Peptide Library

Human study PLS-00034

Intra-Articular Injection of BPC 157 for Multiple Types of Knee Pain.

Case series · 17 participants enrolled

Version 1 · published November 7, 2026 · evidence through November 7, 2026 · research snapshot 2026.1.1 · methodology ev-1 · Automated assessment by AI (claude-opus-5-5 and claude-sonnet-5-5), not reviewed by a person.

Only the abstract was available. Essential methods may be missing, which limits what can be judged.

Reports of this study

Every publication, registration and abstract describing this one study. Participants are counted once.

  • Intra-Articular Injection of BPC 157 for Multiple Types of Knee Pain.primary · Alternative therapies in health and medicine · 2021-07-01 · PMID 34324435

Design and participants

Design
Case series
Population
Primary care patients with knee pain of multiple causes who received intra-articular peptide injections, identified by a 1-year chart review (2019-2020).
Conditions
Knee pain (multiple causes), Knee osteoarthritis
Setting
Institute for Hormonal Balance, Orlando, Florida (primary care setting); retrospective chart review with telephone follow-up survey. (United States)
Planned enrollment (registry)
Not reported
Enrolled
17
Randomized
Not reported
Completed follow-up
16
Funding
Not reported.
Authors’ conflicts
Not reported.

Intervention and comparator

What each group received. Related peptides, analogs and combinations are never treated as the compound itself.

  • BPC-157 alone (intervention) · bpc-157 · BPC-157 given alone as an intra-articular knee injection. · intra-articular · Follow-up varied; most patients had been injected 6 months to 1 year before the survey. · 12 assigned
  • BPC-157 + TB4 (intervention) · bpc-157 (combination) · Two peptide injections of BPC-157 combined with thymosin beta-4 (TB4), given intra-articularly. · intra-articular · Follow-up varied; most patients had been injected 6 months to 1 year before the survey. · 4 assigned

What the authors reported

As stated in the sources. This is the authors’ account, not Peptide Library’s assessment.

Improvement in knee pain (patient-reported)

primary outcome · patient-important · Variable; mostly 6 months to 1 year after injection · Telephone survey asking patients to rate pain before injection and the degree to which the injection helped; no validated tools used.

  • BPC-157 alone: proportion 91.6 — 11 of 12 patients (91.6%) had significant improvement in knee pain; 1 had no improvement.
  • BPC-157 + TB4: proportion 75 — 75% showed significant improvement; 25% had no relief.
  • —: proportion 87.5 — Overall, 14 of 16 patients (87.5%) had relief of knee pain.

Duration of pain relief

secondary outcome · patient-important · Variable · Patients were asked how long the peptides helped ease the pain (telephone survey).

  • No results reported.

Adverse events

None reported. That is not evidence of safety.

Monitoring: Not reported in the abstract.

The authors concluded (paraphrased): The authors concluded that this small study suggests intra-articular BPC-157 helps relieve multiple types of knee pain. They called for future studies with follow-up MRI.

Peptide Library’s assessment

An automated assessment, made by AI separately from the authors’ conclusions and not reviewed by a person. How risk of bias is assessed.

Limitations

  • no control group: All patients received peptide injections; there was no placebo, usual care or untreated comparison group.
  • small or imprecise: Only 16 patients were surveyed, with 4 in the combination group; no confidence intervals were reported.
  • inappropriate endpoint: Pain improvement was recalled by phone using no specific or validated tools; 'significant improvement' was not defined.
  • selection bias: Retrospective chart review from a single clinic; how patients were selected for injection and inclusion is not described.
  • confounding: Knee pain had multiple causes, and co-treatments and the natural course were not accounted for. Four patients also received TB4.
  • short follow up: Follow-up timing varied across patients, mostly 6 months to 1 year, and was not standardized.
  • other: Recall bias is likely because patients rated pre-injection pain retrospectively during the phone survey.
  • abstract only: Only the abstract is available; methods, adverse events, funding and conflicts are not reported.

Improvement in knee pain (patient-reported): Serious concern (Structured limitations appraisal)

For uncontrolled studies, case series and case reports, where no validated comparative tool applies. It lists limitations; it is not a risk-of-bias rating.

Domain judgments
Control groupSerious concernNo comparison group; all 16 surveyed patients received BPC-157 alone or with TB4.
Selection of participantsSerious concernRetrospective 1-year chart review at a single hormone clinic; selection criteria for treatment are not described.
ConfoundingSerious concernHeterogeneous causes of knee pain, a TB4 co-intervention in 4 patients, and no adjustment for natural history or other treatments.
Follow-up and attritionSome concern16 of 17 patients were reached, but follow-up duration varied widely, mostly 6 months to 1 year.
Outcome measurementSerious concernUnblinded retrospective phone recall of pain and benefit; no specific measurement tools were used, per the abstract.
Completeness of reportingSerious concernOnly dichotomized 'significant improvement' proportions are given; pain scores and relief duration results are not reported.
PrecisionSerious concernVery small sample (12 and 4 patients) with no confidence intervals or statistical testing reported.
Funding and conflicts of interestNot reportedThe abstract does not report funding sources or author conflicts of interest.

An uncontrolled retrospective series with recall-based, unvalidated pain outcomes and a very small sample carries serious concern across several domains.

Version 1 · published November 7, 2026 · evidence through November 7, 2026 · research snapshot 2026.1.1 · methodology ev-1 · Peptide Library structured appraisal pl-1 · Automated assessment by AI (claude-opus-5-5 and claude-sonnet-5-5), not reviewed by a person.

Claims this study informs

  • Very low certainty Knee pain intensity

Where each value comes from

  • arms: PMID 34324435, abstract (Results, sentences 1 and 3) · extracted by AI (automated, not verified by a person) · abstract only
  • author_conclusion: PMID 34324435, abstract (Conclusion, sentence 1) · extracted by AI (automated, not verified by a person) · abstract only
  • design: PMID 34324435, abstract (Methods, sentences 1-3) · extracted by AI (automated, not verified by a person) · abstract only
  • limitations: PMID 34324435, abstract (Methods, sentences 3 and 7) · extracted by AI (automated, not verified by a person) · abstract only
  • outcomes: PMID 34324435, abstract (Methods, sentences 6-7) · extracted by AI (automated, not verified by a person) · abstract only
  • participants: PMID 34324435, abstract (Methods, sentences 4-5) · extracted by AI (automated, not verified by a person) · abstract only
  • population: PMID 34324435, abstract (Methods, sentences 1-2) · extracted by AI (automated, not verified by a person) · abstract only
  • results: PMID 34324435, abstract (Results, sentences 2-5) · extracted by AI (automated, not verified by a person) · abstract only

  • Version 1 · published November 7, 2026 · evidence through November 7, 2026 · research snapshot 2026.1.1 · methodology ev-1 · Automated assessment by AI (claude-opus-5-5 and claude-sonnet-5-5), not reviewed by a person.

These assessments describe published research. Records marked automated were produced by AI under the published methodology and have not been reviewed by a person; they can contain errors. None of this is medical advice, not a statement about any product’s safety for human use, and not a regulatory approval. Peptide Library’s vendor and partner relationships play no part in them (editorial independence).