Oxytocin 5 mg vial dosage

What Oxytocin is

Class:

Nine-amino-acid peptide hormone

Also called:

Pitocin, Syntocinon

Used for:

An approved injectable medicine in obstetrics. Sold online as a nasal spray for libido, connection and anxiety.

Human evidence:

Moderate human evidence. Seventy-one randomised trials of intranasal oxytocin, in autism spectrum conditions, obesity and social cognition. A search for randomised trials of intranasal oxytocin in erectile function, libido or sexual function returned none. The rating covers the intranasal research literature, which is not about the marketed use.

Half-life:

About 1 to 6 minutes in plasma, shorter in late pregnancy and during breastfeeding, per the Pitocin label.

US status:

FDA-approved · prescription only. Injectable oxytocin is an approved prescription medicine used in obstetrics under clinical supervision; Pitocin is the US brand currently marketed. Syntocinon, both the injection and a nasal spray, was once FDA-approved but is listed as discontinued in Drugs@FDA, and no oxytocin nasal spray is currently approved in the US. Intranasal oxytocin sold for libido, connection or anxiety is not an approved product for that purpose.

The full picture, with every study: Oxytocin guide.

How to mix a 5 mg Oxytocin vial

For this vial: 1 mL of bacteriostatic water makes 5 mg/mL, so 300 mcg is 6 units (0.06 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

1. Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. ^[3][4]
2. With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. ^[3][4][5]
3. Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. ^[6]
4. Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. ^[3][4][6]
5. Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. ^[3]
6. Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. ^[6]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing Oxytocin vials

• Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. ^[7]
• Protect peptide vials from heat and light. ^[7][8]
• Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. ^[6][7]
• Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. ^[9][10]

More detail: peptide storage and shelf life.

Injecting safely

• Clean the injection site with an alcohol swab and let the skin dry completely before injecting. ^[11][12]
• Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. ^[11][12][13]
• Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. ^[11]
• Inject slowly, at roughly 10 seconds per mL. ^[11]
• Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. ^[6][11][12]

Hygiene and warning signs

• Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. ^[5][9][12]
• Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. ^[5][8][9]
• Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. ^[14][15]
• Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. ^[12]

Where to inject: subcutaneous injection sites.

How Oxytocin works

• Oxytocin is a nine-amino-acid peptide hormone (a nonapeptide) found in the pituitary. The approved injection is made synthetically to avoid contamination with vasopressin. ^[16]
• It binds oxytocin receptors in the muscle of the uterus and raises calcium inside the muscle cells, which drives contractions. The number of receptors rises sharply in pregnancy and peaks in early labour at term, so the response varies a lot from person to person. ^[16]
• Oxytocin differs from vasopressin at only two amino-acid positions. The label says this is thought to be why large doses can raise blood pressure and cause the body to hold on to water. ^[16]
• Its plasma half-life is about 1 to 6 minutes, and it is cleared mainly by the kidneys and liver. Given intravenously, the uterus responds almost at once, and the effect fades within an hour. ^[16]

What the Oxytocin research found

Human evidence: moderate human evidence. Each result says what was studied.

• Human studyA 2019 Cochrane review of 24 trials (23 contributing data from 10,018 women) found that oxytocin given in the third stage of labour after vaginal birth, compared with no uterotonic or placebo, may reduce the risk of losing 500 mL of blood or more by about half (risk ratio 0.51; 6 studies, 4,162 women). It probably also reduces the need for further uterotonic drugs. The evidence was of low to moderate quality. ^[17]
• Human studyIn a 2021 placebo-controlled trial of 290 children and adolescents with autism, 24 weeks of intranasal oxytocin (target 48 IU daily) made no significant difference to social withdrawal scores compared with placebo (change of -3.7 against -3.5). Secondary social and cognitive measures generally did not differ either. ^[18]
• Human studyAn earlier small pilot dose-finding study of 15 young people with autism gave daily intranasal oxytocin for 12 weeks. The highest dose tested (0.4 IU/kg) was well tolerated, and several social and anxiety measures changed over the course of treatment. ^[19]
• Human studyA 2011 systematic review of 38 randomised trials of intranasal oxytocin (1,529 participants, 79% male) found that participants could not tell whether they had received oxytocin or placebo, and reported no detectable subjective changes. ^[20]
• Human studyA 2023 review of oxytocin for obesity concluded it may have a role, but that further clinical trials are needed to establish whether it is safe and effective. ^[21]

Oxytocin side effects and risks

The label covers the injection, given in hospital with monitoring; the intranasal safety data come from supervised, time-limited research use.

• FDA labelReported maternal reactions to the injection include anaphylaxis, irregular heart rhythms, postpartum haemorrhage, pelvic haematoma, subarachnoid haemorrhage, fatal afibrinogenaemia, hypertensive episodes, nausea, vomiting and rupture of the uterus. ^[16]
• FDA labelOxytocin's antidiuretic effect can cause water intoxication, especially when large doses are infused over long periods. Severe cases with convulsions and coma, and maternal deaths, have been reported. ^[16]
• FDA labelToo much oxytocin, or hypersensitivity to it, can cause overly strong or sustained contractions and uterine rupture. Reported effects in the baby include slow heart rate, arrhythmias, low Apgar scores, jaundice, retinal haemorrhage, seizures, permanent brain damage and fetal death. ^[16]
• Human studyAcross 38 randomised trials of short-term intranasal oxytocin at 18 to 40 IU, side effects did not differ from placebo. The review found three case reports of adverse reactions, all linked to misuse or longer-term use. ^[20]
• Human studyIn the 24-week autism trial of daily intranasal oxytocin in 290 children and adolescents, adverse events were similar in frequency and severity to placebo. ^[18]

Other things to know

• The approval belongs to a different product, route, purpose and setting. Citing it for a nasal spray sold for desire is the most common move in how this compound is marketed.
• No randomised trial was located for the sexual-function use it is sold for.
• Published safety data describes supervised, time-limited trial use, which is not evidence about indefinite self-administration from an unverified source.

Reported side effects and what the studies measured: Oxytocin side effects.

Where this vial size comes from

Oxytocin is sold as a 5 mg vial by the pages below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

• Origin CompoundsvendorLists it as: Oxytocin - 5mg; 5mg Vial. Lyophilized Powder · checked 2026-09-28
• Peptide WarehousevendorLists it as: Available In 5MG · checked 2026-09-28

The doses come from the sourced common protocol on the Oxytocin dosing page, and every number on this page is arithmetic on those doses and this vial size.

Other Oxytocin vial sizes

• 5 mg
• 10 mg vial

Questions

How much water do I add to a 5 mg Oxytocin vial?

There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1 mL the vial is 5 mg/mL and 300 mcg is 6 units (0.06 mL) on a U-100 insulin syringe. The units table gives 1, 2, 5 mL.

How many doses are in a 5 mg Oxytocin vial?

100 doses at 50 mcg, 16 doses at 300 mcg, 10 doses at 500 mcg.

How long does a 5 mg Oxytocin vial last?

At 300 mcg a dose and once daily to every other day, about 2.3-5.3 weeks. How long a mixed vial keeps is a separate limit; see storage below.

How many 5 mg vials do I need for a cycle?

1 vial at 50 mcg 3 times a week for 8 weeks; 9 vials at 500 mcg 7 times a week for 12 weeks.

What does 1 unit equal in a 5 mg Oxytocin vial?

50 mcg with 1 mL, 25 mcg with 2 mL, 10 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.