Learn
BPC-157
Technical Compound Reference | Orion Peptides Learning Library
BPC-157 is a synthetic linear pentadecapeptide consisting of 15 amino acid residues. The compound is identified by CAS number 137525-51-0 and has a molecular formula of C₆₂H₉₈N₁₆O₂₂.
Its sequence contains a distinctive arrangement of proline, glycine, and charged amino acid residues. These characteristics contribute to the peptide’s conformational flexibility, ionic properties, and behavior in different analytical environments.
Unlike cyclic peptides, BPC-157 does not contain a disulfide bridge or another covalent bond connecting separate regions of its backbone. Its chemical identity is defined by a continuous amino acid chain with free terminal groups.
BPC-157 is investigated using peptide chemistry, chromatographic separation, high-resolution mass spectrometry, sequence analysis, and experimental cell-signaling assays.
This reference examines the compound’s structural identity, physicochemical characteristics, analytical testing methods, chemical forms, and stability considerations.
BPC-157 Molecular Profile
| Property | Technical information |
|---|---|
| Compound name | BPC-157 |
| Alternative names | Bepecin, Body Protection Compound-157 |
| CAS number | 137525-51-0 |
| PubChem CID | 9941957 |
| Molecular formula | C₆₂H₉₈N₁₆O₂₂ |
| Average molecular weight | Approximately 1,419.5 g/mol |
| Monoisotopic neutral mass | 1,418.7042 Da |
| Amino acid count | 15 residues |
| Classification | Synthetic pentadecapeptide |
| Structural configuration | Linear |
| One-letter sequence | GEPPPGKPADDAGLV |
| N-terminal residue | Glycine |
| C-terminal residue | Valine |
| Terminal groups | Free N-terminal amine and C-terminal carboxylic acid |
| Proline residues | Four |
| Cysteine residues | None |
| Disulfide bonds | None |
| Main analytical methods | RP-HPLC, LC-MS, HRMS, peptide sequence analysis |
The molecular profile describes the reference free peptide. Acetate, trifluoroacetate, and other salt forms must be distinguished from the free-peptide structure.
1. Reading the BPC-157 Amino Acid Sequence
A peptide’s primary structure is the order in which its amino acid residues are connected.
BPC-157 contains 15 residues linked through conventional peptide bonds.
Its sequence, written from the N-terminus to the C-terminus, is:
Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val
One-letter notation:
GEPPPGKPADDAGLV
The complete free-peptide representation is:
H-Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val-OH
The H at the beginning represents the free N-terminal amino group, while OH indicates the C-terminal carboxylic acid.
Amino Acid Composition
| Residue | Symbol | Number in sequence |
|---|---|---|
| Glycine | G | 3 |
| Glutamic acid | E | 1 |
| Proline | P | 4 |
| Lysine | K | 1 |
| Alanine | A | 2 |
| Aspartic acid | D | 2 |
| Leucine | L | 1 |
| Valine | V | 1 |
| Total | 15 |
The arrangement of these residues is just as important as their total number.
Two peptides may contain the same amino acids but have different sequences and molecular properties.
Why Is Sequence Verification Important?
A molecular formula identifies the total elemental composition of a molecule.
It does not, by itself, establish the order of the amino acid residues.
A sequence variant may have the same elemental composition as the intended peptide.
For this reason, molecular mass and peptide sequence are separate analytical attributes.
2. The Unusual Proline Arrangement in BPC-157
One of BPC-157’s most recognizable structural characteristics is its proline-rich region.
Positions 3, 4, and 5 contain three consecutive proline residues.
Another proline occurs at position 8.
What Makes Proline Different?
Most standard amino acids have a relatively flexible arrangement around the backbone nitrogen.
Proline is different because its side chain forms a ring connected to that nitrogen.
This cyclic structure restricts certain backbone conformations.
Consequently, proline-rich regions often behave differently from peptide regions composed entirely of more flexible residues.
The Pro-Pro-Pro Motif
The sequence at positions 3–5 is:
Pro-Pro-Pro
Three consecutive proline residues can influence local backbone geometry and the range of conformations available to the peptide.
This does not mean the entire BPC-157 molecule has one fixed three-dimensional shape.
A linear peptide can still adopt multiple conformations depending on its environment.
Proline and Peptide Bond Isomerization
Peptide bonds adjacent to proline can show cis-trans isomerization.
Cis and trans configurations describe different arrangements around a peptide bond.
These configurations can influence local peptide structure and may contribute to conformational heterogeneity.
In analytical research, such behavior can sometimes affect chromatographic appearance.
However, additional peaks should not automatically be attributed to proline isomerization without experimental confirmation.
3. BPC-157 Has No Disulfide Bridge
BPC-157 contains no cysteine residues.
Cysteine is an amino acid with a sulfur-containing thiol group that can participate in disulfide bond formation.
Because BPC-157 lacks cysteine, its native sequence cannot form an intramolecular cysteine–cysteine disulfide bond.
This distinguishes it from peptides such as AOD-9604, which contains a defined internal disulfide bridge.
Why Does This Matter?
Disulfide-containing peptides require analytical attention to bond formation, reduction, and connectivity.
BPC-157 does not have these particular structural requirements.
However, the absence of disulfide bonds does not guarantee chemical stability.
Other degradation pathways can still affect the peptide.
Is BPC-157 a Cyclic Peptide?
No.
BPC-157 is a linear peptide.
Its proline residues contain rings within their individual amino acid structures, but those rings do not make the complete peptide backbone cyclic.
This distinction is important when describing peptide architecture.
4. Charged Residues and Molecular Behavior
BPC-157 contains several amino acids with ionizable functional groups.
These groups influence its charge and interactions with aqueous environments.
Acidic Residues
Glutamic acid occurs at position 2.
Aspartic acid occurs at positions 10 and 11.
Their side-chain carboxyl groups can lose protons under suitable conditions.
This contributes negative charge to the molecule.
Basic Residues
Lysine occurs at position 7.
Its side-chain amino group can carry a positive charge.
The free N-terminal amino group also contributes to the peptide’s acid-base behavior.
Terminal Groups
BPC-157 has a free N-terminal amino group and a free C-terminal carboxylic acid.
Both groups can participate in protonation and deprotonation equilibria.
Why pH Matters
The net charge of BPC-157 depends on the ionization state of these groups.
That state changes with pH.
As a result, the peptide’s solubility, chromatographic behavior, and interactions with surrounding molecules can vary under different conditions.
An experimental report should define the conditions under which physicochemical measurements were obtained.
5. Understanding the Molecular Mass of BPC-157
BPC-157 has the molecular formula:
C₆₂H₉₈N₁₆O₂₂
This formula describes 62 carbon atoms, 98 hydrogen atoms, 16 nitrogen atoms, and 22 oxygen atoms in the reference molecule.
Two mass-related values are particularly relevant.
Average Molecular Weight
The average molecular weight is approximately:
1,419.5 g/mol
This value is calculated using average atomic weights, which account for the natural isotopic distribution of elements.
Monoisotopic Mass
The monoisotopic neutral mass is approximately:
1,418.7042 Da
This represents the exact mass calculated using the principal isotopes of the constituent elements.
Why Are These Values Different?
Most elements exist naturally as mixtures of isotopes.
Average molecular weight incorporates isotopic abundance.
Monoisotopic mass is calculated using a specified isotopic composition.
High-resolution mass spectrometry may distinguish signals associated with different isotopes.
Therefore, analytical reports must identify which mass convention is being used.
What Does Mass Spectrometry Actually Measure?
Mass spectrometers measure the mass-to-charge ratio, written as m/z.
For a peptide, the observed signal depends on its charge state and associated ions.
A protonated peptide ion does not have exactly the same mass as the neutral peptide.
The measured signals must therefore be interpreted using the appropriate charge-state calculations.
6. Free BPC-157 vs BPC-157 Salt Forms
An important distinction in peptide chemistry is the difference between the reference free peptide and a salt-containing material.
BPC-157 contains ionizable functional groups capable of associating with counterions.
Depending on the synthesis and purification process, a preparation may contain acetate, trifluoroacetate, or another counterion.
What Is BPC-157 Acetate?
BPC-157 acetate refers to material containing BPC-157 with acetate counterions.
The amount of associated acetate can depend on the chemical preparation and the defined salt stoichiometry.
Therefore, a generic label stating “BPC-157 acetate” does not always provide enough information to calculate the complete material composition.
What Is BPC-157 TFA?
TFA stands for trifluoroacetic acid.
Trifluoroacetate may be associated with synthetic peptides prepared or purified using certain chromatographic systems.
PubChem maintains a separate chemical record for a BPC-157 form represented with two TFA molecules.
That reference has a different molecular formula and mass from the free peptide.
Why Do Salt Forms Matter?
Counterions can influence several material characteristics.
These may include total molecular composition, mass-based assay calculations, charge balance, and physicochemical behavior.
A free-peptide molecular weight should not automatically be used as the molecular weight of a separately defined salt.
Reference Comparison
| Chemical form | Formula | Reference molecular weight |
|---|---|---|
| BPC-157 free peptide | C₆₂H₉₈N₁₆O₂₂ | 1,419.5 g/mol |
| BPC-157 bis-TFA reference | C₆₆H₁₀₀F₆N₁₆O₂₆ | 1,647.6 g/mol |
| BPC-157 acetate | Depends on defined counterion stoichiometry | Material-specific |
A properly documented laboratory sample should identify its chemical form as precisely as possible.
7. Peptide Synthesis and Sequence-Related Impurities
BPC-157 can be produced through synthetic peptide chemistry.
A common approach for producing defined peptide sequences is solid-phase peptide synthesis, abbreviated SPPS.
In SPPS, amino acid residues are added sequentially to a growing peptide chain attached to a solid support.
After synthesis, the peptide is separated from the support and processed for purification and characterization.
Why Can Sequence-Related Impurities Occur?
Peptide synthesis involves multiple chemical reactions.
Incomplete reactions or unwanted side reactions can produce molecules that differ from the intended sequence.
Potential impurity categories include:
- Deletion sequences
- Truncated peptides
- Incompletely deprotected material
- Chemically modified residues
- Process-related residual substances
The actual impurity profile must be established experimentally.
Are All Impurities Detectable Through One Method?
No.
Different impurities can have different chemical and analytical properties.
Some may be separated using reversed-phase HPLC.
Others may require mass spectrometry or complementary techniques.
A single chromatographic method does not necessarily detect every impurity.
8. Analytical Identification: HPLC and Mass Spectrometry
Reliable peptide characterization requires more than matching a compound name with a molecular formula.
A laboratory may need to verify that the actual material is consistent with the intended 15-residue BPC-157 structure.
Reversed-Phase High-Performance Liquid Chromatography
RP-HPLC separates sample components according to their interactions with the chromatographic stationary and mobile phases.
It is commonly used to assess synthetic peptide purity.
A BPC-157 chromatogram may show a principal peak associated with the intended peptide and additional peaks corresponding to detectable related substances.
What Does HPLC Purity Mean?
HPLC purity is usually reported as a percentage derived from chromatographic measurements.
Its interpretation depends on the analytical conditions and calculation method.
A result of 99% HPLC purity does not necessarily mean that 99% of the total physical sample mass is pure BPC-157.
Other substances may not be fully represented by the chromatographic measurement.
Electrospray Ionization Mass Spectrometry
Electrospray ionization, or ESI, can convert peptides into gas-phase ions for mass spectrometric analysis.
Because BPC-157 contains ionizable groups, it may produce ions with different charge states.
The observed mass-to-charge signals can be compared with those predicted from its molecular formula.
High-Resolution Mass Spectrometry
High-resolution mass spectrometry provides more precise mass measurements.
Accurate-mass data can help distinguish some molecular species with similar nominal masses.
However, even a highly accurate mass measurement does not conclusively establish the complete amino acid sequence.
Why LC-MS Can Be Useful
Liquid chromatography-mass spectrometry combines chromatographic separation with mass analysis.
The method can associate mass-related information with individual chromatographic peaks.
This is particularly useful when examining impurities or chemically modified peptide species.
Analytical Methods Compared
| Technique | Information provided |
|---|---|
| RP-HPLC | Chromatographic separation and purity-related findings |
| ESI-MS | Molecular mass-to-charge information |
| HRMS | High-accuracy molecular mass evidence |
| LC-MS | Mass analysis of separated components |
| LC-MS/MS | Additional sequence and fragmentation information |
| Amino acid analysis | Information about residue composition |
| Quantitative assay | Peptide amount under a defined method |
Each method provides a different kind of evidence.
Analytical quality is stronger when several suitable methods support the same material identity.
9. What Mass Spectrometry Reveals About BPC-157 Fragments
Fragmentation techniques can provide additional information about peptide structure.
In tandem mass spectrometry, selected peptide ions are fragmented and the resulting compound ions are analyzed.
The fragmentation pattern can provide clues about amino acid sequence.
What Are b- and y-Ions?
In peptide mass spectrometry, b-ions and y-ions are commonly observed compound-ion families.
They are associated with cleavage of peptide backbone bonds.
A series of suitable fragments can support the identification of a peptide sequence.
Can LC-MS/MS Verify BPC-157?
LC-MS/MS can provide stronger sequence-related evidence than intact mass alone.
However, the completeness of sequence confirmation depends on the quality and coverage of the fragmentation data.
A result should be described according to what was actually measured.
Published Analytical Research
A 2023 study published in Molecules used stable-isotope labeling and UHPLC-high-resolution mass spectrometry to investigate BPC-157’s in-vitro metabolic profile.
The study illustrates the use of advanced analytical methods for distinguishing peptide-related molecular species.
The research is particularly relevant to understanding metabolite identification and mass-spectrometric interpretation.
Related scientific paper: https://pmc.ncbi.nlm.nih.gov/articles/PMC10650108/
10. Physicochemical Stability and Degradation
Chemical stability describes whether a substance retains its specified chemical characteristics under defined conditions.
BPC-157 contains multiple peptide bonds, acidic and basic functional groups, and a proline-rich sequence.
These structural characteristics are relevant when assessing stability.
Chemical Degradation
Potential degradation processes may include peptide bond hydrolysis and reactions affecting susceptible side-chain groups.
The actual pathways depend on the chemical environment.
Physical Changes
Physical stability refers to changes that do not necessarily alter the peptide’s primary covalent sequence.
These can include aggregation, adsorption to surfaces, or changes in molecular association.
What Factors Influence Stability?
Important variables include temperature, moisture, pH, buffer composition, oxygen exposure, and storage duration.
Does BPC-157 Have a Fixed Shelf Life?
No universal shelf life can be assigned to every BPC-157 research preparation.
Shelf-life claims require stability studies performed on the specific material and formulation.
Why Is a Clear Solution Not Enough?
Visual clarity does not confirm molecular identity, chemical purity, or the absence of soluble degradation compounds.
Analytical testing provides more reliable evidence of chemical condition than appearance alone.
11. Why BPC-157 Has No Universally Established Receptor Assay
Some peptides have a clearly established primary receptor.
For example, Sermorelin acts through the growth hormone-releasing hormone receptor.
BPC-157 is different.
Although preclinical studies have reported changes in several signaling pathways, a single primary receptor has not been conclusively established.
What Does This Mean for Laboratory Research?
A receptor-based potency assay requires a well-defined molecular target and measurable signaling response.
Without a confirmed primary receptor, it is more difficult to establish a single standard functional assay for BPC-157.
Proposed Signaling Pathways
Experimental publications have investigated pathways involving:
- Focal adhesion kinase (FAK)
- Paxillin
- VEGFR2-related signaling
- Akt-related signaling
- Nitric oxide-associated pathways
These are proposed or observed relationships in specific experimental systems.
They should not all be described as direct molecular targets of BPC-157.
Identity vs Biological Activity
A sample may be chemically consistent with the expected BPC-157 sequence without having undergone a functional biological assay.
Conversely, a biological response in a cell model does not by itself establish complete chemical identity.
The two types of characterization address different questions.
Related Orion research: https://orionpeptide.com/bpc-157-and-connective-tissue-remodeling/
12. How to Read a BPC-157 Certificate of Analysis
A Certificate of Analysis records test results associated with a particular sample or batch.
A well-documented BPC-157 COA should distinguish the theoretical reference structure from actual analytical findings.
Important Fields
| COA field | Technical purpose |
|---|---|
| Compound name | Identifies the material being analyzed |
| CAS number | Provides chemical reference information |
| Batch number | Connects results to a specific sample |
| Chemical form | Identifies free peptide or defined salt form |
| Expected molecular mass | Reference for MS interpretation |
| Observed molecular mass | Reports measured mass-related findings |
| HPLC chromatogram | Displays the separation profile |
| HPLC purity | Reports chromatographic purity under the test method |
| Peptide content | Provides quantitative assay information, if measured |
| Counterion content | Identifies associated counterions, if tested |
| Water content | Reports residual moisture, if measured |
| Testing date | Documents when the analysis occurred |
| Laboratory identification | Identifies the testing organization |
Why Is a Lot-Matched COA Important?
Peptide batches may differ in impurity profiles or material composition.
Results associated with one production batch cannot automatically establish the properties of another.
A lot-matched report provides better traceability.
Can a COA Guarantee Every Quality Attribute?
No.
A COA establishes only what the documented analytical methods actually measured.
For example, HPLC purity does not independently establish peptide content, sterility, or all possible chemical impurities.
13. BPC-157 in Multi-Peptide Research Formulations
BPC-157 also appears as a component in commercially defined research mixtures.
Examples include GLOW and KLOW.
GLOW
GLOW commonly contains BPC-157, GHK-Cu, and TB-500-related material.
KLOW
KLOW contains BPC-157, GHK-Cu, TB-500, and KPV.
Why Must the Components Be Analyzed Separately?
A mixture does not have one universal amino acid sequence or molecular weight.
Each component retains its own molecular identity.
The presence of several peptides also introduces analytical challenges related to separation, component quantification, and chemical compatibility.
Research on individual BPC-157 does not automatically characterize its behavior within GLOW or KLOW.
Related Orion research: https://orionpeptide.com/klow-peptide-composition/
14. Frequently Asked Technical Questions About BPC-157
What is BPC-157?
BPC-157 is a synthetic linear peptide composed of 15 amino acid residues.
What is its amino acid sequence?
GEPPPGKPADDAGLV.
What is the molecular formula of BPC-157?
C₆₂H₉₈N₁₆O₂₂.
What is the molecular weight of BPC-157?
Approximately 1,419.5 g/mol for the free peptide.
What is the monoisotopic mass?
Approximately 1,418.7042 Da for the neutral free peptide.
What is the CAS number?
137525-51-0.
What is the PubChem CID?
Is BPC-157 a cyclic peptide?
No. It has a linear peptide backbone.
Does BPC-157 contain disulfide bonds?
No. Its sequence contains no cysteine residues.
How many proline residues does BPC-157 contain?
Four.
What is unusual about its proline sequence?
It contains three consecutive proline residues at positions 3–5.
Does BPC-157 have a free C-terminus?
Yes. The reference peptide has a C-terminal carboxylic acid.
Is BPC-157 acetate the same chemical form as the free peptide?
No. Acetate material contains counterions associated with the peptide.
What is BPC-157 TFA?
It is a trifluoroacetate-containing form of the peptide.
Why can BPC-157 salt forms have different masses?
Counterions contribute additional chemical components and mass.
Does HPLC identify the peptide sequence?
HPLC primarily provides chromatographic separation information. Additional analytical methods may be required for sequence characterization.
Can mass spectrometry confirm molecular identity?
Mass spectrometry can support identity by providing molecular mass evidence.
What is the difference between average and monoisotopic mass?
Average mass considers natural isotopic abundances, while monoisotopic mass uses a defined isotope composition.
What is LC-MS/MS?
It is a technique combining chromatographic separation with tandem mass spectrometry to investigate molecular and structural characteristics.
Does BPC-157 have a confirmed primary receptor?
No single primary receptor has been conclusively established.
Does 99% HPLC purity mean 99% peptide content?
No. They are different analytical measurements.
Can BPC-157 undergo degradation?
Yes. Chemical and physical changes can occur under different environmental conditions.
What is a BPC-157 COA?
A Certificate of Analysis records specified tests performed on a particular sample or batch.
Is BPC-157 FDA-approved?
No. BPC-157 is not an FDA-approved drug substance.
15. Scientific References and Technical Resources
PubChem: BPC-157
Compound CID: 9941957
Reference information: Molecular formula, molecular weight, exact mass, CAS number, and amino acid sequence.
PubChem: BPC-157 TFA Salt
Compound CID: 172966211
Reference information: Chemical composition and molecular weight of the bis-trifluoroacetate reference.
BPC-157 High-Resolution Mass Spectrometry Research
Stable Isotope Labeling-Based Nontargeted Strategy for Characterization of the In Vitro Metabolic Profile of a Novel Doping BPC-157 in Doping Control by UHPLC-HRMS (2023)
Journal: Molecules
Research relevance: High-resolution mass spectrometry, metabolite identification, stable-isotope labeling, and analytical characterization.
BPC-157 Analytical Development Review
BPC-157 as an Investigational Peptide Therapeutic: Biopharmaceutical Challenges, Formulation Strategies, and Translational Development Barriers (2026)
Research relevance: Peptide characterization, assay development, chromatographic analysis, and formulation-related technical uncertainties.
FDA Chemical and Safety Reference
Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks
Reference information: FDA’s published assessment of selected peptide substances, including BPC-157.
Conclusion
BPC-157 is a synthetic pentadecapeptide defined by a 15-residue linear amino acid sequence.
Its chemical structure contains a distinctive proline-rich region, several ionizable amino acid groups, and free terminal functional groups.
Unlike disulfide-containing or cyclic peptides, BPC-157 does not require characterization of cysteine connectivity or backbone cyclization.
However, accurate molecular identification still requires careful interpretation of peptide sequence, molecular mass, chemical form, chromatographic purity, and batch-specific analytical results.
Its physicochemical properties and stability depend on the material and the experimental environment.
For scientific characterization, HPLC, mass spectrometry, and complementary analytical techniques provide different but useful information about the compound.
A technically reliable reference should therefore distinguish theoretical molecular properties from measured characteristics of an individual laboratory sample.
Technical research notice: This article is intended for scientific education and laboratory reference. It does not provide dosing, reconstitution, administration, or medical-use instructions. BPC-157 is not FDA-approved, and analytical characterization does not establish the suitability of a research material for human or veterinary use.
