✓ Medically reviewed by  ·  Last reviewed: May 2026

Morgan Ellis

Pharmacy Researcher · 8 years experience

Pharmacy researcher with 8 years reviewing clinical drug information, generic formulation equivalence, and international pharmaceutical standards. Focuses on patient-facing accuracy in medication education.

Best Peptides for Fat Loss: 10 Compounds Compared — GLP-1, GH Fragment, and Mitochondrial Peptides

The peptide research literature on fat loss splits cleanly into three mechanism families. Incretin agonists activate the GLP-1, GIP, and/or glucagon receptors — suppressing appetite, slowing gastric emptying, and (in the case of glucagon-arm activators) directly increasing energy expenditure. Growth-hormone-axis peptides raise endogenous GH/IGF-1 to promote lipolysis and shift body composition toward lean mass. Mitochondrial-derived peptides (MOTS-c is the prototype) modulate fat oxidation and metabolic flexibility upstream of receptor pharmacology.

Of the 39 research peptides catalogued on the MedsBase peptide hub, 10 have documented fat-loss readouts in human or near-translational research. They are ranked below by weight-loss effect size as published in the most recent peer-reviewed trials and pre-prints.

How to use this hub

Each of the 10 picks below carries: mechanism class, comparator drug (where one exists), manufacturer / research-source flag, link to the product page, link to the dedicated research guide (where one is published), and a “pick for” line summarising the research scenario the compound fits best.

• Maximum effect size (most research interest): the triple/dual agonists — Retatrutide, Tirzepatide, Survodutide, Mazdutide.
• Most clinically validated: Semaglutide and Tirzepatide (their comparators Ozempic / Wegovy / Mounjaro / Zepbound are FDA-approved for obesity).
• Stacking research: Cagrilintide as the amylin partner; CJC+Ipamorelin as the GH-axis adjunct; HGH Fragment 176-191 as the lipolysis-selective fragment.
• Visceral-fat-specific: Tesamorelin (comparator drug Egrifta is FDA-approved for HIV-associated lipodystrophy — the only approved GHRH analogue for visceral fat reduction).
• Mechanism-novel / upstream: MOTS-c.

1. Retatrutide (Eli Lilly LY3437943 — GLP-1 + GIP + glucagon triple agonist)

Mechanism class: Triple incretin agonist · Research stage: Phase 3 (TRIUMPH program) · View product · Full mechanism guide · Research protocol guide

Retatrutide is the deepest-effect-size weight-loss peptide currently in late-stage development. Phase 2 readouts published in New England Journal of Medicine 2023 showed mean weight loss of -24.2% at 48 weeks at the 12 mg dose in adults with obesity without diabetes — roughly 50% deeper than semaglutide’s STEP-1 readout and 25% deeper than tirzepatide’s SURMOUNT-1. The third receptor arm (glucagon) is the differentiator: glucagon activation increases hepatic energy expenditure and may also improve hepatic steatosis. Phase 3 readouts are expected through 2025–2026.

Pick for: researchers studying the upper bound of incretin-class weight loss; protocols modelling progression beyond GLP-1/GIP dual agonism. See the Retatrutide vs Tirzepatide head-to-head for direct effect-size comparison.

2. Tirzepatide (Eli Lilly — GLP-1 + GIP dual agonist; comparator Mounjaro / Zepbound)

Mechanism class: Dual incretin agonist · Comparator drug: Mounjaro / Zepbound (FDA-approved 2022/2023) · View product

Tirzepatide established the dual-agonist class. SURMOUNT-1 (Phase 3) showed -22.5% mean weight loss at 72 weeks at the 15 mg dose in adults with obesity — the deepest readout for any FDA-approved obesity drug at the time of publication. The addition of GIP to GLP-1 agonism appears to deepen the appetite-suppression effect and may attenuate the GI side-effect profile compared with GLP-1 monoagonism. As the regulatory comparator drug is approved, tirzepatide is the most clinically validated dual-agonist peptide for fat-loss research.

Pick for: dual-agonist mechanism research; protocols where regulatory-precedent data is needed alongside the experimental compound. Background: Ozempic vs Mounjaro head-to-head.

3. Semaglutide (Novo Nordisk — GLP-1 monoagonist; comparator Ozempic / Wegovy / Rybelsus)

Mechanism class: GLP-1 monoagonist · Comparator drug: Ozempic (T2DM, FDA 2017) / Wegovy (obesity, FDA 2021) / Rybelsus (oral, FDA 2019) · View product

Semaglutide is the molecule that built the modern obesity-pharmacology market. STEP-1 (Phase 3) showed -14.9% mean weight loss at 68 weeks at the 2.4 mg weekly dose. The well-characterised effect on appetite, gastric emptying, and reward-circuit signalling has made semaglutide the comparator molecule against which every newer incretin is benchmarked. Its longer-duration acylated structure (vs older GLP-1 agonists) supports weekly dosing.

Pick for: baseline GLP-1 monoagonism research; the comparator arm in any dual/triple-agonist study design. See: Ozempic buying guide · Ozempic cost · Online sourcing.

4. Survodutide (Boehringer Ingelheim BI 456906 — GLP-1 + glucagon dual agonist)

Mechanism class: GLP-1 / glucagon dual agonist · Research stage: Phase 2/3 · View product

Survodutide adds the glucagon arm to GLP-1 agonism without the GIP component — a distinct architecture from tirzepatide and retatrutide. Phase 2 readouts in adults with obesity showed -18.7% mean weight loss at 46 weeks at the 4.8 mg weekly dose. The glucagon arm also produces a striking effect in metabolic-dysfunction-associated steatohepatitis (MASH): Phase 2 MASH-specific data showed substantially higher fibrosis-resolution rates than GLP-1 monoagonism alone. Researchers studying GLP-1/glucagon co-agonism — and specifically the hepatic-lipid axis — should treat survodutide as the reference compound.

Pick for: GLP-1/glucagon dual-agonist mechanism research; MASH/fatty-liver protocols where the glucagon arm is differentiating.

5. Mazdutide (Innovent Biologics / Eli Lilly IBI362 — GLP-1 + glucagon dual agonist)

Mechanism class: GLP-1 / glucagon dual agonist · Research stage: Phase 3 (DREAMS program, China) · View product

Mazdutide is the second GLP-1/glucagon dual agonist on this page, developed primarily in China through Innovent’s licensing agreement with Eli Lilly. Phase 2 readouts in Chinese adults with obesity showed -11.1% mean weight loss at 24 weeks at the 6 mg dose. Phase 3 data is approaching submission to NMPA (China) regulatory review. The molecule is structurally similar to oxyntomodulin (a naturally occurring proglucagon-derived peptide with co-agonist activity), and the development trajectory parallels survodutide. For researchers focused on the Chinese / Asian obesity-research landscape, mazdutide is the regulatory-pathway-leading dual agonist.

Pick for: dual GLP-1/glucagon research in Asian-population contexts; comparator to survodutide.

6. Cagrilintide (Novo Nordisk — long-acting amylin analogue; CagriSema stack with semaglutide)

Mechanism class: Amylin receptor agonist (calcitonin family) · Research stage: Phase 3 (REDEFINE program, in combination with semaglutide as “CagriSema”) · View product

Cagrilintide adds a distinct, complementary mechanism to GLP-1 agonism. Amylin is a pancreatic hormone co-secreted with insulin that promotes satiety by acting on hindbrain amylin receptors — a different signalling pathway from GLP-1’s hypothalamic/vagal action. The headline finding from the REDEFINE Phase 2 trial: cagrilintide 2.4 mg + semaglutide 2.4 mg (“CagriSema”) produced -15.7% mean weight loss at 32 weeks, compared with -8.1% for semaglutide alone — additive effect without proportional GI-side-effect amplification. CagriSema Phase 3 readouts are pending. Cagrilintide is rarely researched standalone; its primary research interest is as the stack partner.

Pick for: researchers modelling combination incretin + amylin pharmacology; protocols isolating the amylin-receptor contribution to weight loss.

7. Tesamorelin (Theratechnologies — GHRH analogue; comparator Egrifta)

Mechanism class: GHRH analogue (long-acting) · Comparator drug: Egrifta (FDA-approved 2010 for HIV-associated lipodystrophy) · View product

Tesamorelin is the only FDA-approved GHRH analogue and the only peptide on this page with a regulator-approved indication specifically for fat loss — visceral adipose tissue reduction in HIV-associated lipodystrophy. The phase-3 LIPO-2 trial showed mean visceral-adipose-tissue (VAT) reduction of -15.2% at 26 weeks via direct measurement on CT. The mechanism — pulsatile GHRH receptor stimulation raising endogenous GH and IGF-1 — produces visceral-fat-selective lipolysis without the appetite-suppression mechanism of incretins. The research applicability extends beyond HIV: tesamorelin is studied as a comparator/adjunct in non-HIV abdominal-obesity research and NAFLD/NASH protocols.

Pick for: visceral-fat-specific research; GHRH-axis pharmacology; the only peptide on this page with a comparator drug holding a fat-loss indication.

8. HGH Fragment 176-191 (lipolysis-selective C-terminal fragment of growth hormone)

Mechanism class: C-terminal GH fragment, lipolysis-selective · View product

HGH Fragment 176-191 represents one of the cleanest dissociations between GH’s metabolic effects and its growth-promoting effects in the research literature. The C-terminal 16-amino-acid fragment retains GH’s lipolytic activity (mediated through hormone-sensitive lipase activation in adipocytes) but lacks the anabolic / insulin-resistance / IGF-1-raising effects of the full-length molecule. The compound is studied for direct fat-mobilisation in research protocols where the lean-mass anabolism of full GH is undesirable (or where IGF-1 elevation needs to be avoided for safety reasons in the research model). Studied doses are substantially smaller than full-length GH protocols.

Pick for: isolated lipolytic-mechanism research; protocols where the anabolic GH/IGF-1 arm is not wanted; preclinical models of localised fat reduction.

9. CJC-1295 + Ipamorelin Stack (GHRH analogue + selective GHRP)

Mechanism class: Synergistic GHRH + GHRP pulse stack · CJC-1295 without DAC · Ipamorelin · Stack guide

This isn’t a single molecule but the classical research stack pairing two GH-axis mechanisms. CJC-1295 without DAC (Mod-GRF 1-29) binds the GHRH receptor on pituitary somatotrophs; Ipamorelin binds the GHS-R1a (ghrelin) receptor on the same cell type. Activated together, the two receptors produce a synergistic GH pulse larger than either compound alone — without the cortisol/prolactin elevation seen with older GHRPs (GHRP-2, GHRP-6, hexarelin). In fat-loss research, the stack is studied as a complement to incretin protocols: incretin handles appetite/satiety, the GH stack handles body-composition preservation (lean mass retention during caloric deficit). The 100 mcg + 100 mcg pre-sleep dosing pattern is the most-studied protocol.

Pick for: body-composition-preservation research alongside an incretin protocol; lean-mass studies during energy deficit.

10. MOTS-c (mitochondrial-derived peptide; 12S rRNA-encoded)

Mechanism class: Mitochondrial-derived peptide, AMPK activator · View product

MOTS-c is the most-studied member of the mitochondrial-derived peptide (MDP) class — a 16-amino-acid peptide encoded within the 12S rRNA gene of the mitochondrial genome. Mechanistically distinct from every other compound on this page: MOTS-c activates AMPK signalling in skeletal muscle and adipose tissue, promoting fat oxidation and insulin sensitisation upstream of incretin pharmacology. The fat-loss readouts are smaller in absolute terms than the incretin agonists, but the mechanism is novel and the compound is studied as a metabolic-flexibility primer or insulin-sensitisation adjunct. Particular research interest in age-related metabolic decline (MOTS-c levels fall with age) and exercise mimetics.

Pick for: mitochondrial-bioenergetics research; metabolic-flexibility protocols; insulin-sensitisation studies; ageing research where MOTS-c restoration is the hypothesis.

Comparison table

Stacking research: which combinations have published readouts

Combination research is where the deepest mechanistic insight lives. Four stacks are most-discussed in current literature:

• CagriSema (cagrilintide + semaglutide). Phase 3 in progress. The headline Phase 2 finding — additive weight loss without proportional GI-side-effect amplification — is the cleanest published evidence for combination incretin pharmacology beyond single-receptor agonism.
• Retatrutide standalone vs combination with cagrilintide. Pre-clinical research suggests the triple-agonist + amylin combination is the obvious next-generation question. No published human data yet.
• Incretin + GH axis (e.g. Tirzepatide + CJC/Ipamorelin). The hypothesis: incretin handles caloric deficit and appetite; GH axis handles lean-mass preservation during the deficit. No randomised trial data exists; this is an off-trial research-protocol pattern.
• HGH Fragment 176-191 + a GHRH analogue. Studied as a separation-of-mechanism design: the fragment provides lipolysis, the GHRH analogue provides the systemic GH/IGF-1 elevation in a controlled way. Niche but well-defined research scenario.

Frequently asked research questions

Which peptide on this list has the deepest published weight-loss readout?

Retatrutide at the 12 mg dose, with -24.2% mean weight loss at 48 weeks in the Phase 2 trial published in NEJM 2023. Tirzepatide is the closest at -22.5% in SURMOUNT-1 over a longer (72-week) timeframe. The dual-glucagon compounds (Survodutide -18.7%, Mazdutide -11.1%) sit between the dual-agonists and the GLP-1 monoagonist (Semaglutide -14.9%).

Is CagriSema better than Retatrutide?

Direct head-to-head data does not yet exist. Indirect comparison from Phase 2 readouts puts Retatrutide deeper at the matched 32–48-week window (-24.2% vs -15.7%). The CagriSema architecture is the leading “stacked” combination at this stage; Retatrutide is the leading single-molecule. Phase 3 readouts in 2025–2026 should clarify the comparison.

Where do the GH-axis peptides fit alongside the incretins?

They address a different mechanism. Incretin agonists drive weight loss primarily through appetite suppression, slowed gastric emptying, and (with the glucagon arm) modest direct energy-expenditure increase. GH-axis peptides (Tesamorelin, HGH Fragment, CJC+Ipamorelin) drive lipolysis and shift body composition toward lean mass. The classical research design uses incretin as the primary fat-loss driver and a GH-axis peptide as a lean-mass-preservation adjunct during caloric deficit. Tesamorelin specifically is the visceral-fat-selective option.

Why is MOTS-c on this list if its effect size is smallest?

Mechanism novelty. MOTS-c is the only mitochondrial-derived peptide with documented effects on metabolic flexibility, AMPK activation, and insulin sensitisation in human subjects. The fat-loss endpoints are smaller in absolute terms, but the upstream-mechanism research question is distinct from the incretin and GH-axis literatures and has unique applicability in ageing research.

Are these peptides interchangeable with the FDA-approved comparator drugs?

No. The compounds on this catalogue are research-grade lyophilized peptides for laboratory study. The FDA-approved comparator drugs (Ozempic, Wegovy, Mounjaro, Zepbound, Rybelsus, Egrifta) are finished pharmaceutical products with quality, fill-finish, labelling, and pharmacovigilance documentation specific to therapeutic use. The research-grade material is the same active molecule but is not the finished pharmaceutical product and is not approved for therapy.

What’s the difference between Tirzepatide and Retatrutide?

Receptor architecture. Tirzepatide activates GLP-1 + GIP (dual agonist). Retatrutide activates GLP-1 + GIP + glucagon (triple agonist). The glucagon arm adds direct hepatic energy expenditure and is the primary mechanistic differentiator. See the full comparison: Retatrutide vs Tirzepatide.

What’s the typical research dose of these incretin peptides?

Dose-finding ranges from published trials: Semaglutide 0.25 mg titrating to 2.4 mg weekly; Tirzepatide 2.5 mg titrating to 15 mg weekly; Retatrutide titrating to 12 mg weekly; Survodutide titrating to 4.8 mg weekly; Mazdutide titrating to 6 mg weekly. Cagrilintide is dosed at 2.4 mg weekly in the CagriSema combination. Tesamorelin is daily at 2 mg SC. All doses are research-protocol references; finished-drug labelling for the approved comparators may differ.

How should I think about reconstitution and storage for these compounds?

All lyophilized; reconstitute with bacteriostatic water before use; store the lyophilized vial at -20 °C long-term or 2-8 °C as working stock; store the reconstituted solution at 2-8 °C and use within ~30 days; protect from light; never freeze-thaw the reconstituted solution. The full reconstitution math with example calculations is at the BPC-157 reconstitution calculator and BAC water sterile-technique guide.

Bottom line

The incretin-class peptides (Retatrutide, Tirzepatide, Semaglutide, Survodutide, Mazdutide, with Cagrilintide as the amylin partner) define the upper bound of published weight-loss effect size and are the deepest-researched fat-loss compounds in modern pharmacology. The growth-hormone-axis peptides (Tesamorelin, HGH Fragment 176-191, CJC+Ipamorelin) handle a different mechanism — lipolysis and body-composition shift rather than appetite suppression — and are most relevant as adjuncts in fat-loss research designs. MOTS-c is the upstream mitochondrial outlier, useful for mechanism-novel research questions. For most fat-loss research, the strategic pick reduces to: incretin agonist as primary mechanism, GH-axis peptide as lean-mass-preservation adjunct if needed, mitochondrial peptide only for upstream-mechanism questions.

Written by

Sophie Chen

Pharmaceutical Content Researcher · 8 years experience

Sophie Chen is a pharmaceutical content researcher with 8 years covering generic medication access and clinical pharmacology. She specialises in international regulatory frameworks, bioequivalence standards, and patient-facing education on therapeutic drug classes. She is not a clinician.