Weight-Loss & Metabolic Peptide Research

Incretin Receptor Agonism

Retatrutide is engineered to activate the GIP, GLP-1, and glucagon receptors simultaneously, extending the single- and dual-receptor incretin agonist research that preceded it. As a triple agonist, it is frequently referenced in literature examining whether engaging all three receptor pathways at once produces a more pronounced effect on energy expenditure, glycemic control, and body composition than single-target compounds.

Single- & Dual-Receptor Incretin Agonism

Semaglutide (a GLP-1 receptor agonist) and Tirzepatide (a dual GIP/GLP-1 receptor agonist) are the earlier compounds that established the incretin-agonist research base Retatrutide's triple-receptor mechanism builds on. Semaglutide is not part of KYIN Peptides' catalogue, while Tirzepatide is now available as a research-use compound — both are referenced constantly in comparative incretin-receptor literature alongside Retatrutide, see the full Semaglutide vs Tirzepatide vs Retatrutide comparison.

HGH-Fragment Lipolytic Research

AOD-9604 is a synthetic fragment of the C-terminus of human growth hormone (hGH 176-191), engineered to isolate HGH's lipolytic (fat-metabolizing) activity from its growth-promoting and insulin-desensitizing effects. It represents a different design approach from the receptor-agonist and mitochondrial-signaling compounds above: rather than activating a receptor pathway, it is a truncated fragment of an existing hormone. See its full research profile.

Clinical & Preclinical Trial Data

Retatrutide: The Phase 3 TRIUMPH-1 trial (2,339 adults with obesity or overweight and at least one weight-related condition, without type 2 diabetes) reported a mean weight loss of 28.3% at the 12mg dose over 80 weeks, with 45.3% of participants losing at least 30% of body weight — a threshold historically associated with bariatric surgery. A study extension in participants with baseline BMI ≥35 reached an average of 30.3% weight loss at 104 weeks. All three doses tested (4mg, 9mg, 12mg) met their primary and key secondary endpoints against placebo. Full peer-reviewed results are still pending publication, following the precedent set by retatrutide's Phase 2 obesity data published in the New England Journal of Medicine in 2023. See how it compares to Semaglutide and Tirzepatide. See its full research profile.

Semaglutide: The Phase 3 STEP-1 trial (Wilding et al., New England Journal of Medicine, 2021; 1,961 adults with obesity or overweight, without diabetes) found that semaglutide 2.4mg reduced body weight by a mean of 14.9% over 68 weeks, versus 2.4% for placebo, with 86% of participants losing at least 5% of body weight. Semaglutide is FDA-approved for chronic weight management (as Wegovy) and type 2 diabetes (as Ozempic).

Tirzepatide: The Phase 3 SURMOUNT-1 trial (Jastreboff et al., New England Journal of Medicine, 2022; 2,539 adults with obesity or overweight, without diabetes) reported 16.0–22.5% mean weight loss across the 5mg/10mg/15mg doses over 72 weeks. A later head-to-head trial (SURMOUNT-5) found tirzepatide outperformed semaglutide directly: 20.2% versus 13.7% mean weight loss at 72 weeks. Tirzepatide is FDA-approved for chronic weight management (as Zepbound) and type 2 diabetes (as Mounjaro).

Humanin: Evidence is exclusively preclinical. The foundational insulin-sensitivity study (Muzumdar et al., PLOS One, 2009; 92 male Sprague-Dawley rats) found that continuous intracerebroventricular infusion of humanin significantly improved whole-body insulin sensitivity via hypothalamic STAT3 signaling — blocking STAT3 eliminated the effect. Separately, humanin is studied for neuroprotection through direct binding and inhibition of the pro-apoptotic protein BAX. No completed human clinical trial of exogenous humanin exists for any indication, and human pharmacokinetics have not been established.

5-Amino-1MQ: All available data is preclinical. A 2014 genetic knockdown study (Kraus et al., Nature) established NNMT as an obesity-relevant target in mice, and a 2018 pharmacology study (Neelakantan et al., Biochemical Pharmacology, University of Texas Medical Branch) introduced 5-Amino-1MQ itself, showing it reduced body weight and white adipose mass in diet-induced obese mice without affecting food intake or lean mass. No human clinical trials have been conducted. See its full research profile or discovery history, or how it compares to MOTS-c.

AOD-9604: Development was more extensive than most research peptides — Metabolic Pharmaceuticals ran six human trials in over 900 participants — but ultimately unsuccessful. A 12-week Phase IIa trial (300 participants) showed a modest weight-loss edge over placebo (2.6kg versus 0.8kg), but the pivotal 24-week Phase IIb trial (536 participants) found no statistically significant difference from placebo, and the obesity development program was discontinued in 2007.

See the discovery history behind these peptides →

These compounds come up constantly in weight-loss and metabolic research literature but aren't part of our standard catalogue. AOD-9604, Humanin, and Cagrilintide can still be sourced for your order — get in touch for pricing and lead time. Semaglutide is a patented prescription pharmaceutical and is included for research context only; KYIN does not sell it in any form.