −20.2% for CagriSema versus −23.6% for tirzepatide at 84 weeks (Novo Nordisk, 2026: REDEFINE 4).
AOD-9604, MOTS-c and 5-Amino-1MQ: earlier-stage evidence
AOD-9604 is a 16-residue peptide modeled on the tail end of growth hormone. In obese mice it reduced weight gain and increased fat burning without binding the growth-hormone receptor (Heffernan et al., 2001: AOD-9604 in obese mice). Human results were negative: the developer’s 2007 announcement reported less than 1 kg of extra weight loss versus placebo at 12 or 24 weeks, and the obesity program was stopped (Metabolic Pharmaceuticals, 2007: OPTIONS trial).
MOTS-c is a 16-amino-acid peptide encoded in mitochondrial DNA. In cells it activated AMPK, the enzyme that senses low energy, and treated mice resisted diet-induced obesity (Lee et al., 2015: MOTS-c discovery). A placebo-controlled study of about 120 adults with prediabetes is listed as recruiting, with no results posted (ClinicalTrials.gov: NCT07505745).
5-Amino-1MQ is a small molecule, not a peptide. It blocks NNMT, an enzyme that diverts nicotinamide away from recycling into NAD+. Diet-induced obese male mice given the inhibitor lost body weight and white fat without eating less (Neelakantan et al., 2018: NNMT inhibitor in mice).
What side effects did weight-loss peptide trials report?
Gastrointestinal effects dominate: in STEP 1 they affected 74.2% of the semaglutide group versus 47.9% on placebo, and 4.5% versus 0.8% stopped because of them (Wilding et al., 2021: STEP 1). In SURMOUNT-1 they were mostly mild to moderate, and adverse events led 4.3% to 7.1% of tirzepatide participants to stop versus 2.6% on placebo (Jastreboff et al., 2022: SURMOUNT-1).
With retatrutide, heart rate rose in phase 2, peaking at week 24 before declining (Jastreboff et al., 2023: retatrutide phase 2). In TRIUMPH-4, nausea affected 38.1% to 43.2% of retatrutide participants versus 10.7% on placebo, and dysesthesia (unusual skin sensations) 8.8% to 20.9% versus 0.7% (Lilly, 2025: TRIUMPH-4). See our retatrutide side effects guide for the full tables.
What did weight-loss peptide trials find in women?
Women made up most of the flagship obesity trials: 74.1% of STEP 1 (STEP 1 participant characteristics), 67.5% of SURMOUNT-1 (Jastreboff et al., 2022: SURMOUNT-1 baseline) and 436 of 706 in cagrilintide phase 2 (EU Clinical Trials Register: cagrilintide phase 2). SELECT, the heart-outcome trial, had only 28% women (ACC, 2023: SELECT summary).
A post hoc analysis of four SURMOUNT trials (2,999 women and 1,678 men) found average reductions of up to 24.6% in women versus 18.1% in men, with nausea and vomiting numerically more common in women (García et al., 2024: tirzepatide results by sex). The retatrutide phase 2 trial enrolled 163 women among 338 adults, and its prespecified subgroup analysis found greater percentage weight reduction in women (Jastreboff et al., 2023: retatrutide phase 2).
In a Mayo Clinic records review of 106 postmenopausal women using semaglutide, the 16 on menopausal hormone therapy lost 16% of body weight at 12 months versus 12% for the 90 who were not (Hurtado et al., 2024: semaglutide and hormone therapy). It was small and retrospective.
On the tirzepatide label, blood levels of combined oral contraceptive hormones fell, an effect linked to slower stomach emptying, and animal studies found reduced fetal growth in rats and rabbits (Zepbound prescribing information). Early-stage female data come from animals: MOTS-c prevented weight gain and insulin resistance in mice without ovaries, a model of estrogen loss (Lu et al., 2019: MOTS-c in ovariectomized mice), and 5-Amino-1MQ raised grip strength by about 40% in aged female mice (Dimet-Wiley et al., 2024: aged female mice).
None of the main trials here measured polycystic ovary syndrome (PCOS), fertility or pregnancy as outcomes. Browse the peptides for women hub for more women-focused study notes.
Vial sizes, storage and US shipping
All seven come as freeze-dried (lyophilized) powder in sealed vials, with storage conditions on the label. Concentration is vial mass divided by solvent volume: the peptide calculator does the arithmetic, our guide on how to reconstitute peptides explains it, and many labs use bacteriostatic water as a preserved diluent.
Ellepeptides ships to addresses within the United States. Orders over $200 after coupon discounts (before taxes and shipping) ship free; otherwise standard shipping is $15.99 per order. Delivery options and payment methods are shown at checkout; see the shipping policy.
Frequently Asked Questions
Which peptide has produced the most weight loss in trials so far?
Retatrutide holds the highest average figure in these sources: −25.0% in the top study group of TRIUMPH-1 at 80 weeks, against −3.9% with placebo. Tirzepatide reached −20.9% at 72 weeks and semaglutide −14.9% at 68 weeks. With no direct retatrutide-versus-tirzepatide trial, treat cross-trial comparisons as approximate.
How is tirzepatide different from semaglutide?
Semaglutide acts on one receptor (GLP-1), while tirzepatide acts on two (GIP and GLP-1). In the head-to-head SURMOUNT-5 trial, 751 adults with obesity averaged −20.2% with tirzepatide and −13.7% with semaglutide at 72 weeks. The trial was open-label, so read the gap with that design in mind.
What side effects were reported in weight-loss peptide trials?
Gastrointestinal effects such as nausea were the most common. In STEP 1, 74.2% of the semaglutide group reported them versus 47.9% on placebo. In retatrutide’s TRIUMPH-4, nausea affected 38.1% to 43.2% versus 10.7%, and 12.2% to 18.2% stopped because of adverse events versus 4.0%.
Did women lose more weight than men in these studies?
In the analyses that checked, women averaged more. A post hoc look at four SURMOUNT trials found reductions of up to 24.6% in women versus up to 18.1% in men, and the retatrutide phase 2 subgroup analysis also favored women. These were secondary analyses, and the reason is still unknown.
Does AOD-9604 work for weight loss in human studies?
The larger human result was negative. The developer’s 2007 OPTIONS announcement reported less than 1 kg of extra weight loss versus placebo at 12 or 24 weeks, and the obesity program was stopped. The positive results come from rodent studies.
Is MOTS-c a weight-loss peptide?
Not yet in people. In mice, MOTS-c improved insulin sensitivity and prevented diet-induced obesity. The first placebo-controlled human study listed, MOTS-MET, plans about 120 adults with prediabetes over 12 weeks; check its registry record for results.
Is 5-Amino-1MQ a peptide?
No. It is a small molecule of about 159 g/mol as the cation, far smaller than any peptide, and it blocks the NNMT enzyme. Ellepeptides lists it with metabolic research compounds; its evidence comes from cells and mice only.
What is CagriSema, and how did it compare with tirzepatide?
CagriSema pairs cagrilintide with semaglutide. REDEFINE 1 reported −20.4% versus −3.0% with placebo at 68 weeks. In REDEFINE 4, a February 2026 sponsor report, it averaged −20.2% versus −23.6% for tirzepatide at 84 weeks. Ellepeptides lists cagrilintide on its own, not the combination.
Which vial sizes are available, and how does shipping work in the US?
Ellepeptides sizes range from a single 10 mg AOD-9604 vial to tirzepatide and retatrutide vials of up to 60 mg; the product box above lists each one. Orders ship to addresses within the United States, free over $200 after coupons, and delivery options are shown at checkout.
How should freeze-dried research peptides be stored?
Follow the vial label, which sets temperature and light conditions, and keep vials sealed and dry until needed. Let a chilled vial reach room temperature before opening so moisture does not condense on the powder. Once made up, 5 mg in 2.5 mL gives 2 mg/mL; record the lot number with each experiment.
References
- Lau et al. (2015). Semaglutide design and half-life. PubMed 26308095
- Wilding et al. (2021). STEP 1: semaglutide in adults with overweight or obesity. PubMed 33567185; PMC8089593
- ACC (2023). SELECT trial summary. acc.org
- Coskun et al. (2018). Tirzepatide (LY3298176) discovery study. PubMed 30473097
- Jastreboff et al. (2022). SURMOUNT-1: tirzepatide in obesity. PubMed 35658024; NEJM
- Aronne et al. (2025). SURMOUNT-5: tirzepatide vs semaglutide in obesity. PubMed 40353578
- García et al. (2024). Tirzepatide weight reduction by sex, SURMOUNT post hoc analysis (EASD 2024). EurekAlert news release
- Zepbound (tirzepatide) US prescribing information. DailyMed
- Coskun et al. (2022). Retatrutide (LY3437943) discovery study. PubMed 35985340
- Jastreboff et al. (2023). Retatrutide phase 2 trial in obesity. NEJM full text
- TRIUMPH-1 (2026). Retatrutide 80-week phase 3 trial. NEJM
- Lilly (2025). TRIUMPH-4 topline results. Lilly investor release
- Kruse et al. (2021). Cagrilintide design. PubMed 34288673
- Lau et al. (2021). Cagrilintide phase 2 weight trial. PubMed 34798060; EU register
- Garvey et al. (2025). REDEFINE 1: cagrilintide plus semaglutide. PubMed 40544433
- Novo Nordisk (2026). REDEFINE 4 topline results. Company announcement
- Heffernan et al. (2001). AOD9604 and fat oxidation in obese mice. PubMed 11673763
- Metabolic Pharmaceuticals (2007). Obesity drug phase 2b clinical trial results (OPTIONS). ASX announcement
- Lee et al. (2015). MOTS-c discovery study. PMC4350682
- Lu et al. (2019). MOTS-c in ovariectomized mice. PubMed 30725119
- ClinicalTrials.gov. MOTS-MET study record. NCT07505745
- Neelakantan et al. (2018). NNMT inhibitor, fat cells and obese mice. PMC5826726
- Dimet-Wiley et al. (2024). NNMT inhibition and exercise in aged female mice. PMC11226645
- Hurtado et al. (2024). Semaglutide in postmenopausal women with and without hormone therapy. PMC11209769
Explore the research catalog. Browse the full weight management collection, or go straight to semaglutide, tirzepatide, retatrutide, cagrilintide and AOD-9604 research vials. For laboratory research only. Not for human or veterinary use.
