BPC-157 Side Effects

What side effects have been reported in humans?

The published studies using BPC-157 in humans consist of three small, uncontrolled studies on knee pain, interstitial cystitis, and the safety of intravenous administration (30 people in total). According to the 2026 systematic review, no treatment-related side effects were reported in any of these studies; however, the review found the methodological quality of all three studies low and the certainty of the evidence very low. ^[3]

In evaluating the same data, the FDA emphasizes these points: the studies are short-term and small, the doses used are exploratory, the authors gave limited information on safety data, and how safety monitoring was done is unclear in most. In the studies in healthy volunteers conducted by enema and presented only as conference abstracts, the most commonly reported side effects are headache and gas. ^[1]

What is in the FDA’s adverse event records?

Through 4 December 2025, the FDA found three reports for BPC-157 in the adverse event reporting system FAERS; all three concerned injectable products: ^[1]

• In one woman, redness and swelling at the injection site lasting 9 days; the person was using another injectable peptide (thymosin) during the same period.
• In one man, shortness of breath and an emergency department visit; there was no information on duration of use, concomitant medicines, and timing.
• In one woman using a mixture containing BPC-157 and TB-500 labeled “for research purposes only,” widespread skin darkening and darkening of the gums; when the product was stopped and restarted, the same picture recurred. Because of this recurrence, the FDA finds it likely that the event was related to the product, but because the product contained two peptides, the share of BPC-157 cannot be distinguished.

Three cases were also found in the FDA’s food and supplement complaint system; in all of them the product was a multi-ingredient supplement and details were missing. The FDA found no case report associated with BPC-157 in the published literature. ^[1]

Why is the frequency of side effects unknown?

The frequency of a drug’s side effects emerges from large controlled studies and regular post-licensing reporting. For BPC-157, neither exists. The FDA states that side effects of drugs compounded in pharmacies in the US are generally not reported to the FDA and that, unless a report is made, the agency may not be aware of these events. FAERS data themselves are also limited: it is not certain that a reported event is due to the product, and not all events are reported. ^[1]

As with a licensed drug, there is also no license holder doing regular safety reporting. As a result, a small number of reports does not mean a small number of side effects; it may only show that the monitoring system does not see these products.

What do animal toxicity studies show?

In an article reported by the FDA, toxicity tests were done with intramuscularly administered BPC-157 in rats and dogs. The findings are summarized below; doses are deliberately not given, because animal doses cannot be carried over to humans. ^[1]

Of these findings, the FDA describes the changes in clotting properties and the liver-related markers as “safety signals that may be clinically meaningful,” and concludes that the existing toxicity studies are insufficient in scope and duration for a safety assessment aimed at possible clinical uses. ^[1]

Can BPC-157 cause cancer?

This question has not been answered in humans, and there is no carcinogenicity study for BPC-157. ^[1] The source of the debate is that BPC-157 increases blood vessel formation (angiogenesis): in one study it was shown to increase vessel density in the chick embryo membrane and in cell culture, and to raise the number of vessels and VEGFR2 receptor expression in ischemic leg muscle in rats. ^[6]

There are two interpretations in the literature:

• Theoretical risk: A 2025 review, based on cell studies, lists pathological blood vessel formation and excess nitric oxide production among possible undesirable effects; it recalls that pathological blood vessel formation plays a role in the proliferation of tumor cells. ^[4] Polish researchers also write that the signal that increases blood vessel formation remains a plausible tumor-supporting hazard and that there is no published study showing that BPC-157 inhibits tumor growth or spread in vivo. ^[5]
• Opposing view: The same 2025 review also reports that BPC-157 has been reported in some studies to suppress uncontrolled cell proliferation and to be able to affect blood vessel formation in different directions depending on the tissue. ^[4] Józwiak and colleagues, however, state that the evidence this opposing view rests on consists of a single 2004 melanoma cell line experiment and has not been replicated. ^[5]

For people with a history of cancer or who may have an undiagnosed tumor, the risk of BPC-157 is therefore unknown; this uncertainty is not a reassurance but an unmeasured risk.

What is the risk of immune response (immunogenicity)?

The FDA states that peptides, like proteins, can produce an immune response and that this response can increase when given subcutaneously or intranasally. Outcomes can range from antibody formation without symptoms to life-threatening reactions and cannot be predicted in advance. Peptides are prone to aggregation; aggregation and peptide impurities left over from synthesis can increase this risk. The FDA could not find a study examining whether BPC-157 products produce an immune response. ^[1] The BPC-157 row on the FDA’s category page also writes about this risk and that the agency does not have enough information to know whether BPC-157 would harm humans. ^[2]

Injection and product purity risks

In peptide products of unclear source, risk comes from the quality of the product as much as from the substance itself:

• Lack of analysis: Most of the BPC-157 certificates of analysis the FDA reviewed gave only a purity percentage; there were no tests for defined impurities, aggregation, microbial load, and bacterial endotoxin. Endotoxin testing is a critical quality attribute for an injectable product. ^[1]
• Purity claim: A team doing peptide synthesis states that reaching 99% purity is extremely difficult and that basic analytical data such as HPLC are not accessible for BPC-157 on the market. ^[5]
• The picture measured in similar products: There is no comparable test-purchase study for BPC-157. In a study examining only three semaglutide vials obtained from illegal online pharmacies selling without a prescription, the measured purity was in the range of 7.7–14.37% (99% on the label), the peptide amount was 28.56–38.69% more than stated on the label, and endotoxin was detected in all three samples; no viable microorganisms were found at the time of testing. ^[7] This result belongs to another peptide and a very small sample; it is not a measurement of BPC-157 products. Even so, it shows that purity, content amount, and endotoxin level in the unregulated peptide channel cannot be assumed from the label.

Additional risk for athletes

WADA’s 2026 list names BPC-157 in class S0; the substance is prohibited at all times, in and out of competition. ^[8] The presence of BPC-157 in mixture products or in products with an incomplete label creates a risk that the athlete commits an anti-doping rule violation unknowingly.

For whom is uncertainty especially high?

For the following groups, data are absent or theoretical concerns are more pronounced:

• Pregnancy and breastfeeding: Apart from the single study in pregnant rats, the full reproductive cycle and postnatal development have not been examined; there are no human data. ^[1]
• History of cancer: The risk is unknown because of the theoretical concern based on the effect of increasing blood vessel formation. ^[4]
• People with clotting disorders and those using blood thinners: The meaning in humans of the clotting test changes seen in animal studies is unknown. ^[1]
• Licensed athletes: WADA prohibition. ^[8]

Limits of this page

This page summarizes what is known and not known about the safety of BPC-157 in light of published data and official assessments. It contains no dose, administration, or “safer use” advice; no safe form of use has been defined in humans. A symptom that develops after using BPC-157 is evaluated by a physician, and side effects can be reported to the national pharmacovigilance system.