The approved PT-141 dosage is 1.75 mg under the skin, given at least 45 minutes before sex, no more than once in 24 hours and no more than 8 times a month. That's the Vyleesi label, and it covers one group of patients. We'd read those caps as part of the dose.
PT-141 does have an approved human dose. As Vyleesi, bremelanotide is labeled at 1.75 mg under the skin, at least 45 minutes before sex. No more than one dose in 24 hours, and no more than 8 doses a month. The caps are part of it.
What is the approved PT-141 dose?
PT-141 was approved in 2019, as Vyleesi, for premenopausal women with acquired, generalized hypoactive sexual desire disorder. The prescribing information sets out the dose and the rules around it together, so you get both or neither.
| What the label specifies | The value |
|---|---|
| Dose | 1.75 mg |
| Route and device | Subcutaneous, abdomen or thigh, prefilled single-dose autoinjector |
| Presentation | 1.75 mg in 0.3 mL of clear solution |
| Timing | As needed, at least 45 minutes before anticipated sexual activity |
| Maximum frequency | One dose per 24 hours; more than 8 doses per month not recommended |
| Stopping rule | Discontinue after 8 weeks if the patient reports no improvement |
| Contraindications | Uncontrolled hypertension or known cardiovascular disease |
Even inside an approved label, the honest reading is narrower than it looks. Read how careful the FDA's own text is about what's settled.
The duration of efficacy after each dose is unknown and the optimal window for VYLEESI administration has not been fully characterized.
U.S. Food and Drug Administration, Vyleesi prescribing information, 2019That's an approved drug saying it doesn't know how long a dose lasts. We'd use it as calibration for how much any unapproved compound's dosing chart can possibly know.
Why are the PT-141 dose limits part of the dose?
PT-141's monthly cap isn't a formality. The label ties it to two problems that scale with dose frequency: focal hyperpigmentation, and the hours each month spent with blood pressure raised.
Skin darkening was reported by 1% of patients taking up to eight doses a month. It appeared on the face, gums and breasts, with higher risk in darker skin and with daily dosing. Resolution wasn't confirmed in some patients.
Bremelanotide transiently raises blood pressure after every dose. The label reports a maximal rise of 6 mmHg systolic and 3 mmHg diastolic, peaking 2 to 4 hours after the injection. Heart rate falls by up to 5 beats a minute.
Both usually return to baseline within 12 hours. That's why the drug is contraindicated in uncontrolled hypertension and known cardiovascular disease, and why dosing more often means more hours per month with pressure raised.
The label also carries a stopping rule, which almost no unapproved dosing chart does.
Discontinue VYLEESI after 8 weeks if the patient does not report an improvement in her symptoms.
U.S. Food and Drug Administration, Vyleesi prescribing information, 2019
PT-141
The bremelanotide discussed throughout this article, supplied as a research compound with a certificate of analysis matched to the lot.
Does a higher PT-141 dose do more?
PT-141's pharmacokinetics answer the question people usually ask next, and the answer is no.
- Exposure stops tracking dose. Plasma concentrations rise less than proportionally across the studied range of 0.3 to 10 mg, and peak concentration plateaus at 7.5 mg — about 4.3 times the maximum recommended dose. Past that point, more compound does not become more exposure.
- It clears fast. Mean terminal half-life is 2.7 hours, with a range of 1.9 to 4.0. Median time to peak is about one hour, which is why the label puts the injection 45 minutes ahead of activity.
- Absorption is essentially complete. Bioavailability after subcutaneous injection is around 100%, and the injection site — abdomen or thigh — made no significant difference to exposure.
Mean peak concentration at the approved dose is 72.8 ng/mL, with an area under the curve of 276 hr·ng/mL. Those are the numbers a dose-response chart would have to beat to justify itself.
The label already shows the curve flattening well below the point most escalation schedules assume.
What did the approved PT-141 dose cost in tolerability?
Approval came from two identical 24-week randomized, double-blind, placebo-controlled trials in 1,247 premenopausal women, registered as NCT02333071 and NCT02338960. Participants self-injected 1.75 mg or placebo as needed. The median was 10 injections across 24 weeks; most used it two to three times a month.
The tolerability figures from those trials are the part that rarely survives into a dosing chart:
| Adverse reaction | Bremelanotide 1.75 mg (n=627) | Placebo (n=620) |
|---|---|---|
| Nausea | 40.0% | 1.3% |
| Flushing | 20.3% | 0.3% |
| Injection site reactions | 13.2% | 8.4% |
| Headache | 11.3% | 1.9% |
| Vomiting | 4.8% | 0.2% |
| Discontinued for adverse reactions | 18% | 2% |
Independent re-analysis has been unkind to the efficacy side of that trade. Spielmans worked from the FDA New Drug Application rather than the sponsor's publication.
That re-analysis found adverse-event-induced discontinuation far higher on drug: an odds ratio of 11.98, and a number needed to harm of 6. Participants were also more likely to enter the open-label extension after placebo than after bremelanotide.
Bremelanotide's modest benefits on incompletely reported post-hoc measures of questionable validity in combination with participants substantially preferring to take placebo suggest that the drug is generally not useful.
Spielmans, Journal of Sex Research, 2021How does research-grade PT-141 differ?
Research-grade PT-141 shares the molecule with Vyleesi and none of the rest. The approved dose belongs to a specific product, in a specific population, in a specific form. If you're reading the label across to a vial, that's the gap.
- Form. Vyleesi is a sterile solution, 1.75 mg in 0.3 mL, in a single-dose autoinjector. Research material is lyophilized powder, typically 10 mg a vial — about 5.7 labeled doses' worth of compound, to be reconstituted and measured by hand.
- Population. The label is explicit that the drug is not indicated for HSDD in postmenopausal women or in men, and not indicated to enhance sexual performance. A dose approved for one group is not evidence of a dose for another.
- Identity. Forensic work using high-resolution mass spectrometry has characterized bremelanotide and melanotan II seized from the performance-and-image-enhancing-drug market, where the two circulate alongside each other. They are different molecules with different effects on pigmentation.
What travels between the two is the pharmacology: the half-life, the plateau above 7.5 mg, the blood pressure response, the nausea rate.
What doesn't travel is the assurance that the vial holds what the label would have guaranteed. That's what a batch-matched certificate of analysis is for. Our guides to reading a COA and where to buy PT-141 cover that ground.
PT-141
Research-use-only material, sold by the vial with batch documentation. Check the certificate of analysis against the batch you receive.
What to know now
- PT-141 has an approved human dose. Vyleesi is labeled at 1.75 mg subcutaneously, at least 45 minutes before sexual activity, in a single-dose autoinjector.
- The caps are part of the dose: one injection per 24 hours, no more than 8 a month, and stop at 8 weeks without improvement.
- More is not more. Exposure rises less than proportionally from 0.3 to 10 mg and peak concentration plateaus at 7.5 mg.
- Nausea hit 40% against 1.3% on placebo, and 18% of patients stopped for adverse reactions against 2%.
- The approval covers premenopausal women with acquired, generalized HSDD. The label states it is not indicated in men, in postmenopausal women, or to enhance performance.
What we're watching
We're watching two things. First, whether any registered program produces a labeled PT-141 dose in men. The trials that ran didn't make the regulatory case, and until one does there's no approved male dose to report.
Second, whether post-marketing surveillance sharpens the hyperpigmentation picture at label frequency. The label already flags that resolution wasn't confirmed in some patients, and that the risk rises with dosing frequency.
Frequently asked questions
What is the PT-141 dose?
As the approved drug Vyleesi: 1.75 mg injected subcutaneously into the abdomen or thigh, at least 45 minutes before anticipated sexual activity. No more than once in 24 hours, and no more than 8 times a month.
How long before does PT-141 need to be given?
The label says at least 45 minutes before anticipated sexual activity. Median time to peak plasma concentration is about one hour. The label also states plainly that the duration of efficacy after each dose is unknown.
Is there an approved PT-141 dose for men?
No, and we can't give you one. The Vyleesi label states the drug isn't indicated for HSDD in postmenopausal women or in men, and isn't indicated to enhance sexual performance. Trials in men didn't produce an approval, so no labeled male dose exists.
Does a higher dose do more?
PT-141's own label says no. Plasma concentrations rise less than proportionally between 0.3 and 10 mg, and peak concentration plateaus at 7.5 mg, roughly 4.3 times the maximum recommended dose.
Why is the monthly limit 8 doses?
The label ties the PT-141 cap to dose frequency. More frequent dosing raises the risk of focal hyperpigmentation, and adds hours per month with blood pressure elevated. Few patients in the Phase 3 program exceeded 8 doses a month.
References
- U.S. Food and Drug Administration. (2019). Vyleesi (bremelanotide injection) prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/210557s000lbl.pdf
- Simon, J. A., Kingsberg, S. A., Portman, D., et al. (2022). Prespecified and integrated subgroup analyses from the RECONNECT phase 3 studies of bremelanotide. Journal of Women's Health, 31(3), 391–400. https://doi.org/10.1089/jwh.2021.0225
- Clayton, A. H., Kingsberg, S. A., Portman, D., et al. (2022). Safety profile of bremelanotide across the clinical development program. Journal of Women's Health, 31(2), 171–182. https://doi.org/10.1089/jwh.2021.0191
- Spielmans, G. I. (2021). Re-analyzing phase III bremelanotide trials for "hypoactive sexual desire disorder" in women. Journal of Sex Research, 58(9), 1085–1105. https://doi.org/10.1080/00224499.2021.1885601
- Spielmans, G. I., & Ellefson, E. M. (2024). Small effects, questionable outcomes: Bremelanotide for hypoactive sexual desire disorder. Journal of Sex Research, 61(4), 540–561. https://doi.org/10.1080/00224499.2023.2175192
- Pfaus, J. G., Sadiq, A., Spana, C., & Clayton, A. H. (2022). The neurobiology of bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women. CNS Spectrums, 27(3), 281–289. https://doi.org/10.1017/S109285292100002X
- Cipriani, S., Alfaroli, C., Maseroli, E., & Vignozzi, L. (2023). An evaluation of bremelanotide injection for the treatment of hypoactive sexual desire disorder. Expert Opinion on Pharmacotherapy, 24(1), 15–21. https://doi.org/10.1080/14656566.2022.2132144
- Pettigrew, J. A., & Novick, A. M. (2021). Hypoactive sexual desire disorder in women: Physiology, assessment, diagnosis, and treatment. Journal of Midwifery & Women's Health, 66(6), 740–748. https://doi.org/10.1111/jmwh.13283
- Mestria, S., Odoardi, S., Frison, G., & Strano Rossi, S. (2021). LC-HRMS characterization of melanotan II and bremelanotide sold on the black market. Drug Testing and Analysis, 13(4), 876–882. https://doi.org/10.1002/dta.2986