PT-141 Reconstitution Calculator
PT-141 has an approved dose, and it is narrower than most people expect. As bremelanotide, sold as Vyleesi, it is FDA-approved and prescription-only for premenopausal women with acquired, generalised hypoactive sexual desire disorder. The label's limitations of use are explicit: it is not indicated for that disorder in postmenopausal women or in men, and it is not indicated to enhance sexual performance. The male erectile-dysfunction doses, which are what most people are looking for when they search this compound, come from phase 1 and phase 2 trials that established an acute erectile response and never progressed to approval, and they sit several times above the approved figure. Both sets appear in the table below, labelled by the population they were given to. Approved product is a ready-to-use solution in a single-dose prefilled autoinjector, so the mixing calculator above applies only to research-grade powder sold under this name, which is a different presentation entirely.
Curated by Dosavy from published literature and regulator labels. Published 11 September 2026, last reviewed 11 September 2026. No clinician reviews this page.
Enter a target dose above to see the draw.
What the evidence says
| Experience | Route | Range | Frequency |
|---|---|---|---|
| Beginner | Subcutaneous | 1.75 mg[1]Population: premenopausal women with acquired, generalised HSDD. Label regimen, quoted: 'The recommended dosage of VYLEESI is 1.75 mg administered subcutaneously in the abdomen or thigh, as needed, at least 45 minutes before anticipated sexual activity.' The label adds that 'the duration of efficacy after each dose is unknown and the optimal window for VYLEESI administration has not been fully characterized', that patients should not take more than one dose within 24 hours, that more than 8 doses per month is not recommended, and that treatment should be discontinued after 8 weeks without symptom improvement. This is the maximum approved dose, not a starting dose to build from. | As needed, at least 45 minutes before anticipated sexual activity; maximum one dose per 24 hours and no more than 8 doses per month |
| Advanced | Subcutaneous | 4–6 mg[2]Population: men with erectile dysfunction reporting an inadequate response to sildenafil 100 mg. In a phase 1/2 crossover, 4 mg and 6 mg subcutaneously each produced a statistically significant erectile response in the presence of visual sexual stimulation; a preceding dose-ranging arm in healthy men covered 0.3 to 10 mg and found significant erectile responses above 1.0 mg. These doses are 2.3 to 3.4 times the maximum approved Vyleesi dose. The label's own pharmacokinetics section notes that exposure rises less than proportionally over 0.3 to 10 mg and plateaus around 7.5 mg, so the extra milligrams buy less than they appear to, while the blood-pressure, nausea and hyperpigmentation warnings were characterised at 1.75 mg and have no established ceiling above it. Bremelanotide was never approved for men or for erectile dysfunction. | Single dose before sexual stimulation |
| Beginner | Intranasal | 10 mg[3][4]Population: men with erectile dysfunction who did not respond to sildenafil. 342 men were randomised to 10 mg bremelanotide as an intranasal spray or placebo, taken 45 minutes to 2 hours before sexual stimulation, with patients asked to use at least 16 doses; 33.5% had a positive clinical result versus 8.5% on placebo, and drug-related adverse effects were significantly more frequent on bremelanotide. An earlier phase 1 study put the threshold for a significant erectile response above 7 mg intranasally, with onset around 30 minutes and no maximum tolerated dose identified. The intranasal formulation was never approved and is not marketed; blood-pressure effects are a known class problem for melanocortin-4 agonists, and the doses here are several times the approved subcutaneous dose. | Single dose, 45 minutes to 2 hours before sexual stimulation |
- BeginnerSubcutaneous
1.75 mg[1]
As needed, at least 45 minutes before anticipated sexual activity; maximum one dose per 24 hours and no more than 8 doses per month
Population: premenopausal women with acquired, generalised HSDD. Label regimen, quoted: 'The recommended dosage of VYLEESI is 1.75 mg administered subcutaneously in the abdomen or thigh, as needed, at least 45 minutes before anticipated sexual activity.' The label adds that 'the duration of efficacy after each dose is unknown and the optimal window for VYLEESI administration has not been fully characterized', that patients should not take more than one dose within 24 hours, that more than 8 doses per month is not recommended, and that treatment should be discontinued after 8 weeks without symptom improvement. This is the maximum approved dose, not a starting dose to build from.
- AdvancedSubcutaneous
4–6 mg[2]
Single dose before sexual stimulation
Population: men with erectile dysfunction reporting an inadequate response to sildenafil 100 mg. In a phase 1/2 crossover, 4 mg and 6 mg subcutaneously each produced a statistically significant erectile response in the presence of visual sexual stimulation; a preceding dose-ranging arm in healthy men covered 0.3 to 10 mg and found significant erectile responses above 1.0 mg. These doses are 2.3 to 3.4 times the maximum approved Vyleesi dose. The label's own pharmacokinetics section notes that exposure rises less than proportionally over 0.3 to 10 mg and plateaus around 7.5 mg, so the extra milligrams buy less than they appear to, while the blood-pressure, nausea and hyperpigmentation warnings were characterised at 1.75 mg and have no established ceiling above it. Bremelanotide was never approved for men or for erectile dysfunction.
- BeginnerIntranasal
Single dose, 45 minutes to 2 hours before sexual stimulation
Population: men with erectile dysfunction who did not respond to sildenafil. 342 men were randomised to 10 mg bremelanotide as an intranasal spray or placebo, taken 45 minutes to 2 hours before sexual stimulation, with patients asked to use at least 16 doses; 33.5% had a positive clinical result versus 8.5% on placebo, and drug-related adverse effects were significantly more frequent on bremelanotide. An earlier phase 1 study put the threshold for a significant erectile response above 7 mg intranasally, with onset around 30 minutes and no maximum tolerated dose identified. The intranasal formulation was never approved and is not marketed; blood-pressure effects are a known class problem for melanocortin-4 agonists, and the doses here are several times the approved subcutaneous dose.
Published ranges, reported as the literature states them and numbered to the sources at the foot of this page. Not a recommendation.
PT-141 has both an approved label and a substantial off-label human literature, and they disagree about dose by a factor of three or more. The approved dose is 1.75 mg subcutaneously as needed, in premenopausal women with HSDD. The male erectile-dysfunction trials (which are the reason most people buy this compound) used 4 to 6 mg subcutaneously or roughly 7 to 10 mg intranasally, established an acute erectile response, and never progressed to approval. Those doses are recorded below because they are real published human doses, not because they are validated: the label's blood-pressure and hyperpigmentation warnings were written for 1.75 mg, and no chronic safety data exists at the higher figures.
PT-141 at a glance
- Category
- Other
- Half-life
- 1.9–4 h
- Routes
- Subcutaneous, Intranasal
- Regulatory status
- Approved
- Also sold as
- Bremelanotide, Vyleesi, PT 141
Mechanism
Bremelanotide is a cyclic seven-amino-acid melanocortin receptor agonist that nonselectively activates several receptor subtypes, in this order of potency: MC1R, MC4R, MC3R, MC5R, MC2R. At therapeutic doses, binding at MC1R and MC4R is the relevant activity. MC4R-expressing neurons are distributed widely through the central nervous system, and the drug's effect on sexual desire is presumed to be central. The FDA label states outright that the mechanism by which it improves HSDD is unknown. MC1R sits on melanocytes, and binding there drives melanin expression, which is why hyperpigmentation is a dose-related adverse effect rather than a curiosity.
Reconstitution
Vyleesi is supplied as 1.75 mg bremelanotide in 0.3 mL solution in a single-dose prefilled autoinjector, a ready-to-use solution requiring no reconstitution. Research-grade 'PT-141' sold as a lyophilised powder is a different presentation with no approved label, no verified potency, and no autoinjector-metered dose; the label's 1.75 mg figure only means 1.75 mg if the vial actually contains what it says.
Storage
Store at or below 25°C (77°F). Do not freeze. Protect from light.
Frequency in practice
As needed before anticipated sexual activity, at least 45 minutes ahead. No more than one dose in 24 hours; more than 8 doses per month is not recommended.
Regulatory
Vyleesi (bremelanotide) is FDA-approved and prescription-only for the treatment of premenopausal women with acquired, generalised hypoactive sexual desire disorder. The label's Limitations of Use are explicit: it is NOT indicated for HSDD in postmenopausal women or in men, and it is NOT indicated to enhance sexual performance. Use in men, use for erectile dysfunction, and use at doses above 1.75 mg are all outside the approval, and the earlier intranasal formulation was never approved for anything.
What to know before anything else
Contraindicated in patients with uncontrolled hypertension or known cardiovascular disease.
Transient increase in blood pressure and reduction in heart rate after every dose: maximal increases of 6 mmHg systolic and 3 mmHg diastolic peaking 2 to 4 hours post-dose, with heart rate falling up to 5 beats per minute; values usually return to baseline within 12 hours. Not recommended in patients at high risk for cardiovascular disease.
Nausea was reported by 40% of patients receiving up to 8 doses per month, required anti-emetic therapy in 13%, and led to discontinuation in 8%.
Focal hyperpigmentation was reported by 1% of patients receiving up to 8 doses per month, including on the face, gingiva and breasts. Risk is higher with darker skin and with daily dosing, and resolution was not confirmed in some patients.
Do not administer more than one dose within 24 hours; more than 8 doses per month is not recommended, because more frequent dosing increases the risk of hyperpigmentation and lengthens the time per month spent with elevated blood pressure.
Avoid with orally administered naltrexone-containing products intended to treat alcohol or opioid addiction. Bremelanotide may significantly decrease naltrexone exposure, and the consequence of naltrexone treatment failure is severe.
Bremelanotide slows gastric emptying and can reduce the rate and extent of absorption of concomitant oral medications, including drugs that depend on threshold concentrations such as antibiotics.
Discontinue if pregnancy is suspected and use effective contraception during treatment; animal reproduction studies showed fetal harm and the lowest dose associated with it has not been identified.
The label directs discontinuation after 8 weeks if the patient reports no improvement in symptoms. Efficacy in the phase 3 programme was statistically significant but small, and that effect size has been publicly contested in the literature.
PT-141 questions
Is there an established dose for PT-141?
There is one approved dose, for one population, and a separate off-label literature that disagrees with it by a factor of three or more. The approved figure is quoted from the 2025 FDA prescribing information for Vyleesi and applies to premenopausal women with hypoactive sexual desire disorder. The male erectile-dysfunction figures come from three trials: a 2004 phase 1/2 crossover in healthy men and in men responding inadequately to sildenafil, a 2004 phase 1 randomised study of the intranasal formulation, and a 2008 double-blind, placebo-controlled trial of that formulation in 342 men. They are recorded below because they are real published human doses, not because anyone validated them. Even for the approved indication, the phase 3 effect was statistically significant but small, and its size has been publicly contested.
How does PT-141 work, and why does it darken skin?
Bremelanotide is a cyclic seven-amino-acid melanocortin receptor agonist that activates several receptor subtypes without selecting between them, most potently MC1R, then MC4R, MC3R, MC5R and MC2R. At therapeutic doses the relevant activity is at MC1R and MC4R. MC4R-expressing neurons are distributed widely through the central nervous system and the effect on sexual desire is presumed to be central, though the FDA label states outright that the mechanism by which it improves the approved condition is unknown. MC1R sits on melanocytes, and binding there drives melanin expression. That is why focal hyperpigmentation is a dose-related adverse effect rather than a coincidence: it is the same receptor binding, in a different tissue.
What does PT-141 do to blood pressure?
Every dose produces a transient rise in blood pressure and a fall in heart rate. The label records maximal increases of 6 mmHg systolic and 3 mmHg diastolic, peaking 2 to 4 hours after the dose, with heart rate falling by up to 5 beats per minute; values usually return to baseline within 12 hours. It is contraindicated in anyone with uncontrolled hypertension or known cardiovascular disease, and not recommended in anyone at high cardiovascular risk. Those figures were characterised at the approved dose and have no established ceiling above it, while the label's pharmacokinetics section notes that exposure rises less than proportionally across the studied range and then plateaus. Additional milligrams buy less than they appear to.
How often can PT-141 be taken?
The label directs no more than one dose in 24 hours and says more than 8 doses per month is not recommended: more frequent dosing raises the risk of hyperpigmentation and lengthens the time spent each month with elevated blood pressure. It is taken as needed, at least 45 minutes before sexual activity, and the label concedes that the duration of efficacy after a dose is unknown. It directs stopping after 8 weeks without improvement.
What are the common side effects of PT-141?
Nausea is the dominant one. Among patients receiving up to 8 doses per month, 40% reported it, 13% required anti-emetic therapy, and 8% discontinued because of it. Focal hyperpigmentation was reported by 1%, including on the face, gingiva and breasts; the risk is higher with darker skin and with daily dosing, and resolution was not confirmed in some patients. The label also directs discontinuing if pregnancy is suspected, because animal reproduction studies showed fetal harm.
How does PT-141 compare with sildenafil?
This library holds no trial comparing the two head to head for efficacy. What it does hold is the population the male trials recruited: men with erectile dysfunction who had responded inadequately to sildenafil. In the 2008 intranasal trial, 342 such men were randomised and asked to take at least 16 doses; 33.5% had a positive clinical result against 8.5% on placebo, with significantly more drug-related adverse effects on bremelanotide. That is a salvage result in sildenafil non-responders rather than a comparison of the two drugs, and the intranasal formulation that produced it was never approved and is not marketed.
Is research-grade PT-141 powder the same as Vyleesi?
No. Vyleesi is a ready-to-use solution in a single-dose prefilled autoinjector, which meters the dose. A lyophilised powder sold as PT-141 has no approved label, no verified potency and no metered dose, so the milligram figure on it only means that many milligrams if the vial contains what it says. Two interactions are worth knowing first: bremelanotide may significantly decrease naltrexone exposure, so it should be avoided with orally administered naltrexone-containing products used for alcohol or opioid addiction, and it slows gastric emptying enough to reduce absorption of other oral medicines, including drugs that depend on threshold concentrations such as antibiotics.
Every number above, and where it came from
4 sources, numbered where they are used. Each one links to the paper or the label itself, not to a summary of it.
- [1]VYLEESI (bremelanotide) injection, for subcutaneous use: FDA prescribing information
2025 · FDA approved label
- [2]Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra
International Journal of Impotence Research · 2004 · Phase 1/2 clinical trial, crossover
- [3]Salvage of sildenafil failures with bremelanotide: a randomized, double-blind, placebo controlled study
The Journal of Urology · 2008 · Randomised double-blind placebo-controlled trial · n=342
- [4]Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction
International Journal of Impotence Research · 2004 · Phase 1 randomised placebo-controlled trial
The rest of the math
- Reconstitution calculatorThe full version of the tool above, with syringe barrel sizes and IU conversion.
- Vial longevityHow many doses a vial holds and the date it runs out.
- Cost per doseVial price against doses drawn, so two vial sizes can be compared honestly.
- Half-life and decayFirst-order clearance, time to steady state, and what remains at a given hour.
You worked out the draw. Now log this dose.
A calculator answers once and forgets. Dosavy keeps the concentration you mixed, the doses you actually took, and a reminder for the next one, with the same evidence labels you see on this page.