Peptide guides
EDUCATIONAL ARTICLES28 GUIDES · 197 SECTIONSComprehensive peptide education — what they are, how they work, safety profiles, legal status, and research context.
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28
Guides
197
Sections
167
FAQs answered
106
Peptides referenced
Evidence-based educational content covering peptide science, safety, legal status, and research context. Sourced from peer-reviewed research and clinical literature.
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01What Are Peptides? A Complete Introduction8 SECTIONS→02How Do Peptides Work? Mechanisms Explained8 SECTIONS→03Are Peptides Safe? Risks, Side Effects & What the Research Says8 SECTIONS→04Peptides for Beginners: Where to Start8 SECTIONS→05Peptide Legal Status: What's Legal, Prescription, and Banned8 SECTIONS→06Peptide Safety Guide: Side Effects, Risks & Protocols8 SECTIONS→07How to Reconstitute Peptides: Dosing Math, Protocol & Storage7 SECTIONS→08Cardiovascular Peptides: A Guide to Antithrombotics, Natriuretic Peptides, and RAAS Peptides7 SECTIONS→09Gut Hormones: A Guide to Motilin, Secretin, PYY, GIP, Nesfatin-1, and Glucagon8 SECTIONS→10Antimicrobial Peptides: A Guide to Cathelicidins, Defensins, Magainin, and Clinical AMPs9 SECTIONS→11GnRH Analogs: A Guide to Agonists, Antagonists, and Clinical Uses7 SECTIONS→12Endogenous Opioid Peptides: A Guide to Dermorphin, Deltorphin, Kyotorphin, Nociceptin, and MIF-17 SECTIONS→13Thymic Peptides: A Guide to Thymopentin, Thymopoietin, Thymulin, and Thymus Extract7 SECTIONS→14Pain Peptides: A Guide to Substance P, Bradykinin, CGRP, Ziconotide, and Galanin7 SECTIONS→15Amylin Analogs: A Guide to Pramlintide, Cagrilintide, and the Amylin-GLP-1 Axis7 SECTIONS→16Collagen Peptide Types: Type I, II, III, and Hydrolysate Dipeptides Compared7 SECTIONS→17Peptide Therapeutics in Oncology: Proteasome Inhibitors, HDAC Inhibitors, and Beyond8 SECTIONS→18Somatostatin Analogs: A Guide to Somatostatin, Cortistatin, and SSTR Pharmacology6 SECTIONS→19Nootropic Peptides: Semax Variants, Selank, Dihexa, and Cerebrolysin Compared6 SECTIONS→20The Melanocortin System: α-MSH, NPY, Galanin, and Melanocortin-Receptor Pharmacology6 SECTIONS→21Reading a Peptide COA & Evaluating Supplier Quality9 SECTIONS→22GHK-Cu (Copper Peptide): Evidence, Mechanisms & Regulatory Status7 SECTIONS→23Retatrutide: Evidence, Mechanism & Trial Status7 SECTIONS→24Tirzepatide: Evidence, Mechanism & Approved Uses7 SECTIONS→25Semaglutide: Evidence, Mechanism & Approved Uses7 SECTIONS→26FDA Peptide Tracker 20263 SECTIONS→27Semaglutide vs Tirzepatide vs Retatrutide: 3-Way GLP-1 Comparison5 SECTIONS→28How PeptaHub Grades Peptide Evidence5 SECTIONS→Start here
01GUIDE
What Are Peptides? A Complete Introduction
Peptides are short chains of amino acids linked by peptide bonds, typically containing between 2 and 50 amino acids.
8 SECTIONS · 7 FAQRead →
02GUIDE
How Do Peptides Work? Mechanisms Explained
Peptides exert their biological effects by binding to specific receptors on or within cells, triggering signaling cascades that alter cellular behavior.
8 SECTIONS · 7 FAQRead →
03GUIDE
Are Peptides Safe? Risks, Side Effects & What the Research Says
The safety of peptides cannot be addressed with a single answer because peptides are an extraordinarily diverse class of molecules.
8 SECTIONS · 7 FAQRead →
All guides
28 ARTICLES
01
What Are Peptides? A Complete Introduction
The Basics: Amino Acids, Peptide Bonds, and Molecular Structure · Peptides vs. Proteins: What Is the Difference? · Natural Peptides: What the Body Already Produces
8 sections
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02
How Do Peptides Work? Mechanisms Explained
Receptor Binding: How Peptides Communicate with Cells · The GLP-1 Pathway: Appetite, Blood Sugar, and Beyond · The Growth Hormone Axis: Secretagogues and the Pituitary
8 sections
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03
Are Peptides Safe? Risks, Side Effects & What the Research Says
Understanding Evidence Levels: Clinical Trials vs. Animal Studies · FDA-Approved Peptide Drugs: Known Side Effects · Research Peptides: What We Know and What We Do Not Know
8 sections
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04
Peptides for Beginners: Where to Start
The Major Peptide Categories: A Map of the Landscape · How to Evaluate Evidence: The Beginner's Framework · Understanding Dosing: Basics for Beginners
8 sections
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05
Peptide Legal Status: What's Legal, Prescription, and Banned
The Regulatory Framework: How Peptides Are Classified · Category 1: FDA-Approved Peptide Drugs · Category 2: Compounding Pharmacy Peptides
8 sections
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06
Peptide Safety Guide: Side Effects, Risks & Protocols
General Safety Principles: The Framework Before the Details · Side Effects by Peptide Class: GLP-1 Receptor Agonists · Side Effects by Peptide Class: Growth Hormone Secretagogues
8 sections
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07
How to Reconstitute Peptides: Dosing Math, Protocol & Storage
Supplies You Need Before You Start · The Math: Concentrations, Units, and Dose Calculations · The Physical Reconstitution Procedure
7 sections
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08
Cardiovascular Peptides: A Guide to Antithrombotics, Natriuretic Peptides, and RAAS Peptides
Peptides in cardiovascular medicine: where they fit · Antithrombotics — direct thrombin inhibitors (bivalirudin) · Anti-platelet peptides — GPIIb/IIIa antagonists (eptifibatide, RGDS)
7 sections
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09
Gut Hormones: A Guide to Motilin, Secretin, PYY, GIP, Nesfatin-1, and Glucagon
Gut-brain axis intro — why gut hormones matter · Motilin — Phase III MMC contractions and the erythromycin connection · Secretin — the first hormone ever discovered (Bayliss & Starling, 1902)
8 sections
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10
Antimicrobial Peptides: A Guide to Cathelicidins, Defensins, Magainin, and Clinical AMPs
Why AMPs matter — the antimicrobial resistance crisis · Mechanism — membrane disruption and how AMPs kill bacteria · Cathelicidins and LL-37 (human AMP family)
9 sections
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11
GnRH Analogs: A Guide to Agonists, Antagonists, and Clinical Uses
GnRH biology — hypothalamic pulsatility and LH/FSH regulation · Agonists — flare then suppression (leuprolide, buserelin, histrelin, nafarelin, alarelin) · Antagonists — immediate suppression (cetrorelix, ganirelix)
7 sections
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12
Endogenous Opioid Peptides: A Guide to Dermorphin, Deltorphin, Kyotorphin, Nociceptin, and MIF-1
Opioid Receptor Primer: μ, δ, κ, and NOP · Dermorphin: A μ-Selective Heptapeptide From Frog Skin · Deltorphin: A δ-Selective Peptide From the Same Frog Family
7 sections
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13
Thymic Peptides: A Guide to Thymopentin, Thymopoietin, Thymulin, and Thymus Extract
Thymic Biology: T-Cell Maturation and Immunosenescence · Thymopoietin: The 49-Amino-Acid Parent Protein · Thymopentin (TP-5): The Five-Amino-Acid Active Fragment
7 sections
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14
Pain Peptides: A Guide to Substance P, Bradykinin, CGRP, Ziconotide, and Galanin
Peptides in Pain Pathways: Nociceptors to Supraspinal Modulation · Substance P and the NK1 Receptor · Bradykinin and the B2 Receptor
7 sections
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15
Amylin Analogs: A Guide to Pramlintide, Cagrilintide, and the Amylin-GLP-1 Axis
Amylin Biology: A Second Beta-Cell Hormone · Pramlintide (Symlin): The First Amylin Analog · Cagrilintide: A Long-Acting Weekly Amylin Analog
7 sections
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16
Collagen Peptide Types: Type I, II, III, and Hydrolysate Dipeptides Compared
Collagen Types Primer: 28 Types Known, 3 That Matter Most · Type I — Skin, Bone, Tendon: The Structural Collagen · Type II — Articular Cartilage and the Undenatured UC-II Mechanism
7 sections
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17
Peptide Therapeutics in Oncology: Proteasome Inhibitors, HDAC Inhibitors, and Beyond
Peptide Therapeutics in Oncology: Where Peptides Fit · Proteasome Inhibitors: Bortezomib and Carfilzomib for Multiple Myeloma · HDAC Inhibitors: Romidepsin for Cutaneous T-Cell Lymphoma
8 sections
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18
Somatostatin Analogs: A Guide to Somatostatin, Cortistatin, and SSTR Pharmacology
Somatostatin Biology: Hypothalamic Inhibitory Hormone · SSTR1-5 Receptor Subtypes and Tissue Distribution · Cortistatin: Structural Homolog with Distinct Biology
6 sections
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19
Nootropic Peptides: Semax Variants, Selank, Dihexa, and Cerebrolysin Compared
Nootropic Peptide Landscape: Mostly Russian-Origin, Limited Western Trials · Semax Family: Parent Molecule, Semax 4-7, and N-Acetyl Variants · Selank: Anxiolytic Heptapeptide and GABA Modulation
6 sections
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20
The Melanocortin System: α-MSH, NPY, Galanin, and Melanocortin-Receptor Pharmacology
Melanocortin System Primer: MC1R-MC5R, POMC, α/β/γ-MSH · α-MSH Biology: Pigmentation, Appetite, Inflammation · POMC and the Melanocortin Precursor Protein
6 sections
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21
Reading a Peptide COA & Evaluating Supplier Quality
What a COA is — and what it isn't · HPLC purity — what the percentage actually means · Mass spectrometry — confirming molecular identity
9 sections
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22
GHK-Cu (Copper Peptide): Evidence, Mechanisms & Regulatory Status
What GHK-Cu is — structure and natural occurrence · Mechanisms of action — what the evidence supports · Topical and cosmetic evidence — the strongest evidence base
7 sections
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23
Retatrutide: Evidence, Mechanism & Trial Status
What retatrutide is and where it stands in 2026 · Mechanism of action: what each receptor does · Phase 2 evidence: weight loss and metabolic outcomes
7 sections
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24
Tirzepatide: Evidence, Mechanism & Approved Uses
Regulatory Status: What Tirzepatide Is Actually Approved For · Mechanism of Action: The Dual GIP/GLP-1 Design · Approved Indication 1: Type 2 Diabetes — SURPASS Trial Evidence
7 sections
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25
Semaglutide: Evidence, Mechanism & Approved Uses
What Semaglutide Is and How It Is Structured · Mechanism of Action: From Receptor to Effect · Approved Indications and the Evidence Behind Each
7 sections
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26
FDA Peptide Tracker 2026
How to read this tracker · Tracker maintenance policy · Editorial caution
3 sections
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27
Semaglutide vs Tirzepatide vs Retatrutide: 3-Way GLP-1 Comparison
Bottom line: which one is strongest on evidence today? · Why mechanism matters: one receptor, two receptors, three receptors · Weight-loss numbers: useful signal, imperfect comparison
5 sections
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28
How PeptaHub Grades Peptide Evidence
The four evidence labels used on PeptaHub · Why study type matters · Endpoint quality: surrogate markers vs real outcomes
5 sections
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Explore more
COMPARE
Head-to-Head Comparisons
Side-by-side analysis of mechanism, reported study ranges, evidence level, and safety profile for peptide pairs.
RECOMMENDATIONS
Best Peptides by Goal
Curated, evidence-based peptide recommendations ranked by research quality and community evidence.
STACKING
Stacking Guides
Combination research context with mechanism synergy explanations, reported study ranges, and safety considerations.
DIRECTORY
Full Peptide Directory
Browse all peptide profiles with mechanisms, regulatory status, side effects, and regulatory status.
Education is the foundation of responsible peptide use — these guides exist to replace rumor with referenced, reviewable evidence.
— THE EDITORS