Common Peptide Abbreviations & Acronyms
Peptide science has its own language. Open any research paper, skim a compounding pharmacy catalog, or browse a clinical trial listing, and you'll run into a wall of abbreviations — GHRP, SPPS, DPP-4, SC, Fmoc. This guide decodes them all.
Peptide science has its own language. Open any research paper, skim a compounding pharmacy catalog, or browse a clinical trial listing, and you'll run into a wall of abbreviations — GHRP, SPPS, DPP-4, SC, Fmoc. This guide decodes them all.
Below you'll find an alphabetical reference covering amino acid codes, peptide categories, synthesis techniques, analytical methods, regulatory terms, and clinical abbreviations. Whether you're reading a certificate of analysis or parsing a PubMed abstract, this is the glossary you need.
Table of Contents
- Amino Acid Abbreviations
- Peptide Categories and Types
- Synthesis and Manufacturing
- Analytical and Quality Control
- Pharmacology and Clinical Terms
- Regulatory and Industry Terms
- Routes of Administration
- FAQ
- The Bottom Line
- References
Amino Acid Abbreviations
The 20 standard amino acids have both a three-letter code and a single-letter code, standardized by the IUPAC-IUB Joint Commission on Biochemical Nomenclature. You'll see these everywhere — from peptide sequence descriptions to product labels.
Standard Amino Acids
| Amino Acid | Three-Letter Code | One-Letter Code |
|---|---|---|
| Alanine | Ala | A |
| Arginine | Arg | R |
| Asparagine | Asn | N |
| Aspartic acid | Asp | D |
| Cysteine | Cys | C |
| Glutamic acid | Glu | E |
| Glutamine | Gln | Q |
| Glycine | Gly | G |
| Histidine | His | H |
| Isoleucine | Ile | I |
| Leucine | Leu | L |
| Lysine | Lys | K |
| Methionine | Met | M |
| Phenylalanine | Phe | F |
| Proline | Pro | P |
| Serine | Ser | S |
| Threonine | Thr | T |
| Tryptophan | Trp | W |
| Tyrosine | Tyr | Y |
| Valine | Val | V |
Special Codes and Non-Standard Amino Acids
| Code | Three-Letter | Meaning |
|---|---|---|
| B | Asx | Asparagine or Aspartic acid (ambiguous) |
| Z | Glx | Glutamine or Glutamic acid (ambiguous) |
| X | Xaa | Any amino acid / unknown |
| J | Xle | Leucine or Isoleucine (ambiguous) |
| U | Sec | Selenocysteine (21st amino acid) |
| O | Pyl | Pyrrolysine (22nd amino acid) |
A quick memory trick: most three-letter codes are the first three letters of the amino acid name (Ala, Arg, Gly, etc.). The exceptions — Asn, Gln, Trp, and Ile — are shortened differently to avoid confusion with similar names (Asp/Asn, Glu/Gln) or because the first three letters weren't distinctive enough.
For more on peptide structure basics, see What Are Peptides: The Complete Beginner's Guide.
Peptide Categories and Types
By Function
| Abbreviation | Full Term | Definition |
|---|---|---|
| AMP | Antimicrobial Peptide | Peptides that kill or inhibit bacteria, fungi, or viruses. Also called host defense peptides (HDP). Examples: LL-37, defensins |
| BNP | B-type Natriuretic Peptide | Cardiac peptide hormone released by ventricles in response to volume overload. Used as a heart failure biomarker |
| ANP | Atrial Natriuretic Peptide | Peptide hormone released by atrial cardiomyocytes in response to stretching |
| CPP | Cell-Penetrating Peptide | Short peptides that facilitate cellular uptake of molecular cargo across membranes |
| GIP | Glucose-dependent Insulinotropic Polypeptide (formerly Gastric Inhibitory Polypeptide) | Incretin hormone that stimulates insulin release. Target of tirzepatide |
| GLP-1 | Glucagon-Like Peptide-1 | Incretin hormone that stimulates insulin, suppresses glucagon, and slows gastric emptying. Basis for semaglutide, liraglutide |
| GLP-2 | Glucagon-Like Peptide-2 | Peptide hormone that promotes intestinal mucosal growth. Basis for teduglutide (Gattex) |
| GHRH | Growth Hormone-Releasing Hormone | Hypothalamic peptide that stimulates GH release from the pituitary. Basis for sermorelin, tesamorelin, CJC-1295 |
| GHRP | Growth Hormone-Releasing Peptide | Synthetic peptides that stimulate GH via the ghrelin receptor. Includes GHRP-2, GHRP-6, hexarelin, ipamorelin |
| GHS | Growth Hormone Secretagogue | Broad category including GHRPs and non-peptide agents like MK-677 that stimulate GH release |
| GnRH | Gonadotropin-Releasing Hormone | Hypothalamic peptide controlling reproductive hormones. Also called LHRH |
| HDP | Host Defense Peptide | Alternative name for antimicrobial peptides, reflecting their broader immunomodulatory roles |
| LHRH | Luteinizing Hormone-Releasing Hormone | Older name for GnRH |
| MSH | Melanocyte-Stimulating Hormone | Peptide hormones (alpha, beta, gamma) that regulate melanin production |
| NPY | Neuropeptide Y | One of the most abundant peptides in the central nervous system, involved in appetite, anxiety, and stress |
| PDC | Peptide-Drug Conjugate | Peptide attached to a cytotoxic agent for targeted cancer therapy |
| POMC | Pro-opiomelanocortin | Large precursor peptide processed into ACTH, MSH, beta-endorphin |
| VIP | Vasoactive Intestinal Peptide | Neuropeptide with roles in vasodilation, immune modulation, and circadian rhythm |
By Structure
| Abbreviation | Full Term | Definition |
|---|---|---|
| BPC | Body Protection Compound | Refers to BPC-157, a 15-amino-acid peptide from gastric juice |
| DAC | Drug Affinity Complex | Maleimide linker enabling covalent albumin binding; used in CJC-1295 with DAC to extend half-life |
| MDP | Mitochondria-Derived Peptide | Peptides encoded by mitochondrial DNA, such as humanin and MOTS-c |
| RGD | Arginine-Glycine-Aspartic acid | Tripeptide motif recognized by integrins; used in cell adhesion research |
Synthesis and Manufacturing
| Abbreviation | Full Term | Definition |
|---|---|---|
| SPPS | Solid-Phase Peptide Synthesis | Method where the peptide chain is assembled on an insoluble resin support, one amino acid at a time. Invented by Robert Bruce Merrifield in 1963 (Nobel Prize, 1984) |
| LPPS | Liquid-Phase Peptide Synthesis | Classical solution-phase synthesis; still used for some short peptides and large-scale manufacturing |
| Fmoc | 9-Fluorenylmethyloxycarbonyl | Base-labile protecting group for the amino terminus; dominant strategy in modern SPPS (Fmoc/tBu) |
| Boc | tert-Butyloxycarbonyl | Acid-labile amino-terminal protecting group; used in Boc/Bzl SPPS strategy |
| tBu | tert-Butyl | Side-chain protecting group used in Fmoc SPPS |
| Bzl | Benzyl | Side-chain protecting group used in Boc SPPS |
| Cbz (or Z) | Carboxybenzyl (or Benzyloxycarbonyl) | The first amino-protecting group used in peptide synthesis (Bergmann and Zervas, 1932) |
| DIC | N,N'-Diisopropylcarbodiimide | Coupling reagent used to form peptide bonds during SPPS |
| DIEA | N,N-Diisopropylethylamine | Base commonly used in Fmoc SPPS coupling steps |
| DMF | Dimethylformamide | Primary solvent used in Fmoc SPPS |
| HATU | Hexafluorophosphate Azabenzotriazole Tetramethyl Uronium | High-efficiency coupling reagent for difficult sequences |
| HBTU | Hexafluorophosphate Benzotriazole Tetramethyl Uronium | Common coupling reagent in SPPS |
| HOBt | Hydroxybenzotriazole | Additive that suppresses racemization during coupling |
| NMP | N-Methyl-2-pyrrolidone | Alternative SPPS solvent |
| PEG | Polyethylene Glycol | Polymer conjugated to peptides (PEGylation) to increase molecular size and half-life |
| rDNA | Recombinant DNA | Technology used to produce peptides and proteins in living cells (E. coli, yeast, CHO cells) |
| TFA | Trifluoroacetic Acid | Acid used for final cleavage of peptides from resin in Fmoc SPPS and for global side-chain deprotection |
| GMP | Good Manufacturing Practice | Quality standards required for pharmaceutical-grade peptide production |
| cGMP | Current Good Manufacturing Practice | FDA-enforced GMP standards that evolve with technology |
Analytical and Quality Control
| Abbreviation | Full Term | Definition |
|---|---|---|
| HPLC | High-Performance Liquid Chromatography | Primary method for peptide purification and purity assessment. A peptide's HPLC purity percentage (e.g., >98%) is the standard quality metric |
| RP-HPLC | Reversed-Phase HPLC | The most common HPLC mode for peptides, separating by hydrophobicity |
| UPLC | Ultra-Performance Liquid Chromatography | Faster, higher-resolution version of HPLC |
| MS | Mass Spectrometry | Measures molecular mass to confirm peptide identity |
| ESI-MS | Electrospray Ionization Mass Spectrometry | Soft ionization technique ideal for peptide mass measurement |
| MALDI-TOF | Matrix-Assisted Laser Desorption/Ionization Time-of-Flight | Mass spec method for larger peptides and proteins |
| LC-MS | Liquid Chromatography-Mass Spectrometry | Combined technique for peptide identification and quantification |
| LC-MS/MS | Tandem Mass Spectrometry | Sequential mass analysis for peptide sequencing and trace detection |
| CoA | Certificate of Analysis | Document reporting peptide identity, purity, and quality test results |
| MW | Molecular Weight | Mass of a peptide, typically in Daltons (Da) or kilodaltons (kDa) |
| AA | Amino Acid | Building block of peptides |
| CD | Circular Dichroism | Spectroscopic method to determine peptide secondary structure |
| NMR | Nuclear Magnetic Resonance | Spectroscopy used for 3D peptide structure determination |
| LAL | Limulus Amebocyte Lysate | Endotoxin testing assay required for injectable peptides |
| USP | United States Pharmacopeia | Compendium of drug quality standards |
For a deeper look at analytical methods, see Understanding Peptide Purity: HPLC and Mass Spec.
Pharmacology and Clinical Terms
| Abbreviation | Full Term | Definition |
|---|---|---|
| t1/2 | Half-life | Time for plasma concentration to decrease by 50% |
| PK | Pharmacokinetics | How the body absorbs, distributes, metabolizes, and eliminates a drug |
| PD | Pharmacodynamics | What the drug does to the body (mechanism and effects) |
| ADME | Absorption, Distribution, Metabolism, Excretion | The four processes governing a drug's journey through the body |
| AUC | Area Under the Curve | Total drug exposure over time; a key PK parameter |
| Cmax | Maximum Concentration | Peak plasma drug level after dosing |
| Tmax | Time to Maximum Concentration | Time from dosing to peak plasma level |
| Vd | Volume of Distribution | Theoretical volume needed to contain the total drug at plasma concentration |
| CL | Clearance | Volume of plasma cleared of drug per unit time |
| Css | Steady-State Concentration | Stable drug level achieved when intake equals elimination |
| SC | Subcutaneous | Injection beneath the skin into fatty tissue — the most common route for peptide drugs |
| IM | Intramuscular | Injection into muscle tissue |
| IV | Intravenous | Injection directly into a vein |
| IN | Intranasal | Administration through the nasal mucosa |
| DPP-4 | Dipeptidyl Peptidase-4 | Enzyme that rapidly degrades native GLP-1 and GIP (t1/2 ~2 min). DPP-4 inhibitors (gliptins) are a separate drug class from GLP-1 agonists |
| NEP | Neprilysin | Enzyme that degrades natriuretic peptides, substance P, and other peptides |
| ACE | Angiotensin-Converting Enzyme | Enzyme that converts angiotensin I to angiotensin II; target of ACE inhibitors |
| GFR | Glomerular Filtration Rate | Kidney filtration rate; peptides below ~60 kDa are renally filtered |
| IGF-1 | Insulin-Like Growth Factor 1 | Growth factor stimulated by GH; mediates many of GH's effects |
| GH | Growth Hormone | 191-amino-acid protein (somatotropin) released from the pituitary |
| hGH | Human Growth Hormone | Specifically human GH, distinguished from animal forms |
| rhGH | Recombinant Human Growth Hormone | Synthetically produced hGH (e.g., somatropin) |
| ACTH | Adrenocorticotropic Hormone | 39-amino-acid pituitary peptide that stimulates cortisol release |
| ADH | Antidiuretic Hormone | Vasopressin; regulates water balance |
| BMI | Body Mass Index | Weight-to-height ratio used in obesity treatment trials |
| HbA1c | Glycated Hemoglobin | 3-month average blood sugar marker; primary endpoint in diabetes trials |
| T2DM | Type 2 Diabetes Mellitus | Metabolic disease characterized by insulin resistance |
| HSDD | Hypoactive Sexual Desire Disorder | Condition treated by bremelanotide/PT-141 |
For half-life data on specific peptides, see our Peptide Half-Life Chart.
Regulatory and Industry Terms
| Abbreviation | Full Term | Definition |
|---|---|---|
| FDA | Food and Drug Administration | U.S. agency regulating drugs and biologics |
| EMA | European Medicines Agency | European regulatory authority for medicinal products |
| CDER | Center for Drug Evaluation and Research | FDA division reviewing most peptide drugs |
| CBER | Center for Biologics Evaluation and Research | FDA division reviewing biological products (proteins >40 amino acids) |
| NDA | New Drug Application | Approval pathway for small molecules and peptides (<=40 amino acids) |
| BLA | Biologics License Application | Approval pathway for biological products (>40 amino acids, including insulin since 2020) |
| ANDA | Abbreviated New Drug Application | Pathway for generic versions of NDA-approved drugs |
| 503A | Section 503A of the FD&C Act | Governs traditional (patient-specific) pharmacy compounding |
| 503B | Section 503B of the FD&C Act | Governs outsourcing facility compounding (can compound without patient-specific prescriptions) |
| IND | Investigational New Drug | FDA application required before testing an unapproved drug in humans |
| ICH | International Council for Harmonisation | Organization that sets global pharmaceutical quality guidelines |
| GLP | Good Laboratory Practice | Quality standards for non-clinical safety studies (not to be confused with GLP-1) |
| GCP | Good Clinical Practice | Ethical and scientific quality standards for clinical trials |
| WADA | World Anti-Doping Agency | International organization that maintains the prohibited substances list for sports |
| RUO | Research Use Only | Label indicating a compound is sold for laboratory research, not human use |
| DSHEA | Dietary Supplement Health and Education Act | 1994 U.S. law governing supplement regulation |
| GRAS | Generally Recognized as Safe | FDA designation for food substances (not applicable to injectable peptides) |
| DEA | Drug Enforcement Administration | U.S. agency that regulates controlled substances (some peptide-related compounds may fall under DEA scheduling) |
| OTC | Over the Counter | Drugs available without a prescription |
| Rx | Prescription | Medications requiring a physician's order |
| USP | United States Pharmacopeia | Compendium of drug quality standards |
| EP | European Pharmacopoeia | European equivalent of USP |
| API | Active Pharmaceutical Ingredient | The pharmacologically active component of a drug product |
For more on regulatory pathways, see our FDA-Approved Peptide Drug List and our guide to peptide legality.
Routes of Administration
These abbreviations appear frequently in prescribing information and research papers.
| Abbreviation | Full Term | Notes |
|---|---|---|
| PO | Per os (oral) | By mouth; rare for peptides due to GI degradation |
| SC / SQ / SubQ | Subcutaneous | Most common peptide injection route |
| IM | Intramuscular | Used for some depot formulations |
| IV | Intravenous | Direct bloodstream delivery; used in hospital settings |
| IN | Intranasal | Used for oxytocin, desmopressin, semax, selank |
| IT | Intrathecal | Into spinal fluid; rare, for CNS-targeted peptides |
| IP | Intraperitoneal | Common in animal studies, rare in human use |
| TD | Transdermal | Through the skin; limited for peptides due to size |
| SL | Sublingual | Under the tongue; explored for some small peptides |
| PR | Per rectum (rectal) | Rarely used for peptides |
| TOP | Topical | Applied to the skin surface; used for cosmetic peptides like GHK-Cu |
FAQ
What's the difference between GLP-1 and a GLP-1 agonist?
GLP-1 (glucagon-like peptide-1) is the natural hormone your gut produces after eating. It lasts about 2 minutes before DPP-4 breaks it down. A GLP-1 agonist (like semaglutide or liraglutide) is a synthetic molecule engineered to activate the same receptor but resist degradation, lasting hours to days instead of minutes. The abbreviation "GLP-1 RA" stands for GLP-1 Receptor Agonist.
What does SPPS mean and why does it matter?
SPPS stands for Solid-Phase Peptide Synthesis, the manufacturing method behind virtually every research and therapeutic peptide produced today. Before Robert Merrifield invented it in 1963, synthesizing even a short peptide could take months or years. SPPS made it possible to build peptides one amino acid at a time on a resin support, with each step automated. This is why peptides went from laboratory curiosities to a $49 billion therapeutic market.
Why do some peptide drugs get approved through an NDA and others through a BLA?
In the U.S., the dividing line is 40 amino acids. Peptides with 40 or fewer amino acids are regulated as drugs (NDA pathway, reviewed by CDER). Larger peptides and proteins go through the biologics pathway (BLA, sometimes reviewed by CBER). In 2020, even insulin (51 amino acids) was reclassified from NDA to BLA. This distinction matters for patent exclusivity, generic competition, and manufacturing requirements.
What do the numbers after GHRP mean (GHRP-2, GHRP-6)?
The numbers are simply designations assigned during development — they don't indicate potency, generation, or amino acid count. GHRP-6 was actually developed before GHRP-2. GHRP-1 was the first in the series (a heptapeptide), while GHRP-2 and GHRP-6 are hexapeptides with different selectivity profiles. The "6" in GHRP-6 refers to its position in the development sequence, not its structure.
What's the difference between RUO (Research Use Only) and pharmaceutical-grade peptides?
RUO peptides are manufactured and sold for laboratory research only — not for human use. They may have lower purity standards, less rigorous testing, and no GMP manufacturing oversight. Pharmaceutical-grade peptides are produced under cGMP conditions, undergo full quality testing (identity, purity, potency, sterility, endotoxin levels), and are approved for human administration. The gap between these two categories is one reason regulatory agencies have raised concerns about the use of research-grade peptides in clinical settings.
The Bottom Line
Peptide science spans biochemistry, pharmacology, manufacturing, and regulation — and each field brings its own shorthand. This reference covers the abbreviations you're most likely to encounter when reading research papers, talking to healthcare providers, or evaluating peptide products. Bookmark it and come back when you hit an unfamiliar acronym.
For definitions of peptide-specific terms beyond abbreviations, see our Peptide Glossary: A-Z Terminology Guide.
References
- IUPAC-IUB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides." Pure and Applied Chemistry. 1984;56(5):595-624.
- Bachem. "List of Abbreviations." bachem.com
- Antimicrobial Peptide Database. "Glossary." University of Nebraska Medical Center. aps.unmc.edu
- AAPTec. "Abbreviations and Their Meanings." peptide.com
- Merrifield RB. "Solid Phase Peptide Synthesis. I. The Synthesis of a Tetrapeptide." Journal of the American Chemical Society. 1963;85(14):2149-2154.
- FDA. "Deemed to be a License — Biological Product." Guidance Documents. FDA.gov
- Peptide Glossary: A-Z Terminology Guide — PeptideJournal.org internal reference
- What Are Peptides: The Complete Beginner's Guide — PeptideJournal.org