Compound Notes · Jul 28, 2026
Peptide Comparisons: The Full Index
Comparisons are usually written as though any two compounds can be lined up against each other. Most cannot. These are grouped by what the pair genuinely shares, because that is what determines whether a comparison says anything.
Incretin analogues
All three act at overlapping incretin receptors and differ in how many they target. Genuinely comparable.
- Retatrutide vs Tirzepatide — triple agonist against dual
- Retatrutide vs Semaglutide — triple against single
- Tirzepatide vs Semaglutide — dual against single
These are the largest molecules in the catalogue: semaglutide 4,113.58 g/mol, tirzepatide 4,813.45, retatrutide 4,731.32. All three sit in the range where synthesis is hard and purity between suppliers varies most.
Growth hormone axis
Two receptor families that get treated as one category.
- Ipamorelin vs CJC-1295 — GHRP against GHRH analogue
- Ipamorelin vs Tesamorelin — the widest size gap here, 7x
- Tesamorelin vs CJC-1295 — two GHRH analogues, genuinely alike
Melanocortin
- PT-141 vs Melanotan II — 1 g/mol apart, which makes identity confirmation the check that matters
Repair and recovery
Frequently grouped, chemically unrelated.
- BPC-157 vs TB-500
- BPC-157 vs GHK-Cu — peptide against copper complex
- TB-500 vs GHK-Cu — 12x size gap
Nootropic
Reading any of these
Two things determine whether a comparison is useful.
Molecular weight predicts purity variance. Short peptides are made well by almost anyone. Long chains separate good suppliers from bad, because deletion sequences accumulate with every coupling step and are hard to remove.
Class determines handling. A copper complex, a sulfur-containing chain and a plain short peptide fail in different ways and need different storage.
Neither of those is visible from a price or a purity percentage alone.
Related
- Peptide glossary
- Why purity figures differ between suppliers
- How to read a certificate of analysis
- Published lab results, by lot
All compounds referenced are supplied as laboratory reagents for research use only. Not for human or veterinary use.
Related reading
- Ipamorelin vs Tesamorelin: Different Receptors, Seven Times the Size
A 712 g/mol pentapeptide acting at one receptor family against a 5,136 g/mol GHRH analogue acting at another. Almost nothing about these two is comparable except that people compare them.
- TB-500 vs GHK-Cu: The Largest and Smallest in the Catalogue
A 4,963 g/mol peptide against a 402 g/mol copper complex. A twelvefold size difference changes everything about how the two are made, priced and handled.
- Tesamorelin vs CJC-1295: Two GHRH Analogues, Very Different Sizes
Same receptor family, same design idea, and a 1,700 g/mol gap between them. What that gap means for synthesis, purity and price.
- Ipamorelin vs CJC-1295: Two Different Molecule Classes
One is a small pentapeptide, the other is nearly five times its size and works on a different receptor family entirely. The comparison people make most often is between two things that are not the same kind of thing.