The Retatrutide Hub
The complete, vendor-neutral guide to the most talked-about peptide in the world — FDA status, the record-setting TRIUMPH trial data, mechanism, dosing, side effects, and how access really works. Continuously updated.
Interactive Tools
12 tools no other peptide site has
Calculators, builders, and visualizers designed to replace guesswork with precision.
Reconstitution Calculator
25 peptide presets, visual syringe rendering, precise dosage math. The tool every peptide user needs first.
Protocol Builder
27 protocols across 9 goals with Gantt-style timeline visualization. Build complete dosing schedules in minutes.
Interaction Checker
35+ interaction pairs with conflict alerts and auto-generated daily schedules.
Comparison Tool
Radar chart comparison of up to 3 peptides across twelve metrics.
Half-Life Visualizer
Pharmacokinetic modeling with multi-compound overlay plotting.
Vendor Evaluator
Score any vendor against 20 criteria — COA, HPLC, sterility, and more.
Cost Calculator
Cost-per-protocol breakdown with shopping list generation.
Mixing Guide
5 sub-guides with interactive body map for injection sites.
Reference · 296 Peptides
Every peptide,
one reference.
Mechanism, dosing, evidence level, and sourced references for every peptide with published research — from FDA-approved compounds to clinical-trial candidates.
Latest Research
Articles & guides
How GLP-1 Drugs Interact With Common Prescriptions: A Clinical Guide (2026)
Semaglutide, tirzepatide, and other GLP-1 agonists interact with over 30 common prescription medications. A detailed reference covering mechanism, severity, and clinical management.
Read the full guideIndustry news
FDA action, trial readouts, and peptide pipeline developments — by the Grey Peptides News Desk.
REDEFINE-1 Body Composition Data: How CagriSema Affects Muscle Mass
New post-hoc DXA findings from Novo Nordisk's pivotal CagriSema trial, presented at the European Congress on Obesity 2026, examine the muscle-mass picture behind 20%+ weight loss.
The FDA Just Proposed Ending Mass GLP-1 Compounding — Here's What It Actually Means
On April 30, the FDA published a proposed rule that would permanently exclude semaglutide, tirzepatide, and liraglutide from the 503B bulks list. The compounding workaround is closing.
PIONEER TEENS: Oral Semaglutide Posts Positive Phase 3 Results in Pediatric T2D
Novo Nordisk reported topline results from a phase 3a trial of oral semaglutide in patients aged 10 to 17 with type 2 diabetes — the first oral GLP-1 RA to clear a pivotal study in this group.
FDA Pulls 12 Peptides Off Its "Do Not Compound" List — What Changes, and What Doesn't
On April 15, the FDA quietly removed twelve peptide bulk substances from Category 2 of the 503A interim policy. A July advisory-committee vote will decide what happens next.
Wegovy HD Cleared in 54 Days: What the FDA's New Voucher Pathway Means for Peptide Drugs
The FDA approved semaglutide 7.2 mg on March 19 — fifty-four days after filing — using the Commissioner's National Priority Voucher pathway. The precedent is more complicated than the speed.
Foundayo (Orforglipron) Approved: The First Oral Small-Molecule GLP-1 for Weight Loss
On April 1, the FDA approved Eli Lilly's orforglipron under the brand Foundayo. Unlike oral Wegovy, it's a small-molecule pill that doesn't require an empty stomach.