Weight & Metabolism
ApprovedApproved Pharmaceutical
Semaglutide
The benchmark GLP-1 peptide that reshaped diabetes and obesity medicine by slowing digestion and turning down hunger signals in the brain.
Evidence Tier✓ FDA-Approved (Level 1)
Therapept Reference Platform
Understand peptides without the hype.
Learn what different peptides are, why people are interested in them, how they work, and what the research actually says — explained in plain English, grounded in primary literature, with zero marketing spin.
Search 32 compounds, clinical trials, dosing files, and guides
The Three Peptide Worlds
Scientific RealitiesKnow what kind of compound you are researching
1. FDA-Approved TherapeuticsApproved
Prescription medicines validated in multi-year human trials (e.g. Wegovy, Zepbound, Egrifta). Documented safety and proven human efficacy.
2. Investigational Drug CandidatesClinical Trials
Molecules in registered, ongoing clinical trials undergoing evaluation (e.g. Retatrutide in Phase 3). Promising data, not yet approved.
3. Preclinical Research ChemicalsPreclinical
Substances studied in cell cultures or animal models with zero completed human Phase 3 trials (e.g. BPC-157, TB-500). Unproven human safety.
Peptide Foundations
What exactly is a peptide?
Your body already runs on peptides. A peptide is simply a short chain of amino acids — the same chemical building blocks that make up proteins. While a full protein consists of hundreds or thousands of amino acids folded into complex three-dimensional structures, a peptide is a shorter sequence (typically under 50 amino acids) that acts like a precision biological messenger.
Amino Acids: Individual building blocksPeptides: 2 to 50 amino acids (messengers)Proteins: 50+ amino acids (structural/enzymes)
Why Are Peptides Researched?
- 1.Receptor Specificity: They target specific cell receptors with minimal off-target interference.
- 2.Natural Degradation: Cleared into harmless natural amino acids by ordinary metabolic enzymes.
- 3.The Delivery Problem: Stomach acid degrades most peptides, which is why most require subcutaneous injection.
Class Architecture Comparison
The three peptide classes ordinary adults encounter
From landmark prescription metabolic drugs to experimental repair chemicals — understand the vast differences in target receptors, clinical proof, and regulatory reality.
Class 1 · Incretin MimeticsMetabolic
Gut & Pancreatic Mimetics
Examples: Semaglutide · Tirzepatide · Retatrutide
Receptor Targets:GLP-1, GIP, and Glucagon receptors in the brain, pancreas, and liver.
Human Evidence Level:Thousands of patients in multi-year Phase 3 randomized controlled trials (NEJM, Lancet) proving 15% to 24%+ average weight loss.
Regulatory Status:FDA-approved prescriptions (Wegovy, Zepbound) or late Phase 3 investigational candidates (Retatrutide).
Class 2 · Endocrine SecretagoguesPituitary Axis
Growth Hormone-Releasing Factors
Examples: Tesamorelin · Sermorelin · Ipamorelin
Receptor Targets:Pituitary somatotroph GHRH receptors, encouraging natural pulsatile GH release and liver IGF-1 synthesis.
Human Evidence Level:Tesamorelin is validated in NEJM Phase 3 trials specifically for visceral fat in HIV lipodystrophy. No large-scale evidence for cosmetic anti-aging.
Regulatory Status:FDA-approved for targeted medical indication (EGRIFTA) or compounding restricted.
Class 3 · Preclinical Repair PeptidesPreclinical
Tissue-Protective Fragments
Examples: BPC-157 · TB-500 · KPV
Pathways Investigated:Angiogenesis (VEGF capillary sprouting), cell migration (FAK-paxillin), and mucosal barrier defense.
Human Evidence Level:Preclinical rodent models only. Zero completed Phase 3 human clinical trials proving safety or clinical efficacy in humans.
Regulatory Status:Unapproved research chemicals; FDA Category 2 bulk compounding safety alerts; prohibited in competitive sports by WADA.
Interactive Visual Discovery
What are you curious about?
Explore peptide science organized by physiological research domain. Select a topic below to discover how each compound works, what has actually been tested in humans, and which remain unapproved laboratory chemicals.
Weight & MetabolismIncretin hormones, gastric motility, and metabolic expenditure
Peptides that simulate natural gut and pancreatic hormones to delay digestion, dampen appetite in the brain, and stimulate metabolic rate.
Weight & Metabolism
ApprovedApproved Pharmaceutical
Tirzepatide
A dual-hormone incretin that activates both GIP and GLP-1 receptors, producing greater average weight reduction and metabolic control than single-target therapies.
Evidence Tier✓ FDA-Approved (Level 1)
Weight & Metabolism
InvestigationalLate-Stage Clinical Trials
Retatrutide
An experimental triple-hormone peptide that set clinical trial records by reducing average body weight by up to 24.2% in Phase 2.
Evidence Tier🔬 Human Trials (Level 2)
Research Context: Inclusion under a research topic indicates scientific investigation or active clinical trials in that physiological area. It does NOT constitute medical endorsement, therapeutic indication, or safety verification.
Anatomical Research Mapping
Where peptide science intersects with the human body
Peptides do not act in a vacuum. Each compound is engineered or discovered to interact with specific receptors located in distinct tissues and organ systems. Select an anatomical area to see how the underlying biology is being researched.
Tap any hotspot to inspect body system
Target Region
Metabolic: Liver, Pancreas & Adipose
Incretin signaling, glucose clearance, and caloric expenditure
System Function
Coordinates energy storage, blood sugar homeostasis, and basal metabolic burn across liver, pancreas, and fat tissue.
Peptide Signaling Mechanisms
Multi-receptor incretin peptides activate GLP-1 (satiety), GIP (fat cell sensitivity & nausea buffering), and Glucagon (liver thermogenesis) to dramatically shift caloric balance.
Current Evidentiary Status: Highest human evidence tier in peptide science. Multiple FDA-approved medications (Wegovy, Zepbound) with Phase 3 trials involving tens of thousands of patients.
Associated Compounds Investigated in this System
RetatrutideLate-Stage Clinical
Triple GLP-1/GIP/Glucagon agonist in Phase 3 trials
TirzepatideApproved
Dual GIP/GLP-1 receptor agonist
SemaglutideApproved
Selective GLP-1 receptor mono-agonist
MOTS-cPreclinical / Investigational
Mitochondrial AMPK metabolic activator
Scientific Transparency: This visualization illustrates physiological tissue targets and receptor localization discussed in scientific literature. It does NOT imply that any unapproved compound safely or effectively treats conditions in that anatomical area.
Visual Stories
Featured compound deep-dives
Detailed visual explorations of the most discussed molecules in current metabolic and physiological research.
Flagship Tri-AgonistPhase 3
Retatrutide
Experimental triple hormone receptor agonist (GLP-1, GIP, Glucagon) that demonstrated up to 24.2% mean weight reduction in Phase 2 trials.
FDA-ApprovedDual Agonist
Tirzepatide
Dual GIP/GLP-1 receptor agonist commercialized as Mounjaro and Zepbound, demonstrating over 20% average clinical weight loss.
FDA-ApprovedGHRH Analogue
Tesamorelin
Stabilized GHRH peptide approved specifically for visceral organ fat reduction in HIV lipodystrophy, preserving pituitary somatostatin feedback.
Preclinical OnlyWADA Banned
BPC-157
Synthesized stomach protein fragment researched in rodents for angiogenesis and tendon repair, with zero completed human trials.
Landmark Human Clinical Trials
What has actually been demonstrated in human medicine?
We separate peer-reviewed human trials from animal and laboratory assays. A hundred rodent studies do not equal a human trial. Here is the primary evidence published in the New England Journal of Medicine:
RetatrutideClinical trialNew England Journal of Medicine (2023)
NCT04881760 ↗Triple-hormone-receptor agonist retatrutide for obesity — a Phase 2 trial
Jastreboff AM, Kaplan LM, Frías JP, Wu Q, Du Y, Gurbuz S, Coskun T, Haupt A, Milicevic Z, Hartman ML; Retatrutide Phase 2 Obesity Trial Investigators
1Who was studied?
Population: Adults with obesity in a registered Phase 2 programmeSample Size: n = n = 338
2What was investigated?
Objective: To test once-weekly retatrutide versus placebo for body-weight change over 48 weeks.Endpoint: Body-weight change and related endpoints in Phase 2
3What did researchers do? (Protocol)
Design: Randomised, double-blind, placebo-controlled Phase 2 trial · Duration: 48 weeks, with the primary endpoint at week 24 · Comparator: Placebo
Intervention: Once-weekly subcutaneous retatrutide at several dose levels and starting-dose schedules
4Published Findings & Observations
Phase 2 randomised trial of investigational retatrutide, a GIP/GLP-1/glucagon receptor agonist, versus placebo in adults with obesity. Primary results were published in NEJM. This is investigational-drug evidence under medical supervision — not research-chemical catalogue evidence, and not an approved-product label.
5Evidence Gaps & Study Limitations
Phase 2. Product, dose and supervision are those of the sponsor programme. Findings do not transfer to unapproved look-alike products, and they do not make retatrutide interchangeable with semaglutide or tirzepatide.
Record ID: retatrutide-jastreboff-2023
TirzepatideClinical trialNew England Journal of Medicine (2022)
NCT04184622 ↗Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1)
Jastreboff AM, Aronne LJ, Ahmad NN, et al.
1Who was studied?
Population: Adults with obesity, or overweight plus a weight-related complication, without diabetesSample Size: n = n = 2,539
2What was investigated?
Objective: To test once-weekly tirzepatide versus placebo for body-weight change in SURMOUNT-1.Endpoint: Body-weight change in the SURMOUNT-1 trial
3What did researchers do? (Protocol)
Design: Randomised, double-blind, placebo-controlled trial · Duration: 72 weeks, including a 20-week dose-escalation period · Comparator: Placebo, randomised 1:1:1:1
Intervention: Once-weekly subcutaneous tirzepatide at one of three maintenance dose levels
4Published Findings & Observations
Phase 3 randomised trial of approved tirzepatide doses versus placebo, published in NEJM. Evidence for the approved products, not for unapproved look-alikes.
5Evidence Gaps & Study Limitations
Approved-product trial. Population, dose and manufacture are those of the labelled programme.
Record ID: tirzepatide-jastreboff-2022
Ask Therapept Intelligence Engine
Direct, plain-English answers to real peptide questions
Skip forum hearsay and sponsored influencer claims. Therapept translates peer-reviewed literature, receptor pharmacology, and regulatory registries into transparent, non-promotional answers.
Weight & Metabolism
What is retatrutide?
Experimental triple-agonist (GLP-1, GIP, Glucagon) that reduced average body weight up to 24.2% in Phase 2 trials.
Read Answer & Trial Evidence →
Incretin Mechanism
How does retatrutide differ from tirzepatide?
Dual agonist vs triple agonist: adding glucagon receptor activation to stimulate hepatic thermogenesis and energy burn.
Read Answer & Trial Evidence →
Endocrine Axis
What does tesamorelin do?
Stabilized GHRH analogue approved for visceral fat in HIV lipodystrophy without shutting down pituitary negative feedback.
Read Answer & Trial Evidence →
Preclinical Reality
What is BPC-157 being studied for?
Rodent tendon and gut models vs the clinical reality of zero completed human Phase 3 trials and FDA compounding alerts.
Read Answer & Trial Evidence →
Laboratory Testing
What is a Certificate of Analysis (COA)?
HPLC purity percentage vs LC-MS molecular weight identity, net peptide content, and spotting fabricated test reports.
Read Answer & Trial Evidence →
Clinical Evidence
Which compounds have human trials?
Explore approved drugs vs active investigational trials vs compounds with zero human evidence.
Read Answer & Trial Evidence →
Clinical Commentary
Real-world perspectives from clinicians and trialists
Curated insights, podcast discussions, and regulatory hearings from verified physicians, researchers, and scientific societies.
Associate Professor of Medicine and Pediatrics, Yale School of Medicine
Dr. Ania M. Jastreboff, M.D., Ph.D.
As lead investigator of the published Phase 2 retatrutide trial, Dr. Jastreboff explained that retatrutide's unprecedented 24.2% average weight reduction stems from activating three separate hormone systems simultaneously: GLP-1 and GIP for appetite suppression and insulin sensitivity, combined with glucagon receptor activation to stimulate energy expenditure and reduce liver fat.
M.D. (Stanford University School of Medicine)
Dr. Peter Attia, M.D.
Dr. Attia publicly analyzes the metabolic effects of GLP-1 and multi-agonist incretins, cautioning that rapid scale weight loss often includes 25% to 40% skeletal muscle and lean organ mass loss if progressive heavy resistance training and adequate dietary protein (roughly 1 gram per pound of target body weight) are not strictly prioritized.
Board-certified Orthopedic Surgeon
Dr. William A. Seeds, M.D.
Dr. Seeds details the clinical distinction between continuous GHRH exposure and physiological pulsatile secretagogues. He argues that short-acting GHRH analogues (like Mod GRF 1-29 or sermorelin, paired with ipamorelin) are preferable for cellular health because they stimulate natural pituitary pulses while preserving negative feedback loops, whereas long-acting continuous stimulation (such as CJC-1295 DAC) risks pituitary receptor desensitization.
Interactive Tools
Practical educational resources
Tools designed to eliminate mathematical errors and clarify laboratory testing terminology.
Guide
Preparation & Diluents
Bacteriostatic water vs sterile water, multi-dose vial safety, and proper reconstitution flow.
CalculatorReconstitution Math
Convert vial milligrams and diluent milliliters into precise syringe unit measurements.
Analysis ToolCOA Detective
Learn how to inspect laboratory Certificates of Analysis for net weight, purity, and fraudulent reports.
DirectoryTesting Laboratories
Directory of 12 independent analytical chemistry labs equipped with HPLC and LC-MS instruments.
The Peptide Universe
Every compound in the file, mapped by its regulatory family and evidence shape
Approved drugs on one side, unapproved research compounds on the other. Node size represents indexed evidence records; color indicates the dominant evidence class.
Horizontal bands are regulatory families. Node size is the number of indexed evidence records; color is the record’s dominant evidence class (blue human · violet animal · teal in-vitro · rust regulatory · gray review). Positions do not encode any ranking.
Research Transparency
Every metric is derived from published data
Therapept does not estimate, project, or fabricate numbers. Every count is computed directly from primary literature at build time.
32
Compound Records
74
Evidence Records
13
Human Trial Records
12
Dosing Files
12
Testing Laboratories
20
Compounding Alerts
Intelligence
Analysis, regulatory updates, and testing
Original editorial investigations into compounding regulations, analytical chemistry, and industry developments.
Regulation
What FDA’s July 2026 PCAC Meeting Actually Decided — and What It Did Not
On 23–24 July 2026 FDA’s Pharmacy Compounding Advisory Committee discussed fourteen salt and free-base forms of seven peptides. Staff proposed that none of them be added to the 503A Bulks List. That proposal is not a listing decision, and a committee recommendation is not one either.
12 Sept 2026 · 10 min
Regulatory
FDA Warning-Letter Patterns in Peptide Marketing
Published FDA warning letters and unapproved-drug communications in this sector cluster on intended-use claims and unapproved products — not on whether a COA percentage was high.
12 Sept 2026 · 8 min
Regulatory
A Peptide Regulatory Timeline — What Moved in 2026
FDA’s Pharmacy Compounding Advisory Committee met 23–24 July 2026 on several peptide bulk substances. Trade press reported recommendations. A recommendation is not a listing and not an approval. Identity records stay conservative until FDA publishes the primary instrument.
12 Sept 2026 · 8 min