Vasopressin: what the evidence shows

What the human research shows

An approved medicine whose main trial was negative — and which is still used, because reducing the catecholamine dose is a legitimate goal even when mortality does not move. Grade A throughout: the trials are large and the answers are clear, including the answer "no difference".

Evidence profile0–5

Metabolic & weight—0.0
Cardiovascular—0.0
Muscle & growth—0.0
Healing & repair—0.0
Neuro & sleep—0.0
Immune & inflammation—0.0
Sexual & hormonal—0.0
Skin & appearance—0.0
Ageing & longevity—0.0

No benefit outcome for Vasopressin has both human evidence and a measurable effect, so the profile is empty. That is the finding, not a gap in the chart.

Outcome	Grade	Effect size	Human studies	Where the evidence comes from
Mortality in septic shock	AEstablished	Not measurable	1 large RCT (VASST, n=778)	VASST randomised 778 patients with septic shock to vasopressin or noradrenaline infusion in addition to open-label vasopressors. There was no difference in 28-day or 90-day mortality. A large, well-conducted negative trial, and the reason vasopressin is a catecholamine-sparing adjunct rather than a survival intervention.1
Raising blood pressure in vasodilatory shock	AEstablished	Moderate	Approval programme; label	The licensed indication. Vasopressin raises mean arterial pressure through V1 receptors on vascular smooth muscle by a pathway independent of the adrenergic receptors, which is why it works when catecholamines are failing and why it lets their dose come down.2
Serious adverse eventsadverse	AEstablished	Not measurable	1 large RCT (VASST, n=778)	In VASST serious adverse events occurred at the same rate in both arms. The clinically watched risks — digital and mesenteric ischaemia from intense vasoconstriction — did not separate the groups at the doses studied.1
Water retention and low sodiumadverse	AEstablished	Moderate	Label; the desmopressin literature	V2 receptor activation in the kidney is the antidiuretic effect, and its consequence is dilutional hyponatraemia — the harm that defines the whole vasopressin family, and the reason its analogue desmopressin carries a sodium warning in older patients.2

AMultiple good human trials, consistentBSome human trials, mostly consistentCFew or weak human studiesDAnimal or anecdotal onlyeffect size · red = adverse

Literature searched to 29 October 2026. Human studies only; animal and cell work informs the mechanism section and nothing else.

Registered trials

ClinicalTrials.gov lists 18 interventional studies naming Vasopressin as an intervention — 7 completed, 6 recruiting, and none with results posted to the registry.

A registration is not a result. Anyone can register a study, and many never report — so this list shows what has been attempted, not what has been shown. The graded evidence above is the answer to whether something works.

Study	Phase	Status	Participants	Sponsor	Results
Vasopressin for Septic Shock Pragmatic TrialNCT06217562 · started Feb 2024	Phase 4	Completed	3,959	Intermountain Health Care, Inc.	None
Early Versus Late Adjunctive Vasopressin in Septic ShockNCT06709573 · started Apr 2025	Phase 4	Recruiting	300*	The Cleveland Clinic	None
Renal Outcomes in the Early Use of Vasopressin in the Treatment of Septic ShockNCT06471231 · started May 2024	Phase 4	Unknown	264*	Azienda Usl di Bologna	None
NOrepinephrine and VasoprEssin Versus Norepinephrine aLone in Critically Ill Patients With Septic ShockNCT02454348 · started Nov 2015	Phase 4	Withdrawn	0	University of Arkansas	None
Angiotensin II vs. Vasopressin in Septic ShockNCT05193370 · started Jan 2022	Phase 4	Withdrawn	0	University of New Mexico	None
Norepinephrine and Vasopressin for Rescue Versus Early Vasopressin for Vasopressor Dependent SepsisNCT06464510 · started Nov 2024	Phase 3	Recruiting	2,800*	Hospital do Coracao	None
VAsopressin and STeroids in Addition to Adrenaline in Cardiac Arrest - a Randomized Clinical TrialNCT05139849 · started Nov 2021	Phase 3	Recruiting	1,276*	Tiohundra AB	None
Vasopressin Versus Norepinephrine for the Management of Septic Shock in Cancer PatientsNCT01718613 · started Nov 2012	Phase 3	Completed	250	Instituto do Cancer do Estado de São Paulo	None

10 further studies are registered. Participant counts marked * are the sponsor's estimate, not a final enrolment. Source: ClinicalTrials.gov, read directly from the registry and refreshed weekly.

What it is

Vasopressin is a nine-residue cyclic peptide made in the hypothalamus and released from the posterior pituitary, with a disulfide bridge between residues 1 and 6. Two receptor families explain everything it does: V1 on vascular smooth muscle, which constricts vessels, and V2 in the kidney's collecting ducts, which retains water. The Vasostrict label gives the structure as cyclo(1-6)Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH2.

Its therapeutic descendants are on this site already: desmopressin is vasopressin re-engineered to keep the water effect and drop the vascular one. Vasopressin itself is a hospital drug given by infusion with continuous monitoring, and has no grey-market presence — which is the point of including it.

How it is thought to work

V1 receptor activation raises intracellular calcium in vascular smooth muscle and constricts arterioles, independently of alpha-adrenergic signalling — the property that makes it useful when noradrenaline alone is not holding blood pressure. V2 receptors insert aquaporin channels into the collecting duct, concentrating urine. Its apparent half-life is minutes, so the effect is titrated by infusion rate and disappears quickly when the infusion stops.

What is still unknown

Whether earlier initiation, or particular subgroups, would show a mortality benefit; VASST's subgroup signals were not confirmed.
The optimal place of vasopressin relative to other second-line vasopressors.

The molecule and how long it lasts

Identity

Formula: C46H65N15O12S2
Molecular weight: 1084.2 g/mol
CAS number: 113-79-1
PubChem: CID 644077
Sequence: CYFQNCPRG-NH2

One disulfide bridge, Cys1-Cys6.

Recorded as argipressin, the human (arginine) form

PubChem record, read 29 October 2026; the sequence was derived from that record's own structure and checked against the product label where one exists.

Pharmacokinetics

Route: Intravenous infusion (hospital use)
Half-life: Apparent half-life no more than 10 minutes
Licensed regimen (Vasostrict): A continuous infusion started at a low rate and titrated to the target blood pressure, in monitored care

From the approved product's prescribing information: Vasostrict prescribing information (DailyMed) The regimen is the label's own wording, reproduced as a regulatory fact.

Regulatory status

European Union

Authorised nationally, hospital use

Argipressin products authorised in several member states for vasodilatory shock and diagnostic use.

United States

Approved, prescription-only

Vasostrict approved to increase blood pressure in adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines. Intravenous infusion, hospital use.

United Kingdom

Licensed, hospital use

Argipressin licensed for vasodilatory shock.

Australia

Registered, Schedule 4

Registered for hospital use.

Canada

Authorised, prescription-only

Vasopressin injection authorised with a Drug Identification Number.

Sport (WADA)

Not prohibited as such

Vasopressin itself is not named; its analogue desmopressin is prohibited as a masking agent (S5), and plasma expanders and masking agents are the relevant category.

Questions people actually ask

Does vasopressin save lives in septic shock?

Its largest randomised trial, in 778 patients, found no difference in 28-day or 90-day mortality against noradrenaline. It is used to raise blood pressure and reduce the catecholamine dose, which is a different claim from improving survival.

Is vasopressin the same as desmopressin?

No. Desmopressin is a modified version that keeps the kidney (V2) effect and largely loses the blood-vessel (V1) effect, which is why it treats diabetes insipidus and bedwetting while vasopressin is a vasopressor.

Why is it only used in hospital?

Its half-life is minutes, it is given by continuous intravenous infusion, and the dose is titrated against arterial pressure. There is no formulation or circumstance in which it is used outside monitored care.

One page per claimed effect

ADoes Vasopressin help with mortality in septic shock?1 large RCT (VASST, n=778)
ADoes Vasopressin help with raising blood pressure in vasodilatory shock?Approval programme; label
AHow common is serious adverse events with Vasopressin?1 large RCT (VASST, n=778)
AHow common is water retention and low sodium with Vasopressin?Label; the desmopressin literature

References

1
Russell JA, Walley KR, Singer J, et al. Vasopressin versus norepinephrine infusion in patients with septic shock (VASST).N Engl J Med, 2008;358:877–887778 randomised; no difference in 28-day or 90-day mortality.
2
Vasostrict (vasopressin injection) prescribing information.DailyMed, read 29 Oct 2026Intravenous infusion; apparent half-life under 10 minutes; indication in vasodilatory shock; chemical structure.
3
PubChem compound record: argipressin (vasopressin).PubChem, read 29 Oct 2026Formula, molecular weight, CAS and the nine-residue sequence used on this page.

Change log

2026-10-29Initial publication. Grade A throughout, including the negative mortality row from VASST.