VIP

VIP is a 28-amino-acid endogenous neuropeptide of the secretin/glucagon superfamily, produced by neurons and immune cells throughout the gut, lungs and nervous system. It signals through the G-protein-coupled receptors VPAC1 and VPAC2 (and shares PAC1 with the related peptide PACAP), predominantly raising intracellular cAMP. Physiologically it drives smooth-muscle relaxation and vasodilation, stimulates secretion, and helps set circadian rhythm in the suprachiasmatic nucleus. It is also a broad immunomodulator: acting on macrophages, T cells and other leukocytes it generally shifts responses toward an anti-inflammatory, tolerogenic profile, reducing pro-inflammatory cytokines. Aviptadil is the synthetic pharmaceutical form of the identical peptide. Because native VIP is rapidly degraded in plasma, it is not orally active and its effects are short-lived.

VIP is very well characterised as an endogenous signalling peptide; Delgado et al. (2004) is a foundational review of its immunomodulatory biology. As a therapeutic, the synthetic form aviptadil has been the main clinical test case, primarily in acute respiratory failure. Here the evidence is largely negative: the large NIH-sponsored randomised, placebo-controlled TESICO trial (Brown et al., 2023) found intravenous aviptadil did not significantly improve outcomes in COVID-19-associated respiratory failure. VIP/aviptadil is not an approved general medicine, and human use to date has occurred within monitored clinical trials.

Educational overview only — no dosing instructions in the public hub.

As a potent vasodilator, VIP/aviptadil infusion can cause hypotension, flushing, tachycardia and diarrhoea; the human safety data available come from monitored hospital trials with intravenous administration, not from general or unsupervised use. Given rapid plasma degradation and the negative pivotal trial, a favourable benefit-risk for non-approved uses is not established. Long-term and non-clinical safety are unknown.

A third-party CoA covering identity, purity (HPLC) and mass confirmation (MS) is the minimum verification. A 28-residue peptide is prone to synthesis-related impurities and to rapid degradation, so both purity and quantification matter, as does careful reconstitution and storage.

Not approved as a general medicine. The synthetic form (aviptadil) is investigational; outside authorised clinical trials it is treated as research-use-only in most jurisdictions and is not approved by the FDA or EMA for routine human use.