Three physicians at the University of Missouri-Kansas City and Saint Luke’s Mid America Heart Institute have published a review that does something the injectable-peptide market rarely gets: a compound-by-compound account of what is claimed, what mechanism is proposed, and what could go wrong. It covers BPC-157, TB-500, CJC-1295 and ipamorelin, MK-677, melanotan-II, GHK-Cu, retatrutide and the veterinary steroid trenbolone. It is a narrative review. It carries no new patient data and no figure for how often any of the harms it describes actually happens. What it offers is a clear statement, in a clinical journal, of how thin the human evidence is.
What it says about the compounds this site covers
On BPC-157, the authors are blunt: no peer-reviewed randomised controlled trial has shown a clinical benefit in humans, and most of the supporting evidence comes from preclinical animal models produced by what they describe as a highly isolated group of investigators. They then take the proposed mechanism and read it as a risk rather than a selling point. BPC-157 is said to accelerate blood vessel growth by upregulating VEGFR2 and its downstream signalling; in healthy tissue that drives healing, but where an undetected malignancy is present the same signalling supports tumour blood supply. They raise sustained overactivation of the transcription factor Egr-1 on similar grounds, and note that peripheral administration alters central serotonin and dopamine signalling.
TB-500, a synthetic fragment of thymosin beta-4, gets the same treatment: no human safety or efficacy trials exist for elective cosmetic or athletic use, and because thymosin beta-4 upregulates matrix metalloproteinases and promotes endothelial cell movement, the authors flag concern about the migration of occult tumour cells. They note the World Anti-Doping Agency prohibits it at all times.
On CJC-1295 and ipamorelin, the review concedes the mechanism is real – these compounds reliably raise growth hormone and IGF-1 – and then separates that from benefit. Evidence of meaningful improvement in muscle mass, athletic performance, body composition or healthy ageing remains limited, while the long-term concerns listed include glucose intolerance, fluid retention, peripheral oedema and growth promotion of an occult malignancy. Melanotan-II, a non-selective melanocortin agonist, is linked to rapid darkening of existing moles, atypical nevi and cutaneous melanoma, to acute rises in blood pressure and heart rate, and to rhabdomyolysis with kidney injury.
The supply chain is a separate risk from the molecule
The review’s second argument is about procurement rather than pharmacology, and it applies even to a compound that turns out to be harmless. Products bought from research-chemical suppliers are made outside current Good Manufacturing Practice requirements. Chemical analyses of direct-to-consumer peptide products, the authors write, have found significant deviations from stated dosages, truncated peptide impurities, and heavy metals or organic solvent residues. Because these products usually ship as freeze-dried powder for the buyer to reconstitute, bacterial endotoxin, inaccurate dosing and injection-site infection are added on top. They also note that the FDA has identified safety concerns for several nominated peptide bulk drug substances, BPC-157 and TB-500 among them, that their compounding status remains under review, and that neither is an approved therapy.
What is not yet known
This is a narrative review, not a systematic one. There is no stated search strategy, no pooled data and, crucially, no incidence for any harm described – the mechanisms are plausibility arguments built largely on preclinical work, and the honest verb throughout is could rather than does. Missouri Medicine is the journal of the Missouri State Medical Association; the authors report no financial disclosures. Nothing here tells a reader how likely any of these outcomes is, which is the question most people actually have. It tells them, with some precision, that nobody knows – and that the products themselves are frequently not what the label says.
Sources: Moiz A, O’Keefe EL, O’Keefe JH, “Dangers of Injectable Peptides and Other Unregulated Biohacking Drugs”, Missouri Medicine, July-August 2026, 123(4):337-343 (PMID 42757290). Full text read via PubMed Central (PMC13585006).
