Reading a Peptide Name: Sequence Notation, Salt Forms and Modifications
A decoder for peptide vial labels: how sequences are written, what the number in a name actually means, and what DAC, LR3, Mod GRF 1-29, fragment, acetate and arginate tell you about the molecule.
TL;DR: The name and label carry real information
Sequences read N-terminus to C-terminus. A trailing "NH2" means a C-terminal amide; an "Ac-" prefix means an N-terminal acetyl cap. The number means different things. In "Mod GRF 1-29" and "HGH frag 176-191" the digits are residue positions on the parent protein; in BPC-157, CJC-1295 and TB-500 they are lab or company compound designations, not sequence coordinates. DAC (drug-affinity-complex) is an albumin-binding modification that extends half-life from minutes to days (PMID 15817669, 16352683). Critically, the stocked CJC-1295 is the no-DAC form, so that multi-day profile does not describe it. LR3 (Long-R3) is an IGF-1 modification with much reduced IGF-binding-protein affinity (PMID 7561636). Salt form matters for handling. Synthesis leaves peptides as the trifluoroacetate (TFA) salt, and acetate is the preferred counterion, with arginate an alternative that shifts solubility (PMID 10567002).
A peptide vial label looks like alphabet soup, but almost every part of it is meaningful. Learning to parse it tells you what the molecule actually is, and, just as importantly, what it is not. This is a definitional nomenclature-and-chemistry reference for laboratory research handling only. It gives no dosing and no reconstitution-for-use guidance; salt-form and solubility content is handling chemistry, not usage. Preclinical findings are labelled as such, and compounds named only to explain a convention are comparison-only.
Bacteriostatic water and research supplies
How a Sequence Is Written
Peptides are written from the N-terminus to the C-terminus using either three-letter codes (Gly-Glu-Pro-Pro-Pro and so on) or one-letter codes, naming each residue in order (standard convention). Two common decorations tell you about the ends of the chain: a trailing NH2 means the C-terminus is amidated (a C-terminal amide, which resists carboxypeptidases), and an Ac- prefix means the N-terminus carries an acetyl cap. These end modifications are among the simplest ways a synthetic peptide is stabilized against the exopeptidases that chew inward from the ends.
What the Number Actually Means
This is the most common source of confusion, because the digits in a peptide name are not one kind of thing.
- Residue positions on a parent protein. In "Mod GRF 1-29", the 1-29 means residues 1 through 29 of the parent growth-hormone-releasing hormone. In "HGH frag 176-191", the 176-191 means residues 176 through 191 of growth hormone. The number is a coordinate.
- A lab or company compound designation. In BPC-157, CJC-1295 and TB-500, the number is just an identifier (CJC comes from the company ConjuChem), not a sequence coordinate. BPC-157 is a 15-amino-acid pentadecapeptide isolated from gastric juice (PMID 40005999); the "157" is not its length or position.
So "1-29" tells you something structural, while "157" tells you nothing structural at all. Reading the number correctly is the first decoding skill.
DAC: The Albumin Anchor (and Why It Matters for CJC-1295)
DAC stands for drug-affinity-complex, and it is a specific chemical modification. A maleimidopropionyl group is added to hGRF(1-29); in the body it reacts with the free thiol on Cys34 of circulating serum albumin, forming a stable covalent albumin complex, and CJC-1295 was detectable in plasma beyond 72 hours (PMID 15817669). The result is dramatic: CJC-1295 with DAC had an estimated plasma half-life of 5.8 to 8.1 days and elevated IGF-1 for 9 to 11 days in a healthy-adult study (PMID 16352683).
The stocked CJC-1295 is the no-DAC form
That multi-day half-life and the human GH/IGF-1 data belong to CJC-1295 with DAC specifically. The stocked CJC-1295 is the no-DAC "Mod GRF 1-29" form, which is short-acting (minutes-scale) and does not share the DAC pharmacokinetic profile. This is the single most important nomenclature distinction on the label: "with DAC" and "no-DAC / Mod GRF 1-29" are pharmacokinetically different molecules that share a base sequence.
CJC-1295 without DAC (Mod GRF 1-29) is a short-acting GHRH(1-29) analog for GH/IGF-1 research. Research-grade lyophilized powder, specified purity >=99% (HPLC). Laboratory use only.
LR3, Fragment and the Other Modification Suffixes
LR3 (Long-R3). This suffix, as in IGF-1 LR3, denotes an IGF-1 analogue carrying an Arg3 substitution plus a 13-residue N-terminal extension, giving it much reduced affinity for the IGF-binding proteins, which, as a biochemical and preclinical research finding with no demonstrated human efficacy or safety implication, changes its distribution and circulating behaviour relative to native IGF-1 (PMID 7561636). (The exact reduction in binding is often quoted as a precise fold-number from secondary sources; the primary literature states "much reduced affinity", so treat any precise multiple with caution.)
Fragment. A "fragment" is a defined sub-stretch of a larger protein; any retained activity has to be established experimentally. TB-500 is based on the active region of thymosin beta-4: in a preclinical assay the biological activity was concentrated in a short seven-amino-acid actin-binding motif that reproduced near-identical angiogenic activity (PMID 14500546). This establishes neither human efficacy nor safety, and TB-500 has no regulatory approval for human use. The exact length quoted for TB-500 material varies in secondary sources, so the seven-residue active motif is the sourced fact and any longer-length claim should be hedged.
1-29. As above, "GRF 1-29" and sermorelin's structure share this: sermorelin is GRF(1-29)NH2, the N-terminal 29-residue fragment of the 44-amino-acid GHRH, and the 1-29 region carries the full GH-releasing activity of the parent hormone (according to standard textbook structure-activity history).
Long R3 variant of Insulin-like Growth Factor 1, modified for reduced IGFBP binding and ~20-30 hour half-life. Researched for cell proliferation, hypertrophy, and metabolic signaling. ≥98% purity.
GHRH(1-29) analog for physiological growth hormone stimulation research
Gastric pentadecapeptide (15 amino acids) known for exceptional tissue repair properties. Promotes wound healing, angiogenesis, and cytoprotection across tendons, muscles, gut, and nerves. Over 30 years of preclinical research.
Full-length 43-amino-acid Thymosin Beta-4, a naturally occurring repair protein, independently confirmed by a third-party CoA from Janoshik. Promotes cell migration and new blood vessel formation for systemic tissue healing. Especially researched for muscle, tendon, and cardiac repair.
Salt Forms: Acetate vs Arginate vs TFA
The counterion is the part of the label people ignore, but it affects handling. Reverse-phase HPLC purification using TFA can leave a peptide as the trifluoroacetate (TFA) salt.
Why the counterion is not cosmetic (PMID 10567002)
Residual TFA, the counterion left on RP-HPLC-purified peptides, inhibited proliferation of osteoblasts and chondrocytes at 10 to the minus 8 to 10 to the minus 7 molar in a laboratory bioassay, so the authors recommend converting the peptide to hydrochloride or a biologically equivalent salt such as acetate before use in bioassays. This is a laboratory artefact finding relevant to cell-based research, not a human safety claim about injected peptides.
That is why converting to acetate or hydrochloride is recommended before bioassay work, and why a good CoA notes the salt form; acetate is one suitable alternative. Arginate is another basic counterion that shifts solubility and handling (general chemistry). The salt-form choice is handling and solubility chemistry, not an evidence-backed efficacy difference.
Albumin-anchor (DAC) vs short-acting no-DAC research
IGF-1 analogue (LR3) research
Fragment and blend research
Full-length 43-amino-acid Thymosin Beta-4, a naturally occurring repair protein, independently confirmed by a third-party CoA from Janoshik. Promotes cell migration and new blood vessel formation for systemic tissue healing. Especially researched for muscle, tendon, and cardiac repair.
The Wolverine Stack: BPC-157 + TB-500 in equal parts in one vial (50/50: 10mg = 5mg each, 20mg = 10mg each). The most researched healing peptide duo for tissue repair, tendon recovery, and systemic regeneration. Batch-specific Janoshik COA.
Research Context and Handling
CJC-1295, IGF-1 LR3, BPC-157, TB-500, sermorelin and the BPC-157/TB-500 blend are supplied for laboratory research only and are not medicines, supplements or authorised medicinal products, and are not for human or veterinary use. HGH fragment 176-191 and full-length thymosin beta-4 are named only to explain naming conventions and are not offered for sale. This article gives no dosing or preparation-for-use guidance; salt-form content is handling chemistry. Verify identity, purity and salt form against a batch-specific third-party Certificate of Analysis, and see the CJC-1295 DAC vs no-DAC detail and how peptides degrade for related handling references.
Frequently Asked Questions
This article is for research and educational purposes only. It decodes peptide nomenclature and salt-form chemistry for laboratory handling; preclinical findings are labelled as such and comparison-only compounds are not offered for sale. Nothing here is medical advice, a health claim, dosing guidance or a recommendation for use. All stocked compounds mentioned are sold exclusively for laboratory research.
Research context for English-speaking buyers
Most of our English-speaking customers ship to the UK, Ireland, Malta or other English-as-second-language EU territories. The regulatory picture differs per country.
- Relevant authorities
- MHRA (UK, post-Brexit), HPRA (Ireland, EU-aligned), FDA Section 503A bulks list (US, restricted Cat 2 status of several peptides as of 2026)
- Customs and VAT
- EU shipments include 19% VAT; UK shipments after Brexit are now extra-EU and may attract UK VAT plus a handling fee at import
- Typical shipping window
- EU 2-4 working days, UK 4-7 working days, other international 7-14 working days, depending on customs
Research-grade peptides shipped from our EU warehouse are sold for laboratory use only and are not authorised for human or veterinary therapeutic application in any of the destination jurisdictions. US customers should be aware that the FDA Section 503A bulks list classification (and the April 2026 reclassification of twelve compounds) only governs compounding pharmacies, not direct-to-researcher imports for non-clinical work. UK buyers should declare the consignment on import and may be asked for a research justification by HMRC. We provide a CoA per batch identified by colour code rather than serial number; customs sometimes asks for this document when clearing the parcel.