Peptide Basics
Vasopressin (ADH): The Antidiuretic Peptide Hormone, Its Three Receptors and the Medicines Built on It
Vasopressin, also called antidiuretic hormone (ADH), is a nine-amino-acid peptide released from the posterior pituitary. It makes the kidney hold on to water and narrows blood vessels. This page sets out what the molecule is, the precursor it is cut from, how it compares with its sister hormone oxytocin, the three receptors it acts on and the vasopressin medicines in FDA’s records. Every figure is taken from UniProt, PubChem, MeSH or FDA’s own databases and labels.
What vasopressin is
Vasopressin is one of the peptide hormones. MeSH, the U.S. National Library of Medicine’s subject index, describes the vasopressins as antidiuretic hormones released by the neurohypophysis, the posterior pituitary, that regulate water balance and the concentration of body fluids. Acting on the collecting ducts of the kidney, vasopressin increases water reabsorption, blood volume and blood pressure.
In humans the hormone is arginine vasopressin, which MeSH calls the predominant form of mammalian antidiuretic hormone. It is a nonapeptide, nine amino acids, with an arginine at position 8 and two cysteines, at positions 1 and 6, joined by a disulfide bond. All mammals have arginine vasopressin except the pig, which has lysine at position 8.
The human sequence reads CYFQNCPRG, with an amide on the final glycine. PubChem gives it a molecular formula of C46H65N15O12S2 and a molecular weight of 1,084.2 (CID 644077, argipressin). It is also one of the neuropeptides: it is made in the hypothalamus and released from the posterior pituitary.
The precursor: vasopressin, neurophysin 2 and copeptin
Vasopressin is made as part of a precursor of 164 amino acids. UniProt records that the precursor is cut by enzymes such as the convertases PC1 and PC2, and that an enzyme called PAM then adds the amide to the hormone’s last glycine, which completes its activation. The carrier protein, neurophysin 2, binds vasopressin and transports it from the hypothalamus to the posterior pituitary, protecting it from breakdown. The pieces, by position:
| Piece | Positions | Amino acids | Note |
|---|---|---|---|
| Signal peptide | 1-19 | 19 | Steers the precursor into the secretory pathway; removed first. |
| Arginine vasopressin | 20-28 | 9 | The hormone. Finished with an amide on its last glycine. |
| Neurophysin 2 | 32-124 | 93 | Its carrier: holds vasopressin on the way from the hypothalamus to the posterior pituitary. |
| Copeptin | 126-164 | 39 | The tail end of the precursor, cut from the same molecule as the hormone. |
The first piece is a signal sequence, explained on our signal peptides page. UniProt links variants of this gene to neurohypophyseal diabetes insipidus.
Source: UniProt P01185 (AVP). Read 4 November 2026.
Vasopressin vs oxytocin
Vasopressin and oxytocin are the two hormones of the posterior pituitary, and as molecules they are close relatives: same length, same ring, two amino acids apart. Their precursors are built the same way, each with its own neurophysin.
| Vasopressin | Oxytocin | |
|---|---|---|
| Sequence | CYFQNCPRG-amide | CYIQNCPLG-amide |
| Length and shape | 9 amino acids; a six-residue ring closed by a disulfide between cysteines 1 and 6 | The same |
| Where they differ | Phenylalanine at 3, arginine at 8 | Isoleucine at 3, leucine at 8 |
| Molecular weight (PubChem) | 1,084.2 | 1,007.2 |
| Precursor and carrier | 164 amino acids; neurophysin 2 | 125 amino acids; neurophysin 1 |
| Receptors | V1a, V1b and V2 | The oxytocin receptor, OXTR |
| Main roles UniProt records | Water retention by the kidney; narrowing of blood vessels | Social behaviour; milk ejection |
Our oxytocin guide covers that compound’s identity, research history and regulatory record.
Sources: UniProt P01185 and P01178; PubChem CID 644077 and 439302. Read 4 November 2026.
The three vasopressin receptors
UniProt records that vasopressin acts by binding three receptors, V1a, V1b and V2. All three are G protein-coupled receptors that cross the cell membrane seven times, but they pass the signal on in different ways:
| Receptor (gene) | Amino acids | Signal inside the cell | What UniProt records |
|---|---|---|---|
| V1a (AVPR1A) | 418 | Phosphatidylinositol-calcium pathway | UniProt also notes a role in social behaviours, including affiliation and attachment. |
| V1b (AVPR1B) | 424 | Phosphatidylinositol-calcium pathway | Recorded as a vasopressin receptor using the same pathway as V1a. |
| V2 (AVPR2) | 371 | Gs protein, adenylate cyclase, cyclic AMP | Found in the kidney; makes the kidney take water back. Variants cause X-linked nephrogenic diabetes insipidus. |
The split explains the hormone’s two names. Its effect on water, the antidiuretic effect, runs through V2 in the kidney; its effect on blood vessels, the pressor effect, is the vasoconstriction UniProt records for the hormone. Medicines built on vasopressin differ mainly in which receptors they favour.
Sources: UniProt P01185, P37288, P47901 and P30518. Read 4 November 2026.
Vasopressin medicines: what FDA’s records show
Drugs@FDA holds records for vasopressin itself, for three peptide analogues and for two small molecules that block its receptors. The table gives the earliest approval year the database records for each, and what the current U.S. label says the product is and is for:
| Medicine | Applications | First approved | What the record and label show |
|---|---|---|---|
| Pitressin Tannate (Parke-Davis) | NDA 003402 | — | The oldest vasopressin record in Drugs@FDA; the database gives it no approval date. Discontinued. |
| Vasopressin (Vasostrict and others) | NDA 204485 and later | 2014 | Synthetic arginine vasopressin; labelled to raise blood pressure in adults with vasodilatory shock that persists despite fluids and catecholamines. |
| Desmopressin (DDAVP and others) | NDA 017922, 018938, 019955, 219873 | 1978 | A synthetic analogue; labels name central diabetes insipidus, and the injection also haemophilia A and type I von Willebrand disease. |
| Terlipressin (Terlivaz) | NDA 022231 | 2022 | A 12-amino-acid analogue that also acts as a prodrug of lysine vasopressin; labelled to improve kidney function in hepatorenal syndrome. |
| Lypressin (Diapid) | NDA 016755 | — | Lysine vasopressin as a nasal solution; discontinued. |
| Tolvaptan (Samsca, Jynarque) | NDA 022275, 204441 | 2009 | Not a peptide: a small-molecule V2 blocker, labelled for low blood sodium (Samsca) and to slow kidney decline in ADPKD (Jynarque). |
| Conivaptan (Vaprisol) | NDA 021697 | 2005 | Not a peptide: a small molecule that ChEBI, via PubChem, describes as blocking two of the three receptors, V1a and V2. |
Desmopressin shows how a small change moves a peptide between receptors. MeSH records that it acts through V2 with a prolonged antidiuretic effect and little effect on blood pressure, and that it also changes blood levels of clotting factor VIII and von Willebrand factor. Terlipressin goes the other way: its label describes twice the selectivity for V1 receptors over V2. Selepressin, another analogue listed in PubChem, had no Drugs@FDA record when searched on 4 November 2026.
Sources: Drugs@FDA via openFDA (original approval dates and marketing status); current U.S. labels for Vasostrict, DDAVP injection, Desmoda, Terlivaz, Samsca and Jynarque; MeSH D003894; PubChem CID 5311065, 72081, 644076, 53330936, 216237 and 151171. Read 4 November 2026. Doses are not reproduced here.
Medibact does not manufacture or sell peptides. We supply USP-grade bacteriostatic water, made in the USA, for research use only, and publish reference material like this page.
Where this sits in the rest of the reference
FAQ
What is vasopressin?
Vasopressin is a peptide hormone of nine amino acids, also called antidiuretic hormone (ADH). It is made in the hypothalamus, carried down nerve fibres by its carrier protein and released from the posterior pituitary. UniProt records that it acts directly on the kidney to hold back water and narrows peripheral blood vessels. MeSH calls arginine vasopressin the predominant form of mammalian antidiuretic hormone.
Is vasopressin the same as ADH?
Yes. Antidiuretic hormone is the name for what the hormone does: it reduces the amount of water lost in urine. In humans and most mammals the antidiuretic hormone is arginine vasopressin. MeSH records that the pig is the exception, with lysine instead of arginine at position 8.
Is vasopressin a peptide or a protein?
A peptide. Arginine vasopressin is nine amino acids, CYFQNCPRG with an amide at the end, and PubChem gives it a molecular weight of 1,084.2 (CID 644077). Two cysteines, at positions 1 and 6, are joined by a disulfide bond, which closes the first six amino acids into a ring. It is cut from a precursor of 164 amino acids.
What is the difference between vasopressin and oxytocin?
They are sister hormones. Both are nine amino acids long, both have the same six-residue ring and both are released from the posterior pituitary. They differ at only two positions: vasopressin has phenylalanine at 3 and arginine at 8, oxytocin has isoleucine at 3 and leucine at 8. Vasopressin acts on the V1a, V1b and V2 receptors; oxytocin acts on its own receptor, OXTR.
What do the vasopressin receptors do?
There are three, all G protein-coupled receptors. UniProt records that V1a and V1b work through the phosphatidylinositol-calcium pathway, and that V1a has been linked to social behaviours. V2, found in the kidney, couples to Gs proteins, raises cyclic AMP and makes the kidney take water back into the body. Variants of the V2 gene cause X-linked nephrogenic diabetes insipidus.
What is copeptin?
Copeptin is the last 39 amino acids of the vasopressin precursor (positions 126 to 164 in UniProt P01185). The precursor is cut into vasopressin, its carrier neurophysin 2 and copeptin, so copeptin is released from the same molecule as the hormone.
What is desmopressin?
Desmopressin is a synthetic analogue of vasopressin, also written dDAVP: the first amino group is removed and the arginine at position 8 is in the D form. MeSH records that it acts on the V2 receptor, with prolonged antidiuretic activity and little effect on blood pressure. FDA first approved it in 1978 as DDAVP, a nasal product; current labels name central diabetes insipidus and, for the injection, haemophilia A and type I von Willebrand disease.
What is vasopressin used for as a medicine?
In the United States, vasopressin injection is labelled to raise blood pressure in adults with vasodilatory shock who stay hypotensive despite fluids and catecholamines. Its earliest dated approval in Drugs@FDA is Vasostrict, NDA 204485, from 2014; an older record, Parke-Davis's Pitressin Tannate (NDA 003402), carries no approval date and is discontinued. Several other makers have approvals since 2020. Its label describes the product as synthetic arginine vasopressin.
Is this medical advice?
No. This page explains what vasopressin is, from public scientific and regulatory sources. It gives no dose, schedule or recommendation; anyone treated with these medicines should follow their own clinician and product label. Peptides sold for research are labelled research use only, not for human use. Medibact supplies USP-grade bacteriostatic water, made in the USA, and is not affiliated with any manufacturer of the products named here.
References: UniProt P01185, P01178, P37288, P47901, P30518; MeSH D001127, D014667, D003894; PubChem CID 644077, 439302, 5311065, 72081; Drugs@FDA via openFDA and the current U.S. labels named above. Read 4 November 2026.
Educational use only — not medical advice. This guide summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.