BPC-157 Arginate (Pentadeca Arginate / PDA)
Two numbers dominate every page written about BPC-157 arginate: around 90% oral bioavailability, and 1,000 times more stable than acetate. Both are repeated without citation almost everywhere they appear. This page traces each of them back to its primary document, reproduces the underlying data, and states plainly which one has a source and which one does not.
This research format is not currently listed. Contact the lab desk for availability.
For the general oral format, the per-oral rat literature and the state of the human evidence, see BPC-157 capsules, oral research formats.
1. The peptide is identical in both salt forms
BPC-157 is the pentadecapeptide GEPPPGKPADDAGLV. As a free peptide its molecular weight is 1419.53 g/mol. Neither arginate nor acetate changes that sequence or that molecule. The words describe the counter-ion supplied alongside the peptide in the isolated salt, nothing more.
The two counter-ions sit at opposite ends of the molecule. Acetate is an anion, so it pairs with the basic sites: the lysine side chain and the free N-terminus. Arginine is a cation, so it pairs with the acidic sites: the two aspartate residues and the C-terminal carboxyl. The patent that underpins the arginate claims specifies a di-L-arginine salt, that is, two arginine counter-ions per peptide.
This is why pentadeca arginate is not a new compound. It is a salt selection decision applied to a peptide that has been in the literature since the 1990s.
2. Net peptide content by salt form
Counter-ions have mass, and that mass is included when material is weighed out. The heavier the counter-ion, the less of each milligram is peptide. This is the practical consequence of salt choice, and it is measurable rather than claimed.
| Form | Molecular weight | Peptide content |
|---|---|---|
| Free peptide | 1419.5 | 100% |
| Mono-acetate | 1479.6 | ~95.9% |
| Di-acetate | 1539.6 | ~92.2% |
| Mono-arginate | 1593.7 | ~89.1% |
| Di-arginate | 1767.9 | ~80.3% |
Stated plainly: a 5 mg di-arginate presentation contains roughly 4.0 mg of actual BPC-157, against roughly 4.6 to 4.8 mg for acetate forms. That is a shortfall of about 15 to 19% of peptide per milligram of material, before any question of stability or absorption is raised.
Important qualifier: real salt stoichiometry is rarely exactly mono or di, and residual water content varies batch to batch. Treat the table as the arithmetic ceiling, not as a measurement. Net peptide content should be read from the batch certificate of analysis, not calculated.
3. The stability data has a real source
The gastric stability claims are not invented. They come from US Patent 9,850,282 B2, assigned to Diagen d.o.o., inventor Rudolf Rucman, priority date 13 March 2013, granted 26 December 2017. The patent reports stability of BPC-157 salts in gastric juice at pH 3.0 and 37 °C, expressed as percentage of peptide remaining intact.
| Salt form | 0.5 h | 1 h | 5 h |
|---|---|---|---|
| BPC acetate | 41.7% | 26.1% | 0.08% |
| BPC sodium salt | 81.9% | 71.6% | 10.1% |
| Arg-BPC (arginate) | 98.1% | 96.5% | 84.9% |
Caveat, stated clearly: this is patent data. It was filed by a commercial party with an interest in the outcome, it has not been peer-reviewed, and no independent laboratory has published a replication. It is the best available source for the claim, and it is a weak one.
4. Where 1,000 times more stable comes from
Take the 5 hour column above. 84.9% intact for the arginate, 0.08% for the acetate. Divide one by the other: 84.9 ÷ 0.08 ≈ 1,061.
That is the whole derivation. The 1,000x figure is a single ratio taken from a single row of a single patent table, and it describes survival in simulated gastric juice at one pH and one temperature. It is not a general statement about the stability of the molecule, and it carries every limitation of its source.
5. Where 90% bioavailability comes from
The patent contains no bioavailability figure of any kind. The number 90% does not appear in it.
The most probable reconstruction, and this is offered explicitly as inference rather than as fact: the gastric-survival percentages, 96.5% intact at 1 hour and 84.9% at 5 hours, were restated as oral bioavailability above 90%. That figure was then welded to a contrasting under 3%, which is the generic textbook figure for the oral bioavailability of unmodified peptides in general, not a measurement of BPC-157 acetate. The pairing reads as a study result. It is two unrelated numbers placed next to each other.
Surviving the stomach is not the same as being absorbed.
These are two different hurdles. Gastric stability determines how much intact peptide reaches the small intestine. Bioavailability is governed by what crosses the intestinal epithelium and survives first-pass metabolism, and a 1,419 dalton peptide with fifteen residues faces that barrier regardless of which counter-ion accompanied it into the gut. No counter-ion addresses epithelial permeability. A stability percentage cannot be converted into a bioavailability percentage.
6. The measurement that settles it
He et al., 2022, in Frontiers in Pharmacology (PMID 36588717, DOI 10.3389/fphar.2022.1026182) measured the absolute bioavailability of BPC-157 by the intramuscular route. In rats it was 14 to 19%. In dogs it was 45 to 51%. Elimination half-life was under 30 minutes in both species.
Intramuscular injection bypasses the gut entirely, and in rats it still reached only 14 to 19%. An oral figure above that, let alone one near 90%, is not plausible without new data, and no such data exists for any salt form.
7. The sodium salt result undercuts arginine specificity
Look again at the patent table. The sodium salt also vastly outperformed the acetate: 71.6% intact at 1 hour and 10.1% at 5 hours, against 26.1% and 0.08%. If a simple inorganic counter-ion produces a large part of the same effect, then any mechanism proposed as unique to arginine, whether nitric oxide pathway involvement or an arginine-specific protective interaction, is unsupported by the very data used to promote it. The most parsimonious reading is that moving away from the acetate salt is what mattered.
8. An unresolved contradiction in the literature
Sikirić and colleagues, who produced the large majority of the primary BPC-157 literature, state repeatedly that plain BPC-157 is stable in human gastric juice for more than 24 hours (PMID 38980576, also PMID 35125818).
The Diagen patent reports that the acetate salt is 99.92% destroyed within 5 hours in gastric juice at pH 3.0.
Both statements cannot be true. We present this as an unresolved conflict rather than adjudicating it. The two sources used different conditions, different assays and different material, and neither has been independently replicated against the other. Anyone quoting either figure should quote the conflict alongside it.
9. Evidence grading
Established
- Peptide identity, sequence GEPPPGKPADDAGLV, and free peptide molecular weight 1419.53 g/mol.
- Intramuscular pharmacokinetics in rats and in dogs, He et al., 2022.
- That per-oral administration of plain BPC-157 produces measurable effects in rat models.
Claimed but unreplicated
- Superior gastric stability of the arginate salt, single patent source.
- Superior thermal stability of the arginate salt, same source.
Unsupported
- Oral bioavailability of approximately 90%, in any species.
- 1,000 times greater stability as a general property of the molecule.
- Any efficacy in humans, in any salt form, by any route.
There is no published pharmacokinetic study of BPC-157 arginate in any species by any route. The 90% figure has no traceable primary source.
Frequently asked questions
Is BPC-157 arginate a different peptide from BPC-157?+
No. The peptide is identical: GEPPPGKPADDAGLV, free peptide molecular weight 1419.53 g/mol. Arginate and acetate describe only the counter-ion paired with the peptide. Acetate is an anion pairing with the basic sites, the lysine side chain and the N-terminus. Arginine is a cation pairing with the acidic sites, the two aspartate residues and the C-terminal carboxyl. The relevant patent specifies a di-L-arginine salt.
What is pentadeca arginate, and is PDA the same thing?+
Pentadeca arginate, abbreviated PDA, is a marketing name for the arginine salt of the pentadecapeptide BPC-157. It is not a distinct molecule, a distinct sequence, or a separately characterised compound in the scientific literature. Searching the peer-reviewed record for pentadeca arginate returns no pharmacokinetic or efficacy studies under that name.
Does an arginate presentation contain less peptide than an acetate one?+
Yes, per unit mass. Because arginine counter-ions are heavier than acetate, a di-arginate salt is roughly 80.3% peptide by mass against roughly 92.2% for a di-acetate. On that arithmetic a 5 mg di-arginate presentation contains about 4.0 mg of actual BPC-157, against about 4.6 to 4.8 mg for acetate forms, a shortfall of roughly 15 to 19% per milligram. Real salt stoichiometry and residual water vary batch to batch, so net peptide content should be read from the certificate of analysis rather than calculated.
Where does the 1,000x more stable claim come from?+
From a single table in US Patent 9,850,282 B2. In simulated gastric juice at pH 3.0 and 37 °C, the patent reports 84.9% of the arginate salt intact at 5 hours against 0.08% of the acetate. Dividing 84.9 by 0.08 gives approximately 1,061. The figure is arithmetically traceable to that table and to nothing else. It is patent data from a commercial source, it is not peer-reviewed, and it has not been independently replicated.
Where does the 90% oral bioavailability claim come from?+
It has no traceable primary source. The patent contains no bioavailability figure of any kind and the number 90% does not appear in it. The most probable reconstruction, offered as inference rather than fact, is that the gastric-survival percentages of 96.5% at 1 hour and 84.9% at 5 hours were restated as oral bioavailability above 90%, then contrasted against under 3%, the generic textbook figure for unmodified oral peptides. Surviving the stomach is not the same as being absorbed.
Is there any pharmacokinetic study of BPC-157 arginate?+
There is no published pharmacokinetic study of BPC-157 arginate in any species by any route. The only absolute bioavailability measurement for BPC-157 in the literature is He et al., 2022, Front Pharmacol, PMID 36588717, which measured the intramuscular route: 14 to 19% in rats and 45 to 51% in dogs, with an elimination half-life under 30 minutes.
Primary sources
- US Patent 9,850,282 B2, Diagen d.o.o., Rucman, granted 26 December 2017
- He et al., 2022, Front Pharmacol, PMID 36588717
- DOI 10.3389/fphar.2022.1026182
- Sikirić group, gastric juice stability statement, PMID 38980576
- Sikirić group, gastric juice stability statement, PMID 35125818
- Vasireddi et al., 2025, systematic review, PMID 40756949
Related pages
Strictly for laboratory research. Not for human consumption. No therapeutic or medical claims are made, and nothing on this page is guidance for use.