Pentadeca Arginate (PDA)

The di-arginine salt form of the 15-amino-acid BPC-157 sequence, marketed as a more stable presentation of the same peptide; no peer-reviewed study or clinical trial exists under the pentadeca arginate name.

Also referenced as: PDA, BPC-157 arginate, BPC-157 arginine salt, Arg-BPC, bepecin di-L-arginine salt

Also appears in: Other

What is Pentadeca Arginate (PDA)?

Pentadeca arginate (PDA) is a salt form of BPC-157, not a different peptide: the same 15-amino-acid sequence (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val, about 1,420 Da) paired with L-arginine as the counterion instead of the acetate or free base in which BPC-157 is usually supplied. The form traces to a 2013 Slovenian priority filing from the company Diagen d.o.o. (inventor Rudolf Ručman, a long-standing coauthor of the Zagreb group that originated BPC-157), published as WO 2014/142764 on September 18, 2014 and granted in the United States as US 9,850,282 on December 26, 2017. The granted claims cover salts of the pentadecapeptide with two molecules of a basic amino acid (arginine, lysine, or ornithine), and the specification names the di-L-arginine salt, abbreviated Arg-BPC, as the form with the most favorable properties. One reason PDA appears in compounding and research catalogs is that it carries a name that is not “BPC-157” while delivering the same molecule; another is that the arginate is promoted as more heat- and acid-stable. The pharmacology, evidence base, and most of the regulatory history are those of BPC-157.

How it works

Everything known about how PDA acts in tissue comes from studies of BPC-157 preparations (acetate, free base, or an unspecified form); no study has examined the biological activity of the arginate salt separately. Once the salt dissolves, the arginine and the peptide separate into ions, and what reaches a receptor is the same pentadecapeptide. The mechanisms below are therefore BPC-157 mechanisms.

• Pro-angiogenic signaling through VEGFR2 — BPC-157 increased vessel density in the chick chorioallantoic membrane, promoted endothelial tube formation, accelerated blood-flow recovery in rat hind-limb ischemia, and increased VEGFR2 expression and internalization with activation of the VEGFR2–Akt–eNOS pathway in human endothelial cells (Hsieh et al., Journal of Molecular Medicine, 2017; 95(3):323–333).
• Tendon fibroblast outgrowth, survival, and migration — in rat Achilles tendon explants and cultured tendon fibroblasts, BPC-157 accelerated outgrowth, improved survival under hydrogen-peroxide stress, and increased migration and spreading through phosphorylation of FAK and paxillin, without changing proliferation (Chang et al., Journal of Applied Physiology, 2011; 110(3):774–780); it also increased growth hormone receptor expression in tendon fibroblasts, amplifying the proliferative response to growth hormone (Chang et al., Molecules, 2014; 19(11):19066–19077).
• Gastric cytoprotection and the nitric oxide system — the Zagreb group describes BPC-157 as a cytoprotective agent that interacts with the nitric oxide system and counteracts mucosal and vascular injury in rodent gastrointestinal models, with cross-talk to angiogenic growth factors in gut, tendon, ligament, muscle, and bone healing (Sikiric et al., Inflammopharmacology, 2006; 14(5–6):214–221; Seiwerth et al., Current Pharmaceutical Design, 2018; 24(18):1972–1989).
• What the counterion does and does not change — pharmaceutical salt selection alters solid-state and formulation properties: hygroscopicity, melting behavior, solubility and dissolution rate, and the shelf stability of the dry powder and of solutions (Berge et al., Journal of Pharmaceutical Sciences, 1977; 66(1):1–19). It does not change the active moiety, its receptor interactions, or its metabolic fate after absorption. A more stable salt can matter for storage, for oral formulations exposed to stomach acid, and for how much intact peptide survives to the site of absorption; it cannot, on its own, create pharmacological effects the parent peptide lacks. The two arginine molecules per peptide amount to roughly 1–2 mg of arginine in a 5–10 mg vial, a small fraction of the grams of arginine in an ordinary daily diet, and contribute no meaningful pharmacology of their own.

Research status

There is no peer-reviewed literature on pentadeca arginate. A PubMed search for “pentadeca arginate,” “BPC-157 arginate,” or an arginine salt of BPC 157 returns no records as of November 2026, and ClinicalTrials.gov lists no study of the arginate form. The only data specific to the salt are the applicant’s tables in the Diagen patent (US 9,850,282; WO 2014/142764): in the solid state at 50 °C and 65% relative humidity the di-arginine salt retained about 99% purity at 90 days versus about 86% for BPC-157 acetate; in aqueous solution at 50 °C it retained about 99% at 388 hours versus about 21% for the acetate; and in simulated gastric juice at pH 3 it retained far more intact peptide over five hours than the acetate. These are stability measurements made by the patent holder, never replicated in a journal, and the patent reports no pharmacokinetic, bioavailability, or comparative efficacy data for the salt in any species. Whether the arginate changes blood levels of the peptide after oral or subcutaneous administration has not been measured.

The stability claim also has to be read against the parent peptide. BPC-157 was named “stable gastric pentadecapeptide” because its originators report no degradation in human gastric juice for more than 24 hours (Sikiric et al., World Journal of Gastroenterology, 2022; 28(1):23–46, an editorial by the originating group). The arginate is therefore a more stable form of a peptide already described as unusually stable, and the practical difference for a lyophilized vial kept cold is undemonstrated.

The human evidence for the active moiety is thin and belongs to BPC-157 preparations:

• Ulcerative colitis (Pliva, Croatia, PL 14736) — the only controlled human efficacy data FDA identified in its May 11, 2026 evaluation is a 2005 meeting abstract (Ruenzi et al., Gastroenterology 2005; 128:A584) of a multicenter, randomized, double-blind trial in which 53 subjects with mild-to-moderate ulcerative colitis received an 80 mg BPC-157 enema or placebo daily for two weeks; 46 completed, the estimated between-group difference in disease activity index was 1.6 points with a confidence interval spanning zero, and FDA judged the data inadequate to support efficacy or safety. The program did not advance to a full publication or an approval.
• Oral pharmacokinetics — NCT02637284 (PharmaCotherapia d.o.o., Phase 1, Hospital Ángeles Tijuana, started October 2015) planned 42 healthy volunteers receiving 1 mg oral tablets of bepecin (PCO-02, BPC-157); the record was posted December 22, 2015, has not been updated since, carries a status of unknown, and has no posted results. FDA’s 2026 evaluation states there is no information with which to assess the pharmacokinetics of BPC-157 in humans.
• Active trials — NCT07437547 (Hudson Biotech, Phase 2, Peking University Shenzhen Hospital) began recruiting February 2, 2026 for a 120-patient, randomized, double-blind, placebo-controlled trial of subcutaneous BPC-157 for MRI-confirmed grade II hamstring strain, with return to sport and MRI injury volume as co-primary endpoints and primary completion estimated for February 14, 2027; NCT07803250 (University of Arkansas, Phase 1 pilot, 30 planned, sham no-treatment control) of BPC-157 after arthroscopic rotator cuff repair is listed as not yet recruiting with a January 2027 start. Neither specifies a salt form, and neither is a PDA study.
• No PDA-specific safety data — FDA’s adverse-event database entries for BPC-157 (injection-site reaction, shortness of breath, diffuse hyperpigmentation and gingival darkening, causality unclear) and FDA’s stated concern about immunogenicity from peptide-related impurities and aggregates in injected products apply to any salt of the peptide; nothing has been published on the arginate separately.

Common dosage forms

PDA is supplied by research vendors as lyophilized powder in single vials, most often labeled 5 mg or 10 mg, and increasingly as oral capsules, the format the patent’s acid-stability data were meant to enable. Compounding pharmacies that adopted the PDA name dispense it as prescriber-compounded subcutaneous injection solutions and oral capsules. Labels do not consistently state whether the milligram figure refers to the peptide or to the salt; two arginine molecules add roughly 350 Da to a 1,420 Da peptide, so a salt-weight label contains about 80% peptide by mass. No approved product of any salt of BPC-157 exists in any country.

Key considerations

• Same molecule, different name — PDA, pentadeca arginate, BPC-157 arginate, and Arg-BPC all describe the arginine salt of BPC-157; the active moiety, mechanism, and evidence base are those of BPC-157. Claims that PDA is a “next-generation” or “upgraded” peptide rest on applicant-generated stability tables in a patent, not on any published comparative study.
• Regulatory status. The Research Market status reflects that no clinical trial, investigational application, or regulatory submission exists for the arginate salt itself. The BPC-157 trials now recruiting concern unspecified or acetate preparations.
• Regulatory position is BPC-157’s, and the salt is not grandfathered — FDA placed BPC-157 in Category 2 of its 503A bulk-substance list (significant safety risk) on September 29, 2023, removed it on April 22, 2026 after the nominators withdrew, and on July 23, 2026 its Pharmacy Compounding Advisory Committee voted 8–6 with one abstention to recommend adding BPC-157 (free base) and BPC-157 acetate to the 503A bulks list, against the recommendation of FDA staff; the vote is non-binding and rulemaking has not concluded. On October 28, 2026 HHS filed a draft enforcement-discretion policy (91 FR 68526, published October 30, 2026, comments through November 13, 2026) under which it does not intend to act against state-licensed pharmacies, federal facilities, or physicians compounding six peptides under section 503A, BPC-157 acetate among them, while rulemaking proceeds; the discretion is conditioned on the substance matching the identity in the policy’s appendix, it is not an approval, and it does not name the arginate. FDA treats each salt of an active moiety as a distinct bulk drug substance, so neither the policy nor an eventual listing of the free base or acetate would by itself cover the arginate, which was neither nominated nor evaluated, and FDA’s evaluation flagged the sale of multiple salts and derivatives under the BPC-157 name as a patient-safety risk in its own right.
• Anti-doping — BPC-157 has been named as an example under section S0 (non-approved substances) of the WADA Prohibited List since January 1, 2022; a salt form delivers the same prohibited moiety.
• Evidence gaps specific to the salt — no pharmacokinetic comparison with BPC-157 acetate, no in vivo efficacy comparison, no independent replication of the patent’s stability data, no human study of any kind, and no immunogenicity or impurity characterization of commercially sold arginate material.