Intimacy · Reference
Oxytocin Dosage: How Pepti Prescribes Oxytocin Injections
This page explains the oxytocin dosage Pepti prescribes, what the units on the syringe mean, a dosage chart for the oxytocin vial, why the hospital product's units and the nasal-spray study doses do not translate to the compounded injection, how oxytocin compares with the PT-141 + Oxytocin vial, what can change your directions, and the side effects to know about. It covers how Pepti prescribes oxytocin, not online protocols. Nothing here is a reason to change your own dose.
Treatments mentioned
At Pepti, oxytocin is typically prescribed as 0.18 mL, which is 18 units on a U-100 insulin syringe, injected under the skin once daily. The 5 mL vial holds 10 mg of oxytocin at 2 mg/mL, so each 0.18 mL dose delivers 0.36 mg, and the vial holds about 27 full doses, roughly four weeks of daily use. Your physician sets your directions after reviewing your intake, and your exact dose and units are printed on the vial.
This page explains the oxytocin dosage Pepti prescribes, what the units on the syringe mean, a dosage chart for the oxytocin vial, why the hospital product's units and the nasal-spray study doses do not translate to the compounded injection, how oxytocin compares with the PT-141 + Oxytocin vial, what can change your directions, and the side effects to know about. It covers how Pepti prescribes oxytocin, not online protocols. Nothing here is a reason to change your own dose.
Oxytocin Dosage
The short answer
| Product | Vial | Typical directions | Per dose | Doses per vial | Price |
|---|---|---|---|---|---|
| Oxytocin | 5 mL, oxytocin 2 mg/mL (10 mg per vial) | Inject 0.18 mL (18 units) subcutaneously once daily | 0.36 mg | About 27 | $239/mo |
Every price is all-in, covering medication, physician review, refill management and shipping, with no separate membership fee. Pepti is cash-pay and does not bill insurance. Your own directions are the ones printed on your vial.
You may see oxytocin described elsewhere as an injection used only on the day, timed before intimacy. Pepti's current typical printed directions are a once-daily dose. Whichever directions are printed on your vial are the ones that apply, and if anything about them is unclear, message your care team before dosing.
Oxytocin Dosage
Oxytocin dosage in units, mL and mg
Pepti's directions are written in millilitres and units, because prescriptions are written in millilitres and insulin syringes are marked in units. On a U-100 insulin syringe, 1 unit is 0.01 mL, so 100 units is 1 mL and 18 units is 0.18 mL. A unit on the syringe is a volume mark on the barrel, not a measure of how strong the medication is.
The milligrams per dose come from the vial's concentration multiplied by the volume:
| Step | Value |
|---|---|
| Concentration | 2 mg/mL |
| Typical dose volume | 0.18 mL (18 units) |
| Oxytocin per dose | 0.18 mL x 2 mg/mL = 0.36 mg |
| Doses per week | 7 (once daily) |
| Oxytocin per week | 7 x 0.36 mg = 2.52 mg |
| Oxytocin per vial | 10 mg |
That arithmetic is a way to read a label, not a way to set a dose. A vial labelled 10 mg is not a 10 mg dose. If your label and your syringe seem to disagree, do not dose; message your care team. How long does a peptide vial last explains every number on a vial label.
Syringe units are not USP units
This is the most common source of confusion with oxytocin. The FDA-approved hospital oxytocin injection is labelled in USP units, a measure of biological activity, at 10 USP units per mL for intravenous or intramuscular use in labour. The compounded vial is labelled in milligrams per millilitre. The "18 units" in Pepti's directions are syringe units, that is 0.18 mL of liquid, and have nothing to do with USP units. The two systems are not interchangeable, and a figure from one cannot be read on the other.
The same applies to research: the human studies of oxytocin and intimacy used a nasal spray at doses such as 24 or 32 IU. A nasal dose in international units cannot be converted into a subcutaneous dose in milligrams, and the studies did not test injections.
Oxytocin Dosage
Oxytocin dosage chart: units to mL to mg
The chart below is the conversion for the 2 mg/mL oxytocin vial, drawn with a U-100 insulin syringe. It is math only. It is not a menu of doses, and the only line that applies to you is the one that matches the number printed on your vial.
| Syringe mark (U-100) | Volume | Oxytocin |
|---|---|---|
| 5 units | 0.05 mL | 0.1 mg |
| 10 units | 0.1 mL | 0.2 mg |
| 15 units | 0.15 mL | 0.3 mg |
| 18 units (Pepti's typical directions) | 0.18 mL | 0.36 mg |
| 20 units | 0.2 mL | 0.4 mg |
| 25 units | 0.25 mL | 0.5 mg |
| 50 units | 0.5 mL | 1 mg |
| 100 units | 1 mL | 2 mg |
The rule behind every row: units divided by 100 gives millilitres; multiply millilitres by 2 for milligrams of oxytocin. That multiplier only holds for this vial. The PT-141 + Oxytocin vial carries oxytocin at 1 mg/mL, half this strength, so the same units deliver half as much oxytocin, which is the main reason not to dose from a chart, including this one.
Reading 18 units on the syringe
Eighteen units sits between two of the larger marks on most syringes. On a syringe marked every unit, it is eight small marks past 10; on one marked every two units, it is four marks past 10. Draw slowly, check against the light, and if you are not sure your syringe has fine enough markings, ask your care team before dosing.
Oxytocin Dosage
Oxytocin compared with PT-141 + Oxytocin
Oxytocin is also one of the two actives in the PT-141 + Oxytocin vial. The two products are dosed very differently:
| Oxytocin | PT-141 + Oxytocin | |
|---|---|---|
| What is in the vial | 5 mL: 10 mg oxytocin (2 mg/mL) | 5 mL: 10 mg PT-141 (2 mg/mL) and 5 mg oxytocin (1 mg/mL) |
| Typical directions | 0.18 mL (18 units) once daily | 0.10 mL (10 units) 2 to 4 hours before sexual activity, no more than 8 doses a month |
| Oxytocin per dose | 0.36 mg | 0.1 mg |
| Other active per dose | None | 0.2 mg PT-141 |
| How long a vial lasts | About four weeks | Set by use and the beyond-use date; capped at 8 doses a month |
| Price | $239/mo | $259/mo |
The combination is a per-occasion product with a monthly cap that comes from the PT-141 component's approved label; oxytocin on its own carries none of PT-141's nausea, flushing, blood pressure or pigmentation profile. Taking both products together would add oxytocin from two vials and is not something to do without your physician's review. How the two molecules differ is in PT-141 vs oxytocin, and PT-141 dosing is in PT-141 dosage.
Oxytocin Dosage
When and how oxytocin is taken
Once daily, under the skin
Pepti's typical oxytocin directions say once daily. Subcutaneous means into the fat layer, not the muscle. Abdomen and thigh are the usual sites, rotated so the same spot is not used repeatedly. Technique is covered in how to inject peptides safely.
| Directions say | What it means in practice |
|---|---|
| 0.18 mL (18 units) | Draw to the 18 mark on a U-100 insulin syringe |
| Subcutaneously | Into the fat layer, abdomen or thigh, rotating sites |
| Once daily | One dose a day, seven days a week |
| About 27 doses per vial | Roughly four weeks, then the next refill |
Why the timing of each dose is short-lived
Oxytocin has a plasma half-life of a few minutes. Levels rise within minutes of a subcutaneous injection and clear quickly, and nothing accumulates from one day to the next. If your directions name a time of day, follow them; if they do not, ask your care team whether timing matters for you.
Oxytocin Dosage
How long an oxytocin vial lasts, storage and refills
| Step | Value |
|---|---|
| Dose | 18 units, 0.18 mL |
| Doses per week | 7 |
| Doses per vial | 5 mL divided by 0.18 mL = about 27.8, so 27 full doses |
| Time per vial | About four weeks |
| Refills | Every 28 days, one vial per fill |
Vials are multi-dose solutions shipped ready to use, refrigerated with ice packs, with sterile syringes and alcohol prep pads. Nothing is mixed at home. Heat degrades oxytocin, so the vial goes back in the fridge after each draw; beyond-use dating runs from first puncture and is on the label. Cloudiness, particles or a colour change is a reason to message rather than inject. Which peptides need refrigeration and how to store peptides cover storage.
If a vial runs short before the refill, message your care team rather than adjusting anything yourself. If you miss a dose, follow your directions and do not take two doses to make up for one.
Oxytocin Dosage
Why the research cannot give you an oxytocin dose
Unusually for a compounded peptide, oxytocin has many randomised human trials, but none of them tested the injection that is prescribed. The 2014 couples study in Hormones and Behavior, the 2015 trial in women with sexual dysfunction in Fertility and Sterility, the 2009 social anxiety trial and the 2021 SOARS-B autism trial in the New England Journal of Medicine all used a nasal spray. The approved hospital product is dosed by infusion in labour, a completely different use. There are no randomised trials of subcutaneous oxytocin for intimacy, mood or social function, so there is no trial-derived dose for it. The directions on your vial are a prescribing standard set by your physician after reviewing your intake. The evidence is set out in oxytocin benefits and what is oxytocin.
Oxytocin Dosage
What changes the directions
Your physician sets your directions after reviewing your intake. Things that can lead to different directions, or a different product, include:
| What can change | How it shows up |
|---|---|
| Whether oxytocin is the right product | Low desire or arousal may point to PT-141; a hormonal picture to kisspeptin; both desire and connection to PT-141 + Oxytocin |
| Pregnancy, trying to conceive, or breastfeeding | Oxytocin contracts the uterus and is not used in pregnancy outside a hospital |
| A cardiac or fluid-balance condition | The approved label warns of water retention and low blood pressure at large intravenous doses; disclose it at intake |
| Your other medications | There is no established interaction list, so every medication goes on the intake |
| How you respond | Reactions you report go to your physician, who may revise your directions |
When directions change, the new numbers are printed on the new label. Never carry a number over from a previous fill. Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account.
Oxytocin Dosage
Side effects, in summary
| What is reported | What it means | What to do |
|---|---|---|
| Injection-site redness, mild soreness, occasional bruising | What prescribers most often hear about | Rotate sites |
| Brief flushing or headache after a dose | Occasional | Report it if it persists |
| Thirst, increased urination, constipation | The most reported effects in the paediatric nasal-spray crossover trial | Report it if it persists |
| Any chance of pregnancy | Oxytocin contracts uterine smooth muscle | Tell your physician the same day |
| Facial or throat swelling, widespread rash, breathing difficulty | Rare | Call 911 first, then tell your physician |
The full list is in oxytocin side effects. Oxytocin is not named on the 2026 WADA Prohibited List; tested athletes should still check their sport's current rules and tell their physician.
Oxytocin is an FDA-approved active ingredient for obstetric use, but the compounded vial is a different concentration, route and purpose, and compounded medications are not FDA approved. Intimacy is not an approved use of any oxytocin product.
Oxytocin Dosage
Where to get oxytocin prescribed
Oxytocin cannot be bought legitimately without a prescription. Sites selling it "for research use only" are not accountable for what is in the vial: identity, purity, sterility and concentration are untested, so the per-dose figures above would not hold. The prescription route:
- Complete a free online intake covering your history, medications, pregnancy status and what you want help with.
- A physician licensed in your state reviews it, usually within 24 hours.
- If it is appropriate, a PCAB-accredited, FDA-registered US 503A compounding pharmacy prepares it to that prescription. Lot test results are published at /quality/lab-results.
- It ships refrigerated with your directions printed on the vial.
- Your physician stays reachable for questions and dose changes.
The full product reference is what is oxytocin. Related: peptides for libido and kisspeptin vs oxytocin.
References
What this is based on.
References
- Behnia B, Heinrichs M, Bergmann W et al.. Differential effects of intranasal oxytocin on sexual experiences and partner interactions in couples · Horm Behav (2014) · PMID 24503174
- IsHak WW, Berman DS, Peters A. Male anorgasmia treated with oxytocin · J Sex Med (2008) · PMID 18086171
- Burri A, Heinrichs M, Schedlowski M, Kruger TH. The acute effects of intranasal oxytocin administration on endocrine and sexual function in males · Psychoneuroendocrinology (2008) · PMID 18375074
- Muin DA, Wolzt M, Marculescu R et al.. Effect of long-term intranasal oxytocin on sexual dysfunction in premenopausal and postmenopausal women: a randomized trial · Fertil Steril (2015) · PMID 26151620
- Carmichael MS, Humbert R, Dixen J et al.. Plasma oxytocin increases in the human sexual response · J Clin Endocrinol Metab (1987) · PMID 3782434
- Kosfeld M, Heinrichs M, Zak PJ, Fischbacher U, Fehr E. Oxytocin increases trust in humans · Nature (2005) · PMID 15931222
- Guastella AJ, Howard AL, Dadds MR, Mitchell P, Carson DS. A randomized controlled trial of intranasal oxytocin as an adjunct to exposure therapy for social anxiety disorder · Psychoneuroendocrinology (2009) · PMID 19246160
- Sikich L, Kolevzon A, King BH et al.. Intranasal Oxytocin in Children and Adolescents with Autism Spectrum Disorder · N Engl J Med (2021) · PMID 34644471
- Yatawara CJ, Einfeld SL, Hickie IB, Davenport TA, Guastella AJ. The effect of oxytocin nasal spray on social interaction deficits observed in young children with autism: a randomized clinical crossover trial · Mol Psychiatry (2016) · PMID 26503762
- Ooi YP, Weng SJ, Kossowsky J, Gerger H, Sung M. Oxytocin and Autism Spectrum Disorders: A Systematic Review and Meta-Analysis of Randomized Controlled Trials · Pharmacopsychiatry (2017) · PMID 27574858
- Leng G, Ludwig M. Intranasal Oxytocin: Myths and Delusions · Biol Psychiatry (2016) · PMID 26049207
- Walum H, Waldman ID, Young LJ. Statistical and Methodological Considerations for the Interpretation of Intranasal Oxytocin Studies · Biol Psychiatry (2016) · PMID 26210057
Citations are provided for educational purposes. They do not constitute medical advice. Always discuss any peptide protocol with your prescribing physician.
Common questions
Oxytocin Dosage, answered.
At Pepti, the typical printed direction is 0.18 mL, which is 18 units on a U-100 insulin syringe, injected subcutaneously once daily. That is 0.36 mg from the 2 mg/mL vial. Your physician sets your directions after reviewing your intake, and your exact dose is printed on the vial.
The number printed on your vial. Pepti's typical directions are 18 units, which is 0.18 mL on a U-100 insulin syringe, where 1 unit is 0.01 mL.
At 0.18 mL from the 2 mg/mL vial, 0.36 mg. That is arithmetic on the concentration, not a dose recommendation.
No. The hospital product is labelled in USP units of biological activity. Syringe units are volume: 18 units is 0.18 mL. The two cannot be converted into each other.
A 5 mL vial at 0.18 mL a day is about 27 full doses, roughly four weeks. Refills run every 28 days, one vial per fill.
The chart above converts units to millilitres to milligrams for the 2 mg/mL oxytocin vial. It is a conversion, not a list of doses to choose from.
Follow the directions printed on your vial. If you want to discuss a different pattern, message your care team; your physician reviews it and any change is printed on the next label.
No. The combination vial is 1 mg/mL oxytocin, and its typical 0.10 mL dose before sexual activity delivers 0.1 mg oxytocin with 0.2 mg PT-141, capped at 8 doses a month.
No. The intimacy studies used intranasal doses in international units, and no study has tested the subcutaneous injection, so those doses cannot be transferred.
No. Take the dose printed on your vial. Noticing nothing is common; tell your care team rather than changing anything yourself.
No. Pepti vials are multi-dose solutions shipped ready to use, with sterile syringes and alcohol prep pads.
Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account. The free assessment goes to a physician licensed in your state. A consultation does not guarantee a prescription.
Next step
See what a physician recommends for you.
A licensed physician in your state reviews your intake and decides what is appropriate. A consultation does not guarantee a prescription.