PT-141
PT-141 (Bremelanotide)
Also called bremelanotide, Vyleesi, PT141
The libido peptide
PT-141, sold as Vyleesi, is an approved medicine for low sexual desire in premenopausal women. It is unusual among these compounds in acting on the brain rather than on blood flow, which is why it works differently from Viagra. It is an injection taken before sex rather than daily.
An injection taken before sex, approved as Vyleesi for low sexual desire in premenopausal women. Viagra and its relatives work on blood flow; this works on wanting, acting on the part of the brain that sets drives like hunger and arousal. That is why it can help where the plumbing was never the problem.
- Typical dose
- 1.75 mg as needed
- Availability
- Research-only
Tested in several human trials
121 papers · 16 clinical trials
What people use PT-141 for
Reported uses, roughly in order of how often they are the reason someone goes looking. Whether it works for any of them is a separate question, answered under each one.
- Low sexual desire in women
- Its approved use, in premenopausal women with hypoactive sexual desire disorder.
- Erectile difficulty
- Used off-label by men. This is not what it is approved for and the trials behind approval were in women.
Mechanism of Action
How PT-141 works
Viagra and the drugs like it work on plumbing. They improve blood flow, which helps if blood flow is the problem, and does nothing at all if the problem is that you do not want to.
PT-141 works on the wanting.
Where it acts
It reaches receptors in the hypothalamus, a part of the brain involved in setting drives like hunger, temperature and sexual motivation. Rather than opening blood vessels downstream, it acts upstream, on the signal that starts the whole sequence.
That is why it is the approved treatment for low sexual desire in premenopausal women, a condition where the plumbing was never the issue. It is also why it is taken before sex rather than daily, and why the effect builds over a couple of hours instead of arriving on a schedule.
What that mechanism costs
The receptors it acts on are not only in the brain. The same family governs skin pigment, which is why repeated use can darken patches of skin.
It also raises blood pressure briefly while slowing heart rate. That effect is the reason the nasal version was abandoned: getting enough through the nose meant doses where the cardiovascular effect stopped being manageable. The injection at its approved dose produces a much smaller rise, but it is still why this is not recommended if your blood pressure is uncontrolled.
How well does it work
It is approved, which puts it ahead of most things on this site. It is also genuinely debated: a 2024 analysis went back to the approval trials and argued the questionnaires used to measure success were poorly validated and the actual improvement modest.
Both things are true. Approval means it cleared a bar, not that the effect is large.
PT-141 dosage calculator
Opens at 1.75 mg, from the doses reported for PT-141. Change any box to match your own vial. It works out where to pull the plunger to.
How much is in the vial?
Printed on the label, in milligrams
How much water did you add?
Bacteriostatic water, in millilitres
What dose are you taking?
The dose you already intend to use
Which syringe?
Barrel size, printed on the wrapper
Draw to
35 units
on a 0.5 mL insulin syringe (0.35 mL)
- Strength once mixed
- 5 mg/mL
- Doses in the vial
- 5
10 mg in 2 mL makes 5 mg/mL. A 1.75 mg dose is 0.35 mL of that, which is 35 units.
Want a rounder number? Adding 0.57 mL instead would put this dose at exactly 10 units, which is easier to draw accurately.
This is arithmetic, not advice. It converts a dose you already have into a mark on a syringe. It does not tell you what dose to take, and PT-141 is not prescribed by us. Dosing belongs with a qualified clinician.
PT-141 side effects: what people reported
This one has a side effect people genuinely need warning about, because it is common enough to ruin the evening it was meant to improve: nausea. Roughly four in ten people in trials got it.
What most people notice
- Nausea, and enough of it that taking a first dose on an important night is a bad plan
- Flushing
- Headache
- Injection-site reactions
- A stuffy nose
Worth keeping an eye on
- A short-lived rise in blood pressure with a small drop in heart rate, peaking a few hours after a dose
- Darkening of skin, freckles, moles or gums with frequent repeated use, since it acts on the same receptors that control pigment
- It is meant for occasional use rather than daily, and people who ignore that are the ones who report the pigment changes
Reasons to check first
- Uncontrolled high blood pressure or known cardiovascular disease, because of the transient pressure rise
Dose matters. Nausea tracks the dose closely. Most people who tolerate it well got there by using less, not by pushing through.
Source: RECONNECT trials for bremelanotide, plus prescribing experience. This is a summary of published findings, not a complete safety profile and not medical advice. PT-141 should only be considered with a qualified clinician who knows your history.
Your Genetics & PT-141
The genes involved in how PT-141 works
PT-141 works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
MC4R · ••
MC4R is PT-141's primary target. Loss-of-function variants here can change melanocortin signaling; wild-type / non-risk genotypes carry no loss-of-function responder or non-responder signal — meaning no genetic reason to expect a blunted response.
MC4R · ••
A second common MC4R variant. Non-risk genotypes again give no loss-of-function signal, so the receptor PT-141 acts on is intact.
COMT · ••
The Met/Met (slow-COMT) genotype clears catecholamines slowly, which can modestly amplify or prolong PT-141's central adrenergic side effects (flushing, nausea, blood-pressure bump) — a tolerability watch-item rather than an efficacy one.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which variants do you carry?
Upload your DNA data, or get tested through our partner, to find out.
Commonly combined with
What PT-141 is most often paired with, and why:
Oxytocin
Intimacy StackModerate EvidenceOxytocin (The Bonding Hormone)
The body's bonding and trust hormone — FDA-approved as Pitocin for labor, and used off-label intranasally for social connection, anxiety and intimacy. Oxytocin acts in the brain to lower social-threat responses and deepen feelings of trust and closeness. Crucially, response is strongly gene-stratified: your OXTR receptor genotype sets how much you actually feel it.
4
Gene variants
40+
Studies
Sourcing & access
Where to buy PT-141
PT-141 is available through licensed telehealth and retail providers. We rank them by price, reviews and a credibility score — so you can find the cheapest source that's actually legitimate.
- Buy only from licensed providers that publish recent third-party purity tests (COAs).
- Compare the total cost — consultation, the compound, and shipping — not just the sticker price.
- Confirm the provider ships to your country and requires a genuine medical intake.
Before you buy: see whether your DNA actually responds to PT-141, and at what dose. Analyze my DNA — $99 →
Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you). Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Worth knowing before you consider PT-141
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- It raises blood pressure, which is why the dose is what it is
- A transient rise in blood pressure with a fall in heart rate is the known effect. It is the reason the nasal version was abandoned: reaching useful levels through the nose needed doses where the cardiovascular effect was not manageable. It is not recommended in uncontrolled high blood pressure or known cardiovascular disease.
- Nausea is common and darkening of the skin can happen
- Nausea is the most frequent complaint in the trials. Because it acts on melanocortin receptors, the family involved in pigmentation, focal darkening of skin can occur, more often with repeated dosing.
- The effect size is genuinely debated
- Approval is not the same as a large benefit. The published critique below argues the improvement on the trial questionnaires was small and the questionnaires themselves poorly validated for this condition. Worth reading before deciding what to expect.
The evidence behind PT-141
This is one of the few approved medicines in the catalogue, so the evidence is real. What makes it interesting is that the argument did not end at approval: a 2024 analysis in the Journal of Sex Research went back to the trials and argued the questionnaires used to measure success have questionable validity, and that the actual effect was small. Both things are true at once, and a page that gives you only the approval is telling you half of it.
The literature, counted
Counted in PubMed on 3 August 2026 for bremelanotide OR PT-141. Every figure links to the search that produced it, so you can re-run it. “Tagged human” is not the same as a human trial: that tag also covers work on human cells and reviews discussing people, which is why the trial count is given separately.
Studied in people
1 of 1The only kind that directly answers whether it works in humans.Reviews
2 of 3Papers that gather other studies rather than run new ones.Journal of Sex Research · 2024
ReviewSmall Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder
Spielmans GI, Ellefson E
Re-examined the RECONNECT trials and concluded the questionnaires used to judge success have questionable validity for this condition, and that the categorical response outcomes had no validity evidence at all. The honest counterweight to the approval, and it is almost never cited alongside it.
Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder — source for PT-141 (opens in a new tab)Read the reviewCNS Spectrums · 2022
ReviewThe neurobiology of bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women
Mayer D, Lynch SE
Explains why this works differently from the erectile-dysfunction drugs. Those act on blood flow; this acts on melanocortin receptors in the brain, upstream of arousal rather than downstream of it.
The neurobiology of bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women — source for PT-141 (opens in a new tab)Read the review
Every source behind this page52 more
- An evaluation of bremelanotide injection for the treatment of hypoactive sexual desire disorderSimon JA, Kingsberg SA · Expert Opinion on Pharmacotherapy · 2023Review
- Bremelanotide: New Drug Approved for Treating Hypoactive Sexual Desire DisorderDhillon S, Keam SJ · Annals of Pharmacotherapy · 2020Official
Everything we cite for PT-141, including animal work and early research. Each link goes to the source itself, so you can judge it rather than take our word for it.
Last updated · literature counts verified against PubMed on
Frequently Asked Questions
What is PT-141 used for?
PT-141 (bremelanotide) is used to increase sexual desire. It's FDA-approved as Vyleesi for HSDD in premenopausal women and used off-label for low libido and erectile difficulty in men. It acts on the brain's melanocortin system rather than on blood flow.
How is PT-141 different from Viagra?
Viagra and Cialis (PDE5 inhibitors) improve blood flow to enable an erection. PT-141 works upstream — in the brain — to increase desire itself. That's why it can help in cases where blood-flow drugs don't, and why it works in women as well as men.
Does genetics affect PT-141 response?
Your MC4R genotype is the key — PT-141 targets the MC4R receptor, so loss-of-function variants are what would matter. COMT (Met/Met) genetics don't change whether it works, but can make its central side-effects more pronounced. A genetic report flags both.
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Your next move
Two ways forward with PT-141.
Not sure it's for you?
How does PT-141 relate to your genes?
Your report scores PT-141 against your receptor, pharmacogene and pathway variants and shows the genetic markers relevant to it, with commonly cited dosing information to review with a clinician.
Analyze my DNA — $99Already decided?
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