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Compound guide
VIP: what the research covers
Vasoactive intestinal peptide was named for the first thing anyone noticed it doing. Twenty-eight residues later it turned out to be a neurotransmitter, an immune regulator and a circadian signal as well.
What VIP is
VIP is a twenty-eight residue peptide of the glucagon-secretin superfamily, which places it in the same structural family as GHRH and PACAP. It was isolated from intestinal tissue and named for its vasodilatory effect, a description that has aged poorly given how much else it does.
It acts at two class-B G-protein-coupled receptors, VPAC1 and VPAC2, both coupling principally to Gs and cyclic AMP. The receptors have different tissue distributions, and the compound itself does not distinguish between them — which is why selective analogues exist and why VIP is usually the non-selective reference in work that needs the distinction made.
In the body it functions as a neurotransmitter in the enteric and central nervous systems, as a regulator of secretion and smooth muscle tone, as an immune modulator, and as the principal signalling peptide coordinating neurons of the suprachiasmatic nucleus — the circadian pacemaker.
Why it appears in immunology and in chronobiology
The immunological literature treats VIP as an endogenous anti-inflammatory signal: it shifts cytokine profiles away from the inflammatory pattern, influences regulatory T cell populations and dampens macrophage activation. That strand overlaps with the repair peptides in this group, though VIP arrives at the same territory through a receptor system none of them use.
The circadian literature is separate and does not translate across. VPAC2 signalling is required for the suprachiasmatic nucleus to maintain a coherent rhythm, and VIP-deficient animals show disorganised rather than merely shifted rhythms. An experiment using VIP in one of these fields should be read against that field, since the receptor, tissue and concentration ranges differ.
Within this catalogue, DSIP is the other compound with a sleep and rhythm literature, though by an entirely different and much less well characterised route.
How Amino Club supplies it
Supplied lyophilised in sealed vials as VIP, specified at 99% purity or better by HPLC with identity confirmed by mass spectrometry and released against the batch Certificate of Analysis. The lab testing page documents how that is done.
VIP is among the less stable peptides in this catalogue in aqueous solution, being readily cleaved by peptidases and sensitive to oxidation at its methionine residue. Laboratories hold the dry powder below −18 °C, prepare small single-use working volumes, keep them cold and dark, and avoid repeated freeze-thaw cycles. Diluents are listed under reconstitution supplies.
Related reading
VIP belongs to the tissue repair research peptides group with BPC-157, TB-500, ARA-290, KPV and LL-37. Its circadian literature connects it to the cognitive and sleep group.
Every guide is indexed in the research library. Certificates and storage are covered on the FAQ, quantity pricing through bulk and wholesale.
Research use only
VIP supplied by Amino Club is a laboratory reference material. It is not a medicine, not a supplement, and not for human or veterinary use, and no dosing guidance or administration protocol is provided. The full terms are in the research use policy.