# Research Peptide Fundamentals — aminopeptides.co > aminopeptides.co covers repair and metabolic research peptides — BPC-157, retatrutide, and tesamorelin — summarized from peer-reviewed literature. A digest, not a vendor or clinic. A plain-English reading desk for the published science on BPC-157, retatrutide, and tesamorelin — what each was studied for, in which species, and what the evidence actually shows. ## The short version This desk covers three research peptides studied for **repair and metabolic function**: BPC-157, retatrutide, and tesamorelin. A *peptide* is a short chain of amino acids — the same building blocks as proteins, but smaller. Each of the three has been studied for a different aspect of that repair-and-metabolism arc: BPC-157 for tissue and gut healing in animal models, tesamorelin for reducing visceral (abdominal) fat via the growth-hormone axis, and retatrutide — the featured compound here — for metabolic obesity treatment via three incretin receptors simultaneously. The desk does one job: it states, in plain language with citations, what each peptide was tested on, in which species, and how far that evidence extends. Most evidence stops well short of broad human approval. Retatrutide remains investigational. Tesamorelin is FDA-approved only for a specific HIV condition. BPC-157 has no approval anywhere. None of this is a store, none of this is a clinic, and no dose is ever recommended here. ## What this desk covers The three compounds on this site each sit in a different part of the repair-and-metabolism landscape: - [**BPC-157**](/bpc-157) is a fifteen-amino-acid peptide derived from a protective protein in gastric juice. Its decades-long animal record centers on *angiogenesis* — growing new blood vessels into damaged tissue — and it has been studied in tendon, gut, muscle and nerve injury models [4][5]. Only a handful of small human pilot reports exist [2]. - [**Retatrutide**](/retatrutide) is the featured compound here: an investigational 39-amino-acid peptide that simultaneously activates the GIP, GLP-1, and glucagon receptors. Its Phase 2 obesity trial showed a mean 24.2% body-weight reduction at 48 weeks [9], and a Phase 2 substudy in metabolic liver disease showed 82.4% relative reduction in liver fat at 24 weeks [8]. It is not approved and remains in Phase 3 trials. - [**Tesamorelin**](/tesamorelin) is a synthetic analogue of the body's growth-hormone-releasing hormone. It is FDA-approved to reduce excess abdominal fat in adults with HIV-associated lipodystrophy [14]. Outside that indication, use is off-label and investigational. Its mechanism runs through the pituitary — stimulating the body's own pulsatile growth hormone release rather than supplying exogenous GH [17]. Read each compound's page for a full breakdown, or [compare these peptides](/compare) side by side. ## What are research peptides? Proteins — enzymes, structural scaffolds, signaling hormones — are long amino-acid chains folded into specific shapes. A *peptide* is a shorter chain of the same amino acids, sometimes only three or four links, sometimes a few dozen. Short chains can act as keys fitting specific receptor locks on cell surfaces, triggering targeted responses. A *research peptide* is one that has been synthesized and studied in the laboratory — in cell cultures, in animals, occasionally in early human trials — but has **not** been approved as a medicine for general use. The term signals a regulatory gap: whatever preclinical or trial data exist, dosing, long-term safety, and real-world effectiveness are usually not established at the level required for regulatory approval. This desk quotes study data exactly as the study stated it — species, sample size, and setting — and draws no line from those numbers to any personal recommendation. ## How this desk reads the literature aminopeptides.co is a cross-referenced literature digest. Each compound page cites numbered sources; all sources are collected in the shared [references list](/references). Where evidence is preclinical only, we say so. Where it is single-lab or unconfirmed, we say that too. Where a compound carries a specific approval, we note its scope and its limits. No author biographies and no credentials are invented. The goal is an accurate, austere map of what is known — so the gaps are as visible as the signal. --- An austere digest of published research — mechanism, species, and outcome, exactly as the literature reports them.