#identity
15 pieces tagged identity.
- HandlingWhy some peptides dissolve badly: charge, hydrophobicity and gellingNet charge, isoelectric point, hydrophobic residue content and beta-sheet self-assembly decide whether a peptide dissolves clear, turns cloudy or gels. The chemistry, with worked examples from published sequences.
- The moleculesTB-500 and thymosin beta-4 are not the same moleculeThymosin beta-4 is a 43-residue protein. TB-500 is a seven-residue synthetic fragment of it. Here is the identity of each, the thymosin alpha-1 mix-up, and the status of all three as of September 2026.
- The moleculesSermorelin, tesamorelin, ipamorelin and CJC-1295 comparedThree of these are GHRH analogues; ipamorelin is a five-residue ghrelin-receptor ligand. One had an approved product that was discontinued, one has an approved product on the market, two have none. Identity and status side by side.
- The moleculesSemax and Selank: two heptapeptides and their US statusSemax (MEHFPGP) is four residues of ACTH plus a Pro-Gly-Pro tail; Selank (TKPRPGP) is the tetrapeptide tuftsin plus the same tail. Where each came from, what the spelling variants mean, and their status as of September 2026.
- Reading the paperworkA peptide paperwork glossaryThirty-six entries for the terms that appear on peptide certificates, labels and regulatory pages, each defined in one to three sentences from a primary source and linked to the piece that explains it.
- The moleculesNAD+, 5-amino-1MQ and glutathione: which are peptides?Three catalog staples that share a shelf with peptides. Only one is a peptide. What each molecule actually is, from PubChem, and why the distinction changes what a certificate should show.
- The moleculesMelanotan II, PT-141 and afamelanotide: one parent, three analoguesAfamelanotide, Melanotan II and bremelanotide all descend from the 13-residue hormone alpha-MSH. Two became approved drugs; Melanotan II never did. Structures, lineage, FDA's own words on MT-II, and status as of September 2026.
- Reading the paperworkMass spectrometry identity: what a one-dalton match provesESI and MALDI in plain terms, why a peptide shows up at several m/z values at once, monoisotopic against average mass, and a worked example on a stocked fifteen-residue peptide from its PubChem entry.
- The moleculesHow to read a peptide sequenceThe one- and three-letter codes, which end is which, what Ac- and -NH2 mean, how D-residues, rings and lipids are written, and four worked examples from the catalog.
- The moleculesGHK-Cu: why the powder is blue and what copper peptide meansGHK-Cu is the tripeptide glycyl-histidyl-lysine holding one copper(II) ion. The copper is what makes it blue, what makes it a different molecule from GHK, and what its two INCI names are about. Status as of September 2026.
- HandlingFreeze-thaw, aliquots and the residues that oxidizeWhich amino acids oxidize, deamidate or hydrolyse, what freezing and thawing do to a solution physically, what manufacturers' guides say about repeated freezing, and where those residues sit in the sequences we stock.
- The moleculesEpithalon, epitalon and the word bioregulatorOne tetrapeptide, four spellings, and a term that is not a pharmacological class. What AEDG is, where it came from, what the Khavinson school means by bioregulator, and its US status as of September 21, 2026.
- The moleculesCJC-1295 with DAC and without: what the drug affinity complex changesCJC-1295 is a 30-residue GHRH analogue carrying a maleimide group that bonds to serum albumin. The version sold without DAC is a different, 29-residue molecule. Identity, lineage and 2026 status.
- The moleculesCagrilintide is an amylin analogue, not a GLP-1Cagrilintide descends from the pancreatic hormone amylin, not from GLP-1. What the molecule is, how it was engineered, why it is paired with semaglutide in trials, and its status as of September 21, 2026.
- Where the line isAre peptides steroids? The chemistry and the law behind the questionNo. A peptide is a chain of amino acids joined by amide bonds; a steroid is a lipid built on a four-ring carbon skeleton. Why the two are made, regulated and listed differently, with a comparison table.
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