# Metabolic & Weight Research research peptides — Zap Peptides > Zap Peptides is a reference desk for Metabolic & Weight Research research peptides — AOD-9604, tirzepatide, and MOTS-c — summarized from peer-reviewed literature with effect sizes and study designs. A digest, not a vendor or clinic. A data-forward reading desk for the published science on AOD-9604, tirzepatide, and MOTS-c — what each was tested on, in which species, and what the effect sizes actually showed. ## The short version Zap Peptides is a reading desk, not a store. It collects what the published research literature actually says about three molecules that appear repeatedly in conversations about **body recomposition and lipolysis**: AOD-9604, tirzepatide, and MOTS-c. A *peptide* is a short chain of amino acids — smaller than a full protein, often targeting a specific receptor or metabolic pathway. Each of these three was studied because it appears to interact with fat metabolism, energy use, or appetite signaling in some measurable way. This desk reports numbers as they appear in the source literature: species tested, sample sizes, effect sizes, and study design. That context matters. AOD-9604 produced fat loss in obese mice but did not beat placebo in human obesity trials [3][4][5]. Tirzepatide is FDA-approved with a Phase 3 dataset covering thousands of participants [11]. MOTS-c remains entirely preclinical, with human data limited to observational biomarker associations [14][15]. We do not sell anything, we do not give medical advice, and we never list a human dose. ## What are research peptides? A *peptide* is a chain of amino acids — the same building blocks as proteins, only shorter. Because of their compact size and structural specificity, peptides can bind to particular receptors or enzymes, modulating a pathway without engaging the whole signaling cascade of a larger hormone. A *research peptide* is one that has been synthesized and studied in laboratory settings — cell cultures, animal models, occasionally early human trials — but may not carry an approved therapeutic indication for human use. Within this desk, molecules span the full regulatory spectrum: tirzepatide is an FDA-approved prescription drug [9]; AOD-9604 is an investigational compound that failed its pivotal human obesity trial [3]; MOTS-c is a naturally occurring mitochondrial peptide studied as a research chemical [15]. Regulatory status, evidence depth, and species of origin are stated upfront for each, because those distinctions shape how any number from the literature should be read. ## How these three fit the metabolic frame The three peptides on this desk each target body composition from a different mechanistic angle. - [**AOD-9604**](/aod-9604) is the lead compound. A synthetic 16-amino-acid hexadecapeptide modelled on residues 177–191 of human growth hormone, it was engineered to replicate hGH's fat-metabolising C-terminal domain while avoiding growth-hormone-receptor binding. In obese mouse models it reduced body fat and increased beta-3 adrenergic receptor expression [4][5]; it did not produce statistically significant weight loss versus placebo in human trials [3]. WADA classifies it as S2-prohibited at all times in sport. - [**Tirzepatide**](/tirzepatide) is the most clinically established compound on this desk. A 39-amino-acid synthetic peptide that is the first dual GIP/GLP-1 receptor agonist, it is FDA-approved for type 2 diabetes and obesity. SURMOUNT-1 — a 2,539-participant Phase 3 RCT — recorded a mean weight change of −20.9% at the 15 mg dose versus −3.1% with placebo at 72 weeks [11]. SURMOUNT-5, a head-to-head against another incretin, recorded −20.2% versus −13.7% at 72 weeks [8]. - [**MOTS-c**](/mots-c) is the most experimental. A 16-amino-acid peptide encoded within the mitochondrial 12S rRNA gene, it activates AMPK by disrupting de novo purine biosynthesis and translocates to the nucleus under metabolic stress [17]. Exogenous administration significantly increased running capacity in aged mice [16]; human data consist of biomarker associations, not interventional outcomes [14]. [Compare these peptides](/compare) side by side on mechanism, evidence tier, and regulatory status. ## How this desk reads the literature Every claim on this site is attributed to a numbered citation from the shared [references list](/references). Where the evidence comes from an animal model, the species and sample size are stated. Where a human trial exists, the design (RCT, open-label, observational), participant count, and primary outcome measure are given. Where findings are inconsistent, contested, or drawn from a single lab, that is said plainly — evidence quality is part of the record, not buried in a footnote. This desk does not recommend, prescribe, or sell. No dose, protocol, or sourcing information appears anywhere on this site. The goal is a numerically honest map of what is known about each molecule — so that the signal-to-noise ratio is visible before any other conclusion is drawn. --- A numerically honest digest of the published evidence — effect sizes, study designs, and the gaps between them.