Types of Research Peptides You Need to Know

How this mechanism-class guide is organized

Laboratories do not buy “a peptide.” They buy a tool for a receptor, a pathway, or an analytical method. This page sorts the Nextday Peptides catalog the way PIs actually write protocols: by mechanism class, then by named SKU. Each named compound links to its product page so a purchase order can carry a stable URL next to the sequence. It is not a consumer “best of” list and it is not a ranking of personal outcomes.

If you still need the chemical definition of a research peptide (residue window, Fmoc SPPS, HPLC, RUO), read what are research peptides first. If you need the SKUs we actually see most often on incoming orders, use popular research peptides you need to know. This article is the map between those two: class, then compound, then documentation habits that stay the same across classes.

Classes below cover incretin and multi-agonist analogs; GHRH analogs and growth-hormone secretagogues; mitochondrial peptides; tissue-model fragments and their blends; the cathelicidin antimicrobial peptide; melanocortin ligands; neuroactive analogs; thymic and pineal bioregulators; and the small molecules that ride along on the same purchase orders. The last group is in the catalog because labs order it in the same cycle, not because a nucleoside analog is a peptide.

Language stays inside published-research framing. Compounds were studied in or investigated in preclinical models or in sponsor-run clinical programs. Those papers identify the molecule. They do not convert a research vial into a medicine, and they do not provide dosing, injection, cycles, or personal-use instructions. Nextday Peptides sells Research Use Only material not for human or veterinary use.

Incretin and multi-agonist research peptides

Retatrutide (GLP3-Reta) research peptide is the catalog name for LY3437943, a synthetic peptide engineered as a triple agonist at GLP-1, GIP, and glucagon receptors. Coskun and colleagues described that pharmacology; later sponsor-run trials investigated the molecule in people. On a research bench it is a long, acylated analog with the storage and HPLC habits of other incretin-class reagents. See also retatrutide versus tirzepatide versus semaglutide when a panel needs more than one incretin SKU.

Tirzepatide (GLP2-Tirz) is LY3298176, a dual agonist at GIP and GLP-1 receptors. Semaglutide (GLP1-Sema) is NN9535, a GLP-1 receptor agonist with a C-18 fatty-diacid side chain. Labs request these three when they are building comparative binding, signaling, or analytical methods. They are not interchangeable stocks. Store them as separate lot-coded boxes even when they arrive in one carton. Catalog nicknames are not unique keys.

Mazdutide (IBI362, LY3305677, OXM-3) is an oxyntomodulin analog investigated as a dual GLP-1 receptor / glucagon receptor agonist. Survodutide (BI 456906) is another dual GLP-1R/GCGR analog from a different sponsor lineage. Dual glucagon-family agonists are not the same molecule as a GIP/GLP-1 dual agonist and not the same as a triple agonist. If a protocol says “the dual,” write the receptor pair into the purchase order.

Cagrilintide is a long-acting amylin-analog peptide investigated in metabolic research, including combinations with GLP-1 receptor agonists in sponsor programs. It is an amylin-pathway ligand, not an incretin receptor agonist, but procurement groups file it next to the incretin drawer because the same discovery teams order both. Keep the mechanism label honest on the freezer box.

What this class shares operationally: long sequences, frequent acylation, TFA or acetate salts, and COAs that should include HPLC plus a mass. What it does not share: one storage meme, one reconstitution habit copied from a forum, or one “incretin” inventory code. Receiving should match each vial to its own lot PDF in the COA Library.

• Write the developmental code (LY3437943, LY3298176, NN9535, IBI362) on the PO when the protocol uses it
• Do not substitute mazdutide or survodutide for tirzepatide because both are “duals”
• File cagrilintide as an amylin analog, not as a GLP-1 agonist
• Keep dry incretin stock physically separate from any working solutions prepared under the lab SOP

GHRH analogs and growth-hormone secretagogues

This drawer holds two mechanism families that labs often order together and then mix up in the freezer. Growth hormone-releasing hormone (GHRH) analogs act at the GHRH receptor. Growth-hormone secretagogues (GHS) act at the ghrelin receptor (GHS-R). They are not the same ligand class. A blend SKU that combines them is a third purchasing object, not proof they are interchangeable singles.

CJC-1295 with DAC is DAC:GRF, a 30-amino-acid GHRH analog (CAS 446262-90-4 when that record applies) carrying a drug-affinity-complex modification investigated for prolonged GH-axis signaling in published human pharmacology work. CJC-1295 without DAC is Mod GRF 1-29, a 29-residue analog without that extension. Residue count is the identity check. Our CJC-1295 research guide exists because “CJC” on a packing list is not specific enough.

Sermorelin is GHRH (1-29), the classic truncated GHRH fragment used for decades in endocrine research. Tesamorelin is a stabilized GHRH analog investigated in sponsor programs, including published work in HIV-associated lipodystrophy models; the research vial remains RUO material. Do not treat sermorelin, tesamorelin, and either CJC variant as drop-in replacements without reading the sequence line.

Ipamorelin is a selective ghrelin-receptor pentapeptide secretagogue. GHRP-6 acetate and hexarelin acetate are earlier GHRP-family hexapeptides at the same receptor family with different selectivity and desensitization literature. Acetate in the SKU name is a salt note. Confirm it if your method is salt-sensitive. GHRP-6 is not hexarelin; hexarelin is not ipamorelin.

When a protocol calls for a GHRH analog plus a GHS, buy the singles your method can titrate, or buy a labeled blend only if the labeled composition is exactly what the method requires. Convenience purchasing is not method equivalence. File each lot. If the packing list abbreviation confuses receiving, photograph the vial and compare it to the live product page before shelving.

Mitochondrial research peptides

MOTS-c (mitochondrial open reading frame of the 12S rRNA-c) is a 16-amino-acid mitochondrial-derived peptide. Lee and colleagues described MOTS-c as a mitochondrially encoded peptide investigated in metabolic-homeostasis models. On this catalog it is a short, polar lyophilized peptide with ordinary dry-cake storage habits and a lot COA. It is not a small-molecule AMPK activator, even though some papers discuss overlapping pathway language.

SS-31 (elamipretide) is a mitochondria-targeting tetrapeptide (often written D-Arg-Dmt-Lys-Phe-NH2) investigated as a cardiolipin-interacting compound in published mitochondrial-medicine research. It is a different design idea from MOTS-c: one is a mitochondrial ORF peptide, the other is a synthetic targeting sequence. Do not inventory them under a single “mito peptide” item code.

Labs that run mitochondrial panels often add non-peptide tools in the same order: NAD+, AICAR, 5-Amino-1MQ. Those belong in the small-molecule section below. The only reason they appear in this paragraph is to stop receiving from dropping NAD+ into the MOTS-c box because both were on one packing list.

Identity work on short mitochondrial peptides is usually straightforward by mass. Still file the HPLC method. Short peptides can hide salt and scavenger peaks if the gradient is too steep. Treat the COA as you would for a longer analog: identity plus purity plus storage line.

Tissue-model and repair-pathway research peptides

BPC-157 is a 15-residue gastric pentadecapeptide investigated in a large preclinical literature on gastrointestinal and soft-tissue models. TB-500 in research catalogs is the thymosin β4 fragment used as a laboratory reagent (commonly the central actin-binding motif), not a license to treat thymosin biology as a consumer outcome. They are different sequences. A failed control on one does not diagnose the other.

KPV is the C-terminal Lys-Pro-Val tripeptide of α-MSH, studied in inflammation and epithelial models as a short melanocortin-related fragment. GHK-Cu is the copper(II) complex of the glycyl-L-histidyl-L-lysine tripeptide, investigated in extracellular-matrix and copper-peptide chemistry work. Light and metal-handling notes belong in the lab SOP for GHK-Cu; do not store the copper peptide loose under bench lighting for days.

GLOW is this catalog’s three-component research blend of TB-500, BPC-157, and GHK-Cu in a single lyophilized vial. KLOW adds KPV to those three. Blend SKUs exist for labs that intentionally want a labeled combination. They are a different purchasing object from the related singles. Do not assume stoichiometry, ratio, or separate COA coverage without reading the product page and the lot file. If your method needs independent titration of each component, buy singles.

Inventory systems should give blends their own item codes. Reusing the item code of a major component “because it is mostly BPC-157” destroys traceability. When an assay misbehaves, you need to know whether the freezer held a blend or a single lot. That sentence is the entire quality argument for this class.

• Match BPC-157 and TB-500 by sequence, not by “repair peptide” folklore names
• Treat GHK-Cu as a metal-peptide complex in the chemical-hygiene plan
• Order GLOW or KLOW only when the labeled combination is the method
• File blend COAs under the blend SKU, not under a single component

Antimicrobial peptides: LL-37 in research catalogs

LL-37 (CAP-18, hCAP18, CAS 154947-66-7) is the 37-amino-acid C-terminal fragment of human cathelicidin. Published work investigated LL-37 in innate-immunity, membrane-disruption, and host-defense peptide models. CAP-18 / hCAP18 names the parent protein; LL-37 is the fragment most research catalogs actually sell. Write the fragment name on the freezer box so nobody later assumes they have the full cathelin precursor.

Cationic antimicrobial peptides adsorb to glass and plastic more aggressively than a typical incretin analog. Your SOP should address container binding when you prepare assay standards. That is laboratory adsorption chemistry, not a dosing note. We do not publish working concentrations for any organism.

LL-37 lots should still carry HPLC plus mass. Truncation and oxidation are the impurity stories we see discussed on tickets. If a chromatogram looks unusually broad, ask whether the method ion-pairing matches a highly cationic 37-mer. Method mismatch is not automatically a bad lot.

Do not file LL-37 in the melanocortin drawer because both get discussed in “peptide immunology” seminars. Mechanism class is receptor or pathway, not seminar theme. The antimicrobial class on this catalog is currently this SKU; if your protocol needs a different host-defense peptide, it is a different order.

Melanocortin receptor ligands

Melanotan I (MT-1) is the linear analog often identified with afamelanotide-class [Nle4, D-Phe7]-α-MSH chemistry, investigated as a melanocortin-1 receptor ligand in pigmentation and photobiology research. Melanotan II (MT-2) is a cyclic heptapeptide melanocortin agonist with a different selectivity profile and a different impurity and handling story. Roman numerals matter. Autocomplete that drops the numeral is how labs receive the wrong analog.

PT-141 (bremelanotide) is a melanocortin receptor agonist derived from the Melanotan II series and investigated in sponsor-run sexual-function trials. The research-catalog vial is still RUO material. It is not a consumer product because a drug substance with the same stem was studied in people. Keep requisition language technical: sequence class, catalog slug, lot.

KPV, already listed under tissue-model fragments, is also a melanocortin-related tripeptide. If your lab files by receptor, put KPV with melanocortin; if you file by length and blend membership, put it with GLOW/KLOW. Pick one convention and write it down. Dual filing without a cross-reference is how a vial disappears.

Light and oxidation habits for melanocortin analogs belong in the SOP. Cyclic peptides and linear analogs do not share one chromatogram. Request the lot method if you will confirm identity in-house. Naming hygiene for this family is covered in more depth in catalog names, CAS, and peptide identifiers.

Neuroactive peptide analogs used in laboratory models

Semax is a Met-Glu-His-Phe-Pro-Gly-Pro analog of ACTH(4-10) investigated in Russian and later international literature on CNS and nootropic research models. Selank is a tuftsin analog investigated in anxiolytic and immune-modulation models. They are different sequences. A Semax/Selank blend, when offered, is a third SKU. Do not dissolve one label into the other because both are “Russian peptides” in informal speech.

DSIP (delta sleep-inducing peptide) is the nonapeptide Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu investigated historically in sleep-regulation research. The catalog name includes the historical phrase because that is how literature indexes it. It is not an instruction to use the vial for sleep, and it is not a consumer sleep product. File it as a nine-residue research peptide with a lot COA.

Pinealon is the tripeptide Glu-Asp-Arg, grouped in bioregulator literature with short CNS-facing peptides. Some labs file pinealon with Epitalon because both appear in Khavinson-school papers; others file it with Semax/Selank because the assays are neuro. Again, pick a convention. The product URL is the stable key.

Short neuroactive peptides are easy to weigh wrong because the fill is small and the powder is hygroscopic. Weighing discipline and NPC notes matter more here than on a 10 mg incretin cake. That is an analytical-prep issue under your SOP, not a dose calculation.

Peptide bioregulators and thymic peptides

Epitalon (Epithalon) is the tetrapeptide Ala-Glu-Asp-Gly associated with pineal-peptide research literature. Spelling variants are the same intended sequence when the spec table agrees. Thymalin (thymulin) listings on research catalogs refer to thymic peptide preparations; thymulin in the strict sense is a zinc-binding nonapeptide, and complex thymic extracts are not the same purchasing object as a single synthetic sequence. Read the spec table before you treat two “thymic” hits as equivalent.

Thymosin alpha-1 is a 28-residue thymic peptide investigated in immune-model and published clinical-research settings as a defined sequence (often N-acetylated Ser-Asp-Ala-Val…). It is not thymosin β4, not TB-500, and not thymalin. Residue count plus the alpha-1 name should appear on the box. We still see receiving tickets that shelved thymosin alpha-1 next to TB-500 because both said “thymosin.”

Bioregulator catalogs grew up with a folklore naming culture. Your LIMS does not have to inherit that culture. Use sequence, residue count, and slug. If a paper uses a Cyrillic trade name, paste the residues into the PO. Five minutes of identifier work is cheaper than a wrong tetrapeptide in a six-week assay.

Purity expectations are the same as the rest of the catalog: HPLC plus identity, lot-linked. Short acidic peptides can give odd HPLC traces if the ion-pairing is weak. Ask for the method if the area percent is the number your QA group will quote.

Small molecules sold alongside research peptides

Not everything in a peptide cart is a peptide. AICAR (acadesine, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, CAS 2627-69-2) is a cell-permeable nucleoside analog used as an AMPK-pathway tool compound. Narkar and colleagues investigated AMPK-pathway ligands in metabolic and exercise-mimetic models. Handle AICAR under a small-molecule chemical-hygiene SOP, not a peptide reconstitution SOP copied from an incretin page.

5-Amino-1MQ is 5-amino-1-methylquinolinium (CAS 42464-96-0), a quaternary quinolinium used as a nicotinamide N-methyltransferase (NNMT) tool compound. It is not a peptide. See what is 5-Amino-1MQ for structure and laboratory framing. NAD+ is β-nicotinamide adenine dinucleotide, an endogenous dinucleotide coenzyme, also not a peptide. Labs order it because mitochondrial and metabolic panels want a cofactor standard in the same shipment.

SLU-PP-332 is an estrogen-related receptor (ERR) agonist small molecule investigated as an exercise-mimetic tool in published metabolic research. It is filed on this catalog because the same discovery groups that buy MOTS-c and AICAR ask for it. Put it in the small-molecule inventory, with its own SDS, not in the lyophilized-peptide box.

Blends that mix a peptide with small molecules are still blends. Read the lot file for which components were tested how. A single HPLC percentage cannot describe three chemical classes unless the PDF says it does. When in doubt, buy singles for the components your method must titrate.

Research peptide classes at a glance

Use this table when a purchasing agent needs a one-page map. Links on product pages carry the full spec tables. Mechanism labels are for laboratory filing, not outcome claims.

If a new SKU lands on an order and does not fit a row, do not force it. Add a class in the lab wiki. Wrong classification is how SS-31 ends up next to TB-500 because both are “four-ish residues and popular.”

How labs choose a class without shopping for outcomes

Choose the class from the assay, not from a search trend. A GLP-1/GIP/glucagon signaling panel wants the incretin drawer. A GHRH-receptor internalization assay wants a GHRH analog with the correct residue count. A cardiolipin-binding study wants SS-31, not MOTS-c. Write the receptor or pathway on the requisition before anyone opens the catalog.

When two SKUs share a class, differentiate by sequence, modification, and literature code. Retatrutide is not tirzepatide. CJC with DAC is not Mod GRF 1-29. MT-1 is not MT-2. The class table gets you to the drawer; the product page and the lot file get you to the molecule.

When a PI asks for a blend “to simplify,” ask whether the method can tolerate a fixed ratio. If the answer is no, buy singles. If the answer is yes, buy the blend and file it as a blend. We see more documentation failures on blends than on singles because people file them under the first peptide in the name.

Price and fill size come after identity. A cheaper fragment in the wrong class is not a saving. For how laboratories talk about purity once the class and sequence are correct, use how laboratories evaluate peptide purity and the HPLC purity article.

Documentation and RUO habits that apply across classes

Every class still needs the same intake loop. Match PO, packing list, and vial lot. Download the PDF from the COA Library. Log freezer ID and rack. Keep RUO labeling intact. Prompt receiving after delivery from Florida, North Carolina, or California warehouses matters more than the carrier’s packaging language. Same-day processing targets orders before 3:30 PM Eastern, Monday–Saturday, after payment clears; see the shipping and delivery policy.

Shared freezers are where classes collide. Use project-coded boxes and written checkout rules. Do not store dry incretin analogs in the same unlabeled bag as reconstituted leftovers from a tissue-model fragment. Dry stock and solutions have different risk profiles. Color, haze, or unexpected particulates after laboratory reconstitution are stop-and-document events under most SOPs.

If a later experiment fails a control, the trail (class, sequence, lot, storage location, arrival condition) matters more than a generic blog tip. Storage notes and purity notes belong together. A vial that spent a week in a warm mailroom is a different story than a vial with an unexpected HPLC result on a correctly handled lot.

Nextday Peptides supplies RUO materials for laboratory work only. This class guide is a filing aid. It is not medical advice, a personal-use catalog, or a substitution chart for clinical products. If your work is not laboratory research, do not order from this list.

Bottom line for buyers mapping peptide types

Map the assay to a mechanism class, then to a named SKU with a product URL, then to a lot file. That three-step path is how research-peptide types stay usable in a notebook. Skipping the class step produces nickname orders. Skipping the lot step produces un-investigable failures.

The compounds named above cover the drawers U.S. research buyers ask us to stock: incretin multi-agonists, GHRH and GHS ligands, mitochondrial peptides, tissue-model fragments and blends, LL-37, melanocortin ligands, neuroactive analogs, bioregulators, and the small molecules that travel with them.

If you take only one habit from this page, write the receptor or pathway on the purchase order next to the catalog name. Everything else in class discipline tends to follow once that line exists. Nextday Peptides sells Research Use Only material not for human or veterinary use.