Aviptadil (synthetic VIP) is investigational and has no FDA approval. This page summarises safety information from published trials and clinical medicine. It is educational and does not replace evaluation by a qualified clinician.
Overview
VIP is unusual among the peptides on this site because its risk profile can be reasoned about from two independent directions. The first is its trial record. The second is rarer and more revealing: there is a human disease of VIP excess. VIPoma, a neuroendocrine tumour that secretes VIP without regulation, produces a recognisable clinical syndrome — and that syndrome is essentially a description of what unopposed VIP signalling does to a person.
What the trials recorded
The largest randomised trial of intravenous aviptadil provides the only substantial controlled safety dataset. In TESICO, 461 patients with COVID-19-associated hypoxaemic respiratory failure received aviptadil (n=231) or placebo (n=230) as daily 12-hour infusions over three days. The composite primary safety outcome — death, serious adverse events, organ failure, serious infection, or grade 3 or 4 adverse events by day 5 — occurred in 146 of 231 (63%) on aviptadil versus 129 of 230 (56%) on placebo (odds ratio 1.40, 95% CI 0.94–2.08, p=0.10) (Brown et al., Lancet Respir Med 2023).
That difference did not reach statistical significance, and the population was critically ill, which makes attribution difficult. But it is a numerically higher rate in the treated arm, in a trial that also found no efficacy benefit and was stopped for futility — a combination worth stating rather than smoothing over.
A smaller trial of inhaled aviptadil in 80 hospitalised patients reported good tolerability with no treatment-related dropouts (Esendagli et al., Med Princ Pract 2025) — a plausible difference, since inhaled delivery targets the lung rather than flooding the circulation.
The VIPoma lesson — what excess VIP does
VIPoma is a rare, mostly malignant neuroendocrine tumour characterised by watery diarrhoea, hypokalaemia and achlorhydria, caused by unregulated increased secretion of VIP. Primary management includes fluid replacement and correction of electrolyte imbalance before anything else (Karele, Presse Med 2024).
This is the most useful safety fact available about the molecule, because it describes sustained excess in humans rather than a single infusion. Secretory diarrhoea severe enough to cause potassium depletion is not a theoretical concern imported from a receptor map; it is the defining feature of the human syndrome of too much VIP. Nobody has established what exposure level from exogenous VIP would approach that territory, and the absence of that threshold is itself the point.
Effects predictable from the pharmacology
VIP is a potent vasodilator acting through VPAC receptors and cyclic AMP, so a predictable cluster of effects follows directly from mechanism:
- Flushing and warmth, the classic marker of rapid vasodilation.
- Reduced blood pressure with reflex tachycardia — the reason the studied intravenous protocols are hospital infusions with monitoring rather than bolus injections.
- Headache, which commonly accompanies vasodilation.
- Gastrointestinal effects including loose stools, consistent with VIP's secretory role in the gut and with the VIPoma picture above.
- Route-specific local effects, such as nasal irritation with intranasal preparations.
Interactions with antihypertensives, vasodilators, and cardiovascular medications have not been formally characterised, which is a gap rather than a reassurance given the overlap in mechanism.
What is unknown about unsupervised use
Every safety observation above comes from a monitored setting: hospital infusions with vital-sign monitoring, or a diagnosed tumour under specialist care. Intranasal VIP obtained from compounding sources or research suppliers for chronic self-administration sits entirely outside that evidence.
Specifically unknown: what happens with repeated dosing over months, whether chronic VPAC receptor stimulation produces tolerance or downstream changes, what cardiovascular effect accumulates in someone not being monitored, and what a given unverified preparation actually contains. VIP is also degraded quickly in the body, so preparation stability and storage are practical variables on top of everything else. Broader context is in what are the risks of peptides.