PDA vs. BPC-157: The Same Peptide in a Different Wrapper
Pentadeca Arginate is marketed as a breakthrough oral peptide. The chemistry says otherwise.
The Marketing Pitch
If you’ve searched for oral BPC-157 recently, you’ve likely encountered Pentadeca Arginate (PDA) — positioned as a legal, bioavailable alternative to BPC-157 that sidesteps the FDA’s September 2023 Category 2 prohibition. Some vendors claim PDA offers “99.9% oral bioavailability,” a figure that would represent one of the most remarkable pharmaceutical achievements in history.
We spent weeks investigating PDA — the patent, the chemistry, the published research, and the regulatory positioning. Here’s what we found.
PDA contains the exact same 15-amino-acid peptide sequence as BPC-157 (GEPPPGKPADDAGLV). The only difference is the counter-ion: arginine instead of acetate. Zero peer-reviewed studies have been published on PDA specifically, and the “99.9% bioavailability” claim has no published scientific basis.
Following the Chemistry
The PDA story starts with a single patent: WO2014142764A1 (granted as US9850282B2 in 2017). The inventor is Rudolf Ručman, a longtime collaborator of Predrag Sikirić — the Zagreb researcher behind virtually all BPC-157 research. The assignee is Diagen d.o.o., a Croatian company.
The patent describes the di-L-arginine salt of BPC-157. That’s it. Same peptide sequence. Same 15 amino acids. Same molecular mechanism. The arginine is a counter-ion — a companion molecule that balances the charge of the peptide in its solid form. When dissolved, the peptide and arginine separate.
To understand why this matters: imagine you have table salt (sodium chloride) and potassium chloride. The chloride is the same in both. Changing the counter-ion changes some physical properties — solubility, crystal structure, taste — but the active chloride ion is identical. The same principle applies here. The active peptide in PDA is BPC-157.
The “99.9% Bioavailability” Claim
This number appears across multiple vendor sites. We traced it through every citation chain we could find. The result: no published, peer-reviewed study supports this figure.
For context on why 99.9% oral bioavailability for a peptide is biologically implausible:
Novo Nordisk spent over a decade and invested billions developing Rybelsus (oral semaglutide). Using their proprietary SNAC absorption enhancer — arguably the most advanced oral peptide delivery technology ever commercialized — they achieved 0.4% to 1% oral bioavailability. This was celebrated as a pharmaceutical breakthrough.
The claim that simply swapping acetate for arginine as a counter-ion achieves 99.9% oral bioavailability — surpassing what the world’s largest peptide pharmaceutical company achieved with a decade of R&D — is extraordinary. Extraordinary claims require extraordinary evidence. In this case, there is no evidence at all.
The only source for PDA-specific data is the patent itself, which is not peer-reviewed research. Patents are legal documents designed to establish intellectual property claims. They are not subject to peer review, statistical scrutiny, or reproducibility requirements.
The Published Research Situation
After exhaustive searching of PubMed, Google Scholar, ClinicalTrials.gov, and all major scientific databases:
Zero peer-reviewed journal articles have been published comparing BPC-157 arginate to BPC-157 acetate in any model — animal or human. Zero pharmacokinetic studies of PDA exist. Zero stability comparison studies exist. Zero human trials of PDA exist.
All 100+ published BPC-157 studies used the standard acetate or free form, not the arginate salt. When vendors cite “BPC-157 research” to support PDA efficacy, they’re referencing studies of a different formulation — while simultaneously arguing PDA is a distinct compound for regulatory purposes.
This creates a logical contradiction: either PDA is meaningfully different from BPC-157 (in which case BPC-157 research doesn’t apply), or it’s essentially the same compound (in which case the regulatory distinction doesn’t hold).
The Regulatory Shell Game
The business logic behind PDA is straightforward. In September 2023, the FDA moved BPC-157 to Category 2, prohibiting its use in compounding. Vendors selling injectable BPC-157 faced a compliance problem. But oral supplements occupy a different regulatory space — if a substance qualifies as a dietary supplement under DSHEA, FDA enforcement is different.
PDA’s positioning as “not BPC-157” serves this purpose. By calling it a different compound, vendors argue it falls outside the Category 2 prohibition.
The problem: legal experts including attorneys at Holt Law and Frier Levitt have noted that oral BPC-157 supplements are “just as illegal as the injectable version.” BPC-157 is a synthetic peptide, not a recognized dietary ingredient under DSHEA. No New Dietary Ingredient Notification (NDIN) has been filed and accepted for PDA or BPC-157. The FDA simply hasn’t prioritized enforcement against oral peptide supplement sellers yet — a fact that could change.
What You’re Actually Paying For
PDA products typically command a premium over standard BPC-157 capsules, with prices ranging from $130–$160 for 60 capsules. The premium is justified by the bioavailability and regulatory claims examined above.
Raw peptide costs for BPC-157 (in either salt form) are estimated at $10–25 per bottle quantity. The markup structure is standard for supplements, but the value proposition depends on claims that currently lack published scientific support.
The Bottom Line
PDA is not a new peptide. It’s not a breakthrough formulation. It’s BPC-157 with a different counter-ion and a marketing strategy designed to navigate a regulatory landscape that increasingly restricts peptide sales.
None of this means oral BPC-157 (in any salt form) doesn’t work — it means nobody has proven that it does at a systemic level, and the bioavailability figures used to sell premium products have no published scientific basis.
If you’re considering PDA:
What you’re getting: BPC-157 in arginine salt form.
What you’re not getting: A meaningfully different compound, proven superior bioavailability, or a clear regulatory shield.
What the honest answer is: We don’t know if oral BPC-157 achieves meaningful systemic absorption in humans, regardless of the salt form. The strongest rationale for any oral BPC-157 product remains gut-specific applications where the peptide contacts GI tissue directly.
We searched PubMed, Google Scholar, ClinicalTrials.gov, and patent databases for all published research on Pentadeca Arginate and BPC-157 arginine salt through February 2026. We reviewed patent WO2014142764A1 / US9850282B2 in full. We contacted multiple vendors selling PDA products requesting source data for bioavailability claims. Full methodology available on our methodology page.
This article will be updated as new research becomes available. Last reviewed: February 20, 2026.