PT-141 + Oxytocin: What It Is, Where to Get It Prescribed, and What It Costs

PT-141 + Oxytocin is not a single molecule. It is two separately studied peptides dissolved together in one sterile multi-dose vial by a compounding pharmacy. That makes it unusual among the blends on this site: both components are the active ingredient of a drug the FDA has approved as a finished product. PT-141 is bremelanotide, sold as Vyleesi for one indication in women. Oxytocin is the active ingredient of Pitocin, used in hospitals during and after labour. Each has its own literature, mechanism and regulatory file. The combination has none of those; it has never been studied as a combination.

"PT-141" was bremelanotide's development code at Palatin Technologies; it emerged from work on Melanotan II, a synthetic alpha-MSH analogue studied for tanning whose subjects reported unexpected effects on arousal. Vyleesi is the brand approved in 2019. Oxytocin was one of the first peptide hormones ever synthesised, and synthetic oxytocin has been an approved hospital drug since 1980.

It is not a PDE5 inhibitor and does not act on blood flow to the genitals; PT-141 acts in the brain. It is not a daily medication: the directions are per occasion, capped by month, and nothing in the literature describes a cumulative benefit from more frequent use. It is not a treatment for a relationship problem, for depression, or for low desire caused by another medication — Vyleesi's label excludes all three from its indication. And it is not hormone replacement; no oxytocin deficiency state for sexual function has been defined.

Bremelanotide is a non-selective melanocortin receptor agonist. Its approved label ranks its potency as MC1R, then MC4R, MC3R, MC5R and MC2R, with MC1R and MC4R the relevant two at therapeutic doses. A 2022 review in CNS Spectrums describes the medial preoptic area of the hypothalamus as the site that matters: animal studies suggest bremelanotide activates presynaptic MC4 receptors there, increasing release of dopamine, the excitatory transmitter in the desire circuit.

Two caveats. The Vyleesi label states plainly that the mechanism by which it improves hypoactive sexual desire disorder is unknown; the dopamine account is the leading explanation, not a settled one. And MC1R, which bremelanotide binds most strongly, is the melanocyte receptor that drives pigmentation — which is why focal darkening of skin is a described side effect rather than a curiosity.

Oxytocin's approved role is peripheral: it contracts the uterus and drives milk let-down. Its research role is central. A 2015 review in the European Journal of Pharmacology summarises the animal literature, describing roles in female appetitive and copulatory behaviour including orgasm, in male erection and ejaculation, and in pair bonding. In humans, plasma oxytocin is reported to rise around orgasm.

The difficulty is getting it to the brain. Oxytocin crosses the blood-brain barrier poorly. A 2016 paper in Biological Psychiatry, "Intranasal Oxytocin: Myths and Delusions," argues that very little of the large intranasal research doses reaches cerebrospinal fluid, while peripheral concentrations rise to supraphysiological levels with likely effects on the gut, heart and reproductive tract. That applies equally to a subcutaneous injection, and it is the reason to treat oxytocin's bonding reputation as a hypothesis when it comes from a vial.

The rationale prescribers give is that PT-141 is described as acting on desire and initiation, and oxytocin on the orgasmic and post-orgasmic phase and the closeness afterwards — the one couples study that reported any oxytocin effect found it there, not on drive or arousal. One injection before intimacy is meant to cover both ends of the sequence.

That is a rationale, not a finding. No study has tested whether oxytocin adds anything to PT-141. The proportions are fixed by the formulation — each 0.10 mL dose of the standard strength delivers 0.2 mg PT-141 and 0.1 mg oxytocin — and cannot be adjusted per component.

This is the strongest human evidence for any product in this category. Two identical phase 3, randomised, double-blind, placebo-controlled trials — Studies 301 and 302, together called RECONNECT, published in Obstetrics & Gynecology in 2019 — enrolled 1,267 premenopausal women with acquired, generalised hypoactive sexual desire disorder and randomised them to bremelanotide 1.75 mg subcutaneously as needed, or placebo, for 24 weeks. Both trials met both co-primary endpoints: desire scores on the Female Sexual Function Index rose 0.30 and 0.42 points more than placebo, and distress scores fell 0.37 and 0.29 points more than placebo. Those are statistically robust and, by the responder definitions set in the earlier phase 2b programme, clinically meaningful; they are also modest in absolute size, and it is worth being clear-eyed about that. Nausea, flushing and headache each occurred in 10% or more of women on bremelanotide.

A 52-week open-label extension followed 684 women who chose to continue: no new safety signals, improvements sustained, nausea still the most common drug-related event at 40%. Most women used it two to three times a month.

The male data are older, smaller, and never produced an approved product. Two 2004 papers in the International Journal of Impotence Research report the developer's early work: intranasal PT-141 produced a statistically significant erectile response, measured by RigiScan, at doses above 7 mg in healthy volunteers without visual stimulation and in men with mild-to-moderate erectile dysfunction; subcutaneous doses above 1 mg did so in healthy men, and 4 mg and 6 mg in men with an inadequate response to sildenafil 100 mg. Those are early-phase pharmacodynamic studies, not outcome trials. The programme did not continue to approval, and Vyleesi's label states it is not indicated in men. Prescribing PT-141 to men is an off-label use of an approved active, resting on those studies plus clinical experience.

The human work is almost entirely intranasal, and small. The study most often cited in favour is a 2014 paper in Hormones and Behavior in which 29 healthy couples took 24 IU of intranasal oxytocin or placebo before sex at home. Oxytocin did not change sexual drive, arousal, erection or lubrication. It was associated with higher reported orgasm intensity and post-sex contentment, more so in men, with effect sizes the authors describe as small to moderate.

The better-controlled results go the other way. A 2015 randomised, double-blind, placebo-controlled crossover trial in Fertility and Sterility gave 30 pre- and postmenopausal women with sexual dysfunction 32 IU of intranasal oxytocin or placebo on demand before intercourse, eight weeks each arm. Sexual function improved substantially in both arms — the Female Sexual Function Index rose 26% on oxytocin and 31% on placebo — with no treatment effect. A 2017 follow-up found the male partners' sexual quality of life improved whichever spray their partner used, again with no difference. In men directly, a 2008 double-blind crossover study in Psychoneuroendocrinology gave ten healthy men 24 IU before laboratory-induced arousal and orgasm: plasma oxytocin rose sharply, but sexual behaviour did not change.

None of these studies used a subcutaneous injection, and none used oxytocin alongside a melanocortin agonist.

• PT-141 has two positive phase 3 randomised controlled trials and a 52-week extension in premenopausal women, the basis of its approval as Vyleesi. It has early-phase studies in men, no outcome trial in men and no approval for men.
• Oxytocin has small intranasal human studies: one couples study reporting effects on orgasm and contentment, and a randomised crossover trial in women with sexual dysfunction reporting no difference from placebo. No human trial of subcutaneous injection for sexual function exists.
• The combination has no trials of any kind, in humans or animals.

The accurate framing is: one component with strong trial evidence in one population, one with mixed and mostly null human evidence, and none for the two together.

• That oxytocin adds anything to PT-141. No study has compared the blend with PT-141 alone.
• That PT-141 improves sexual desire or satisfaction in men over time. The male evidence measures erections in a laboratory.
• That the compounded dose reproduces the trial results. RECONNECT used 1.75 mg per dose; the reviewed compounded directions deliver 0.2 mg PT-141 per injection alongside oxytocin, and your physician sets the dose.
• Long-term safety of oxytocin injection at these doses, because those studies have not been run.

Vyleesi (bremelanotide injection) was approved by the FDA on 21 June 2019 under NDA 210557 for premenopausal women with acquired, generalised hypoactive sexual desire disorder. It is a 1.75 mg/0.3 mL single-dose autoinjector, dosed at least 45 minutes before anticipated sexual activity, no more than once in 24 hours and no more than eight times a month. The application is now held by Cosette Pharmaceuticals, and its prescribing information on DailyMed was last updated in November 2025, so it remains a marketed prescription product as of September 2026.

Pitocin (oxytocin injection, USP) was approved on 19 November 1980 under NDA 018261 and is supplied at 10 USP units/mL for intravenous infusion or intramuscular injection. Its labelled indications are obstetric: induction or improvement of labour where medically indicated, and control of postpartum bleeding. Sexual function appears nowhere on that label, and nor does subcutaneous use.

Section 503A of the Food, Drug and Cosmetic Act allows a state-licensed pharmacy to compound from a bulk substance if it has a USP or NF monograph, or is a component of an FDA-approved drug product, or appears on the FDA's 503A bulks list. Bremelanotide and oxytocin qualify by the second route. Neither has ever been nominated to, or placed in any category of, the FDA's 503A bulk drug substances list, and neither was affected by the 15 April 2026 removal of twelve peptides from Category 2 or discussed at the Pharmacy Compounding Advisory Committee's 23–24 July 2026 meeting. That is checked against the FDA's category list as current at 14 May 2026 and the July meeting page.

A compounded PT-141 + Oxytocin vial is not Vyleesi and not Pitocin. It is a different formulation — two actives together, at a different concentration, in a multi-dose vial — prepared by a licensed pharmacy to an individual prescription. The FDA has not reviewed that formulation, and compounded medications are never FDA approved. Prescribed to men, or to women outside Vyleesi's indication, it is off-label use of an approved active.

Most of what is noticed on a first dose is the side effects, because they arrive before the intended effect. Vyleesi's label reports that nausea, when it occurs, typically starts within an hour and lasts about two, is most common with the first dose and improves with later ones. Some people notice nothing at all. A first dose is often best taken on an occasion where a poor response would not matter.

PT-141 reaches peak plasma levels about an hour after a subcutaneous dose and has a half-life under three hours; the male studies describe onset within roughly 30 minutes. The blood-pressure effect on the label peaks in the same two-to-four-hour window and has usually resolved by 12 hours. The useful window is several hours, not a whole day.

Each dose stands on its own: nobody reports it building up, and there is no withdrawal and no rebound described for either component. The eight-a-month cap is a safety ceiling from the approved label, not a target: more frequent dosing raises the risk of focal hyperpigmentation and lengthens the time each month that blood pressure is raised. Reaching for it more often than directed is a conversation with your physician, not a reason to stretch the vial.

The directions are written in millilitres and insulin-syringe units because that is what you can read off the barrel. 0.10 mL is 10 units on a U-100 syringe; the number is printed on your medication. Because the two components are in fixed proportion, every dose delivers the same split: 0.2 mg PT-141 with 0.1 mg oxytocin from the standard strength, or 0.2 mg PT-141 with 1 mg oxytocin from the higher-oxytocin strength. If your directions and syringe markings appear to disagree, ask before dosing.

Subcutaneous means into the fat layer, not the muscle. Abdomen and thigh are the usual sites — Vyleesi's label found no difference in absorption between them — rotated so the same spot is not used repeatedly.

Fifty doses at 0.10 mL is the arithmetic. How long a vial actually lasts depends on how often it is used: the directions cap use at eight a month, and most women in the Vyleesi programme used two to three. At that rate the beyond-use date on the label, not the dose count, determines when a vial is replaced. One vial per fill, always — not a stockpile. Your physician manages the refill interval.

Refrigerated, and it ships that way in insulated packaging with ice packs. Keep it in the fridge between uses and do not freeze it; the beyond-use date is on the label.

The only difference is oxytocin. PT-141 alone is the component with two positive phase 3 trials behind it; the blend adds a component whose controlled human evidence for sexual function is mostly null. If desire and initiation are the whole problem, PT-141 alone is the more targeted prescription. The blend is for someone whose physician judges the orgasm-and-closeness part of the picture worth addressing in the same injection, accepting that the evidence for that part is thin.

Oxytocin on its own carries none of PT-141's nausea, flushing, blood-pressure or pigmentation profile, and none of its trial evidence either. For someone whose interest is closeness or the post-orgasmic phase, with no complaint about desire, oxytocin alone is the honest fit.

A PDE5 inhibitor works on penile blood flow and has decades of outcome trials; it does nothing for desire. PT-141 works on desire and central arousal and, in the early male studies, produced erections in men who had not responded adequately to sildenafil. They address different failures, and the blend is not a substitute for a vascular drug when the problem is vascular.