Peptides: The Science, Uses & Safety | Dr. Abud Bakri

The episode opens by separating peptide discussion into more useful biological categories. Bakri describes peptides as one of the body’s signaling languages and distinguishes compounds with identified receptors, such as GLP-1 agonists, from peptides such as BPC-157 and TB-4 for which no receptor has been identified. Huberman emphasizes that an unknown receptor is not the same as proof that no receptor exists; the target may simply remain elusive.

That distinction also changes the proposed mechanism. Bakri says some peptides might modify existing proteins or help proteins interact in ways that affect gene transcription. He describes Russian peptides as epigenetic modifiers that may bind DNA and influence chromatin accessibility. The conversation compares this with steroid hormones acting through receptors in the nucleus, while leaving the precise mechanisms of the less-characterized peptides unresolved.

The discussion then turns to BPC-157 and the history of searching animal tissues for medicines. Bakri contrasts this with the longer tradition of finding medicines in plants, citing aspirin, metformin, and statins as examples of plant- or fungus-derived discoveries. He says BPC-157 is a 15-amino-acid fragment associated with a much larger, roughly 40,000-dalton protein called BPC; he stresses that people do not naturally produce BPC-157 itself, despite claims he has seen online.

Bakri traces the interest in gastric compounds to Ivan Pavlov’s work with dogs. In his account, Pavlov collected gastric juices and sold them as a remedy; people took the material orally for digestive discomfort and sometimes wound healing, without knowing which ingredients were responsible. Huberman notes that the mixture would have contained many substances, so these historical uses cannot identify BPC-157 as the active ingredient.

A second strand of the story is Hans Selye’s stress-adaptation research. Bakri recounts that stressed animals showed enlarged adrenal glands, damage to the gastric lining, and shrinkage of the thymus and lymphatic tissues. This led researchers to hypothesize that the gut might contain a cytoprotective or organ-protective compound, since the stomach is also an endocrine tissue. The account presents this as the rationale that motivated a search, not as proof of a specific therapeutic effect.

Bakri dates the Croatian group’s work to 1991. He says they first identified the larger BPC protein and then investigated which component might account for biological effects, identifying the 15-amino-acid BPC-157 fragment. He adds that gastric juices may contain other peptides that have or have not yet been identified, and uses carnosine and carnitine found in cattle muscle to illustrate the broader idea that different tissues may contain characteristic peptides.

The opening therefore sets up both the appeal and the evidentiary gap around BPC-157: the proposed history connects animal-tissue research, stress physiology, and a specific peptide fragment, while the episode’s introduction characterizes formal human research as extremely limited and points to animal studies as much of the basis for interest. Historical use of a complex gastric mixture does not by itself establish the safety, mechanism, or efficacy of isolated BPC-157 in people.

Bakri says early BPC research examined a broad range of animal injuries, including severed tendons and ACLs and burn wounds. In one reported model, topical BPC was associated with fewer gastric ulcers in mice with burn injuries. He argues that the compound’s original rationale was gastric protection and an anti-stress effect; its later association with musculoskeletal recovery grew after Achilles-tendon findings attracted bodybuilding interest. These are animal findings, not demonstrations of clinical benefit in people.

The speakers note that nerve and connective-tissue repair pose different biological problems. Huberman describes central nervous system regeneration as particularly difficult and asks how one peptide could affect neurons, fibroblasts, and collagen-containing tissues. Bakri’s proposed account is that BPC modulates several growth and healing pathways: animal tissue-injury models show increased VEGF signaling and angiogenesis, alongside cell migration and greater access for healing factors. He links angiogenesis to the safety debate because new blood-vessel formation could have unwanted consequences. The episode does not establish a single receptor or a settled mechanism.

Bakri also describes an anti-stress effect in animal experiments. Corticosteroids usually slow or halt wound healing in the models he discusses, whereas BPC-treated animals healed at a similar or faster rate. The hosts distinguish this from simply suppressing inflammation: they suggest that healing may require inflammatory signals and ask whether BPC instead helps recruit immune and repair processes. Bakri adds a tendon model in which growth-hormone receptors increased, as well as proposed downstream changes in nitric-oxide synthesis and blood-vessel dilation. He presents these as model-specific observations and theories.

The conversation then turns to neurological and behavioral observations in animals. Bakri recounts mouse experiments in which BPC reduced apparent intoxication and withdrawal behaviors, and says he has heard anecdotal reports that oral BPC blunts the perceived effect of Adderall. He describes BPC as potentially homeostatic and connected to gut–brain signaling, while acknowledging that the mechanism is poorly understood. Reports of low mood, low energy, and anhedonia are raised as possible adverse experiences; the speakers do not treat these anecdotes as proof of a defined neurological action.

On safety, Bakri says animal studies administered doses up to 1,000 times a reference dose without clear adverse effects, but a usable LD50 has not been established. He explains that LD50 is the dose expected to kill half the test animals and that its absence complicates drug development and clinical prescribing. Huberman underscores that toxicology testing is part of drug evaluation. The discussion therefore treats the absence of reported toxicity as an evidence gap rather than evidence that BPC is safe.

Human evidence described in this segment is limited. Bakri points to small Phase 1 and Phase 2 trials of rectal BPC enemas for ulcerative colitis, including doses up to 80 milligrams over several weeks. The underlying data were not available to the speakers beyond abstracts; Bakri says the Phase 1 trial reported no adverse effects. He also says measured BPC-157 was not found in participants’ blood after oral or rectal administration, suggesting either rapid breakdown or local retention near gastric tissue. These observations do not establish the safety of injection or other routes, and the small, incompletely accessible evidence base remains a major limitation.

The hosts return to a basic unknown: whether BPC is naturally present in circulating blood or largely confined to the gut. Bakri says they do not have those data and notes that injected material would be systemic. He cites a 2024 paper that could detect BPC-related fragments in the context of anti-doping testing, but says its overall distribution and dynamics remain unclear. For oral or rectal use, he recounts measurements in which BPC-157 was not detected in blood, leaving rapid breakdown and local retention as possibilities rather than settled explanations.

The limited ulcerative-colitis trials are discussed with explicit caveats. Bakri says the Phase 1 trial primarily assessed safety and reported no adverse effects; a small Phase 2 study, involving about 40 patients, showed at least a positive signal. The studies were conducted in Croatia, and the speakers say the detailed data were unavailable to them beyond abstracts. Huberman asks whether researchers should discount findings because of where a trial was conducted; Bakri argues that study quality, including randomized, double-blind, placebo-controlled design, matters more than national origin, while acknowledging skepticism about some Soviet-era research and the possibility that reported effects may not replicate at the same strength.

That exchange does not remove the evidentiary limitations. The Phase 2 result is described only as a signal, based on a very small sample, and the speakers lack the full report. They also distinguish rectal or oral exposure from injection: findings about one route cannot establish safety or exposure for another. Even the reported absence of detectable blood levels leaves open whether the peptide was quickly degraded or remained near the gut lining.

Huberman and Bakri then describe the U.S. regulatory and prescribing uncertainty as they understood it during the conversation. They say BPC-157 had not received FDA approval and discuss its changing status on compounding categories, including a period when it was placed on a category-two list and later removed without yet being placed on category one. Bakri says some prescribers use the name pentadecapeptide arginate (PDA) for a form they regard as BPC-157, but he also notes that state medical boards may take different positions. The speakers describe telehealth prescribing as subject to the rules where the patient is located and characterize enforcement as uneven and potentially uncertain.