Peptides explained: BPC-157, GLP-1 and the science

Peptides have become one of the most debated topics in health and physical performance. But before discussing whether or not to use them, Dr. Abu Bakri, a board-certified internal medicine physician with clinical hospital experience, proposes understanding what they are, how they work, and what we actually know about their safety and efficacy.

What a peptide is and why the distinction matters

Biologically, peptides are one of the "languages" cells use to communicate, alongside steroid hormones. The most clinically important distinction is whether a peptide has a known receptor or not. GLP-1 agonists (such as semaglutide or tirzepatide) have well-identified receptors, which allows their effects to be predicted with precision. BPC-157 and TB500, by contrast, have no identified receptors, meaning they act in ways we do not fully understand yet.

BPC-157: origins, effects, and legal status

BPC-157 is a 15-amino-acid peptide derived from a larger compound (BPC) found in gastric juice. Croatian researchers in the 1990s identified its potential for tissue repair: in animal models it accelerated healing of tendons, ligaments, peripheral nerves, and gastric ulcers. The original BPC was discovered because animal gastric juice showed wound-healing properties — something physicians in Pavlov's era were already exploiting empirically.

Its proposed mechanisms include activation of VEGF signaling (formation of new blood vessels), modulation of nitric oxide synthesis, and effects on the gut-brain axis that are still under investigation. However, almost all data comes from a single research group, which limits its methodological robustness.

Regarding its legal status in the US, BPC-157 was moved to the FDA's "category 2" list in 2024 (prohibited for compounding). In April 2025 it was removed from that list but has not yet been placed on the category 1 list, which would allow physicians to prescribe it. Compounding pharmacies offer it under other names (pentadecapeptide arginate, PDA), which is essentially the same molecule.

The three risk tiers of the current market

The peptide market presents three tiers with very different quality levels:

• Approved pharmaceuticals (Ozempic, Zepbound): maximum purity, strict quality control, verified dosing.
• Compounding pharmacies: variable quality. The best perform sterility testing and quality control; the worst do not.
• Gray market ("for research purposes only"): composition and purity entirely uncertain, no dose regulation.

About 80% of GLP-1 complications seen in emergency rooms come from compounded versions, not FDA-approved drugs. With unapproved peptides like BPC-157, the risk of contamination or incorrect dosing is even greater.

GLP-1: the context behind the peptide boom

The rise of GLP-1 agonists (semaglutide, tirzepatide, retatrutide) triggered mass interest in other peptides. These are the ones with the strongest evidence base: phase 3 clinical trials with thousands of patients and documented effects on weight, cardiovascular risk, dementia, and sleep apnea. Their expansion also created a parallel market of cheaper compounded versions, with the risks already described.

Other peptides of interest

GHK-Cu (copper-GHK) is widely used to promote collagen synthesis and aesthetic improvement of skin and hair. Russian peptides such as epithalon and pinealon have been studied for potential effects on DNA repair, longevity, and REM sleep, though the quality of that evidence is heterogeneous. Growth hormone secretagogues like tesamorelin or MK-677 act on specific receptors and have a more studied profile.

What is needed: controlled human data

Priority areas for human research include: the effect of BPC-157 on ulcerative colitis (a phase 2 trial with promising but incomplete results already exists), its role in post-surgical musculoskeletal recovery, and its possible modulation of addiction through the gut-brain axis. Without controlled trials, anecdote — even from physicians — is not sufficient evidence to draw conclusions.

Conclusion

Peptides are a field with real potential, but that potential cannot be evaluated without rigorous human data. Until those studies exist, the most responsible position is to stay informed, obtain any approved peptide through proper regulatory channels, and avoid the gray market, where purity and content are inherently uncertain.