Serious reactions to injected peptides: the conference cases

What happened in Las Vegas

On July 13, 2025, at the Revolution Against Aging and Death Festival (RAADFest), a longevity conference at a Las Vegas casino resort, two women received peptide injections at a booth in the event's exhibition hall. One was 38 and from California, the other 51 and from Nevada. Both left in ambulances, were hospitalised in critical condition and needed ventilators to breathe. They described feeling as if their tongues were swelling, with difficulty breathing and a racing heart; by the time they reached hospital, one was already intubated and the other had lost muscle control in her neck and could not open her eyes or communicate, according to the police report described by ProPublica ¹. Both recovered ¹.

The booth was run by a Los Angeles physician specialising in 'age reversal' therapies who was licensed in California but not in Nevada. According to the police report, a Nevada-licensed nurse practitioner injected one woman, and another practitioner who did not appear to hold Nevada licences mixed the vials and injected the other. The two women received different peptide combinations, and each included at least one component the FDA had described as posing significant risks when compounded ¹. Police initially said as many as seven people might have been hospitalised; detectives could not confirm any beyond the two ¹.

What the investigation found, and what it didn't

In early 2026 the Nevada Board of Pharmacy issued its citations. It fined the doctor and a pharmacist, both licensed in California, $10,000 each for practising in Nevada without a licence; fined an 'integrative health coach' who did not appear to hold any health care licence $5,000 for recommending or prescribing one of the peptide cocktails; and fined a Texas-based private membership association $10,000 for what it called unlicensed wholesaling, alleging the group had mailed the peptides to the resort marked for the doctor's attention. The association denied supplying them for public use ².

The central question was never answered. The board could not determine why the women became ill, including whether the injections were contaminated or the women had reacted to the peptides themselves, because investigators were unable to obtain the product to test it ². That is the most important lesson of the case. When a reaction follows an injection of an unapproved product, there is often no lot number to trace, no manufacturer to recall from, no label to consult and no sample left to analyse.

What FDA had already said about these peptides

The FDA keeps a public list of bulk substances it has found may present significant safety risks in compounding, known as Category 2. As of the version current on April 22, 2026, GHRP-2, GHRP-6, ipamorelin Medium, kisspeptin-10 and ibutamoren were in it, and a second table listed substances previously in Category 2 whose nominations were withdrawn, including BPC-157 Low, MOTS-c Low, the thymosin beta-4 fragment sold as TB-500, CJC-1295 Medium and melanotan II Low, with FDA's risk statements kept beside each ³.

Those statements repeat one concern again and again: compounded versions may pose a risk of immunogenicity, an immune response to the drug, because of the potential for aggregation and peptide-related impurities, alongside complexities in characterising the active ingredient. For most of them FDA adds that it has little or no human safety information. For some it names specific harms: increased heart rate and a systemic vasodilatory reaction with CJC-1295; deaths among serious adverse events in an intravenous ipamorelin study; and published case reports of melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxicity and priapism with melanotan II ³. Our PCAC hub follows the committee's July 2026 votes on seven of these peptides and FDA's response.

FDA's concerns, peptide by peptide

The table summarises FDA's own risk statements for the peptides most often sold for longevity, body composition and recovery, as they appeared on the agency's page current as of April 22, 2026 ³. A withdrawn nomination means the substance is no longer under review for the compounding bulks list through that nomination; it is not a finding of safety, and FDA kept its risk statement on the page.

Two things stand out. Immunogenicity is the common thread, which fits the kind of reaction the RAADFest patients had, though no one has shown that it caused theirs. And most entries say, in one form or another, that FDA lacks the information to know whether the substance would cause harm in people ³. That is a statement about missing evidence, and anyone injecting these products is supplying the missing experiment on themselves.

How an injected peptide can trigger an immune reaction

Peptides are small, and most are not strongly immunogenic, but the risk is not zero and it rises with impurities. Synthesis can produce peptides with an extra, missing or modified amino acid, and those variants can create new targets for the immune system. FDA scientists and collaborators have studied exactly this for generic synthetic peptides: in salmon calcitonin, impurities were assessed as having slightly more or less immune risk than the drug itself ⁴, and in teriparatide, several impurities were more immunogenic than the active peptide ⁵. That is why approved generics must keep each impurity below set limits and test any new one ⁵.

A research vial has no such limits. Aggregates, clumps of peptide that form during manufacture or storage, are another trigger FDA names ³. And the immune system is not the only route to an acute reaction: bacterial endotoxin causes fever, rigors and shock, and it was found in every semaglutide vial in one study of illegal online sellers ⁶. Our guide to the contaminants a COA rarely shows covers endotoxin, sterility and the rest.

Even approved peptides can cause anaphylaxis

Severe allergic reactions happen with properly made drugs too. A 2026 case report describes a 37-year-old woman who developed anaphylaxis, with facial swelling, hives, bronchospasm, low oxygen and low blood pressure, shortly after her first known dose of tirzepatide, needing two doses of adrenaline and with a possible second wave about an hour later ⁷. Immediate allergic reactions to exenatide have been severe enough that allergists developed a desensitisation protocol for patients who had no alternative ⁸.

These reactions are rare, and their labels warn about them. The point is not that peptides are uniquely dangerous; it is that any injected drug can cause anaphylaxis, which is treatable when it happens somewhere with adrenaline, oxygen and trained staff. An emergency physician who spoke at RAADFest made exactly this point to ProPublica: even the most benign intervention can have fatal side effects, and a hotel without lifesaving equipment nearby is a risk in itself. She also noted that the women's symptoms sounded allergic, and cautioned that the agents drugs are mixed with before injection can sometimes cause problems ¹.

Other serious harms reported with unapproved peptides

Acute reactions are only one kind of harm. Melanotan II, sold for tanning, has case reports of a renal infarction most likely attributed to it, alongside previously described rhabdomyolysis and kidney failure ⁹, and of low-flow priapism needing emergency treatment, with erectile function not recovered four weeks later ¹⁰. Contamination at scale has a history too: in 2012 contaminated steroid injections from a single US compounding pharmacy caused a nationwide outbreak of fungal meningitis ¹¹. That pharmacy was a regulated business; research-chemical sellers are not.

What the cases teach

Five lessons follow, none of them new. Licensing matters: Nevada requires out-of-state doctors at events to hold a special event licence, and to dispense drugs, a pharmacy licence ¹. Setting matters: a severe reaction needs adrenaline, airway equipment and people trained to use them, within minutes. Provenance matters: without a lot number and a retained sample, no one could test what the women received ². Mixing matters: combining several unapproved peptides in one injection multiplies the unknowns and makes it impossible to tell which caused a reaction. And absence of evidence is not safety: for most of the peptides involved, FDA says it has little or no human safety data ³.

If you develop swelling of the lips, tongue or throat, difficulty breathing, wheezing, faintness or a racing heart after any injection, call emergency services. If you used a product with a lot number, keep the vial; it may be the only way anyone can find out what happened.

Frequently asked questions

What happened at RAADFest with peptides?

On July 13, 2025, two women became critically ill and needed ventilators after peptide injections at a booth at the Las Vegas longevity festival. Both recovered. Nevada later fined four parties, but investigators could not obtain the product and never determined the cause.

Can peptide injections cause allergic reactions?

Yes. FDA's main stated concern about many compounded peptides is immunogenicity from aggregates and impurities, and even approved peptide drugs such as tirzepatide and exenatide have caused severe allergic reactions in rare cases.

Which peptides does FDA list as safety risks?

As of April 22, 2026, FDA's Category 2 list included GHRP-2, GHRP-6, ipamorelin, kisspeptin-10 and ibutamoren; BPC-157, MOTS-c, TB-500, CJC-1295 and melanotan II appeared in a table of withdrawn nominations, with FDA's risk statements kept.

What should I do if I react to an injection?

Call emergency services for swelling of the lips, tongue or throat, trouble breathing, wheezing, faintness or a racing heart. Keep the vial and its lot number.

Related on Grey Peptides

• Verify hub
• PCAC July 2026 hub
• Contaminants a COA rarely shows

Sources

1. Damon, A. (2025). A Las Vegas Festival Promised Ways to Cheat Death. Two Attendees Left Fighting for Their Lives. ProPublica, July 29, 2025 (updated March 9, 2026). Read October 3, 2026.
2. Damon, A. (2026). Nevada Regulators Fine Peptide Providers at Anti-Aging Festival Where Two Women Became Critically Ill. ProPublica, March 13, 2026. Read October 3, 2026.
3. FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Category 2 and withdrawn nominations). Content current as of April 22, 2026; read October 3, 2026. FDA
4. Roberts, B. J., et al. (2024). Assessing the immunogenicity risk of salmon calcitonin peptide impurities using in silico and in vitro methods. Front Pharmacol, 15, 1363139. PMID: 39185315
5. Mattei, A. E., et al. (2025). Immunogenicity risk assessment of peptide-related impurities identified in generic teriparatide products. Front Immunol, 16, 1730346. PMID: 41445733
6. Ashraf, A. R., et al. (2024). Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription: Market Surveillance, Content Analysis, and Product Purchase Evaluation Study. J Med Internet Res, 26, e65440. PMID: 39509151
7. Al-Rashid, A. H., et al. (2026). Suspected Biphasic Anaphylaxis Following the First Known Dose of Tirzepatide: A Case Report and Brief Review of Reported Hypersensitivity Reactions. Cureus, 18(8), e113910. PMID: 42694337
8. Yeğit, O. O., et al. (2023). The first successful desensitization protocol in exenatide allergy: a case report. Allergy Asthma Clin Immunol, 19(1), 2. PMID: 36639791
9. Peters, B., et al. (2020). Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN Case Rep, 9(2), 159-161. PMID: 31953620
10. Dreyer, B. A., et al. (2019). Melanotan-induced priapism: a hard-earned tan. BMJ Case Rep, 12(2). PMID: 30796078
11. McCarthy, M. W., et al. (2017). Molecular diagnosis of invasive mycoses of the central nervous system. Expert Rev Mol Diagn, 17(2), 129-139. PMID: 27936983

Educational information, not medical advice. Each dose in this guide names its source, an approved label or a published study. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose.