Hormonal · Dosing reference

PT-141 dosage

Dosing as the FDA label states it, how long trials ran, and the arithmetic for working with vials.

FDA-approvedAHuman trial evidenceFDA label

Full research page Cycle-length evidence Compare Prefer Amiravo on Google

Regulatory status: FDA-approved
Human amounts: 1.75 mg subcutaneously as needed, at least 45 minutes before anticipated sexual activity; no more than one dose in 24 hours or 8 per month (FDA label) ¹
Route studied: Subcutaneous (single-dose autoinjector)
Frequency: As needed; at most one dose per 24 hours
Half-life: Mean terminal half-life of about 2.7 hours (range 1.9 to 4.0 hours) after a single subcutaneous administration, per the FDA label ^1.
Evidence grade: Grade A · Human trial evidence
Vial sizes on the market: 10 mg
Other forms seen: Liquid spray 10 mL (10 mg)

What PT-141 is

PT-141 is the research name for bremelanotide, a cyclic melanocortin receptor agonist that the FDA approved in 2019 as Vyleesi for a narrowly defined form of low sexual desire in premenopausal women. Its mechanism in HSDD is not known, and its main documented adverse reactions are nausea, flushing, headache, injection site reactions and transient blood pressure changes. This entry summarizes the FDA label, the pivotal trials and the earlier preclinical and male erectile dysfunction studies.

Bremelanotide is a melanocortin receptor agonist that activates several receptor subtypes without strong selectivity; the label gives an order of potency of MC1R, MC4R, MC3R, MC5R and MC2R, and states that binding at MC1R and MC4R is most relevant at therapeutic dose levels ^1. The label also states that the mechanism by which bremelanotide improves HSDD in women is unknown ^1. Central nervous system activity… How it works →

Key evidence

Kingsberg et al., Obstetrics & Gynecology · 2019 · Humans (premenopausal women with acquired, generalized HSDD)
Of 1,267 women randomized, bremelanotide was associated with statistically significant increases in desire score (integrated difference 0.35) and reductions in desire-related distress (integrated difference -0.33) compared with placebo; nausea, flushing and headache were reported by 10% or more of treated women ^2. ²
Simon et al., Obstetrics & Gynecology · 2019 · Humans (women who completed the RECONNECT core phase)
No new safety signals were reported; the most common treatment-related adverse events were nausea (40.4%), flushing (20.6%) and headache (12.0%), and analyses were descriptive only ^3. ³
Diamond et al., International Journal of Impotence Research · 2004 · Humans (healthy men and men with mild-to-moderate erectile dysfunction)
Erectile responses were statistically greater than placebo at higher intranasal doses, onset was around 30 minutes, mean half-life was 1.85 to 2.09 hours, and flushing and nausea were the most common adverse events ^4. ⁴

All studies on the research page

Schedules by time period

Label regimens and laid out week by week. Each bar is what the label states or what investigators gave participants; none is a recommendation.

FDA label

Vyleesi (bremelanotide) (FDA label): as-needed dosing ¹

Premenopausal women with acquired, generalized hypoactive sexual desire disorder

As needed

SC · as needed (not more than one dose within 24 hours)

1.75 mg · As needed, at least 45 minutes before anticipated sexual activity

The label says not more than one dose within 24 hours and that more than 8 doses per month is not recommended; discontinue after 8 weeks if no improvement is reported. Not a time-based schedule.

Dosing as stated on the FDA label

For premenopausal women with acquired, generalized HSDD (Vyleesi): 1.75 mg administered subcutaneously, as needed, at least 45 minutes before anticipated sexual activity. ¹
For premenopausal women with acquired, generalized HSDD (Vyleesi): do not administer more than one dose within 24 hours; administering more than 8 doses per month is not recommended. ¹
For premenopausal women with acquired, generalized HSDD (Vyleesi): discontinue after 8 weeks if the patient does not report an improvement in symptoms. ¹
For premenopausal women with acquired, generalized HSDD (Vyleesi): supplied as a single-dose prefilled autoinjector containing 1.75 mg/0.3 mL clear solution, self-administered; the label advises discarding the solution if it is cloudy, discolored or contains visible particles. ¹

How long did human studies run?

No human study durations are recorded for PT-141.

Cycle-length evidence for PT-141

Side effects reported in studies

Nausea
40.0% vs 1.3% placebo · Pooled phase 3 RECONNECT trials, premenopausal women with HSDD (n = 627 vs 620) ¹
Flushing
20.3% vs 0.3% placebo · Pooled phase 3 trials ¹
Injection site reactions
13.2% vs 8.4% placebo · Pooled phase 3 trials ¹
Headache
11.3% vs 1.9% placebo · Pooled phase 3 trials ¹
Vomiting
4.8% vs 0.2% placebo · Pooled phase 3 trials ¹
Focal hyperpigmentation
1% vs none with placebo (phase 3); 38% after 8 consecutive daily doses in a separate clinical study · Premenopausal women ¹
Any adverse reaction leading to discontinuation
18% vs 2% placebo · Pooled phase 3 trials ¹
Acute hepatitis (single case)
One case in the open-label extension · Woman with 10 doses over one year ¹

Full adverse-event data

PT-141 draw calculator

Pick the vial strength and the water added, enter an amount, and see the concentration, the units to draw and how many draws the vial holds. Arithmetic only.

1 · Vial strength

sizes on the market

2 · Water added

3 · Amount per draw

4 · Syringe

Your mix

10 mg + 2 mL water = 5 mg/mL

10 units holds 0.5 mg (500 mcg)

Draw toEnter an amount in step 3

U-100 syringe · 100 units = 1 mL

Computed from your inputs. Not a dose or a recommendation.

Compare water volumes for this vialShow

More water = lower concentration = a larger, easier-to-measure draw. Tap a row to use it.

Water	mg/mL	Draw
0.5 mL	20	—
1 mL	10	—
1.5 mL	6.667	—
2 mL	5	—
2.5 mL	4	—
3 mL	3.333	—
5 mL	2	—

Supplies and handling

Lyophilized vial
Sealed vial with the freeze-dried cake. Check the label, lot and the certificate of analysis before opening.
Sterile diluent
The diluent named on the product documentation. Bacteriostatic water contains benzyl alcohol; sterile water does not.
Graduated syringes
Sized to the volume being measured. U-100 insulin syringes are graduated in units where 100 units = 1 mL.
Alcohol prep pads
For wiping vial stoppers before each puncture.
Nitrile gloves
Clean gloves for aseptic handling.
Sharps container
Puncture-resistant container for used needles.

Step-by-step reconstitution guide Storage and transport accessories

Storage

Handling of research-grade lyophilized peptide generally follows the supplier's documentation, which should be treated as authoritative. The FDA-approved Vyleesi product is a single-dose autoinjector, and its storage is governed by the prescribing information rather than by research-supplier guidance.

Lyophilized (unmixed) vials: typically stored cold and dry, away from light, as the documentation directs. Many are stable longer frozen.
Reconstituted vials: typically refrigerated (about 2–8 °C), protected from light and not frozen.
Bacteriostatic water contains benzyl alcohol, which inhibits bacterial growth in multi-use vials; sterile water has no preservative.

Handling mistakes and troubleshooting

Added the wrong volume of diluent: The concentration changes, not the amount of compound in the vial. Recalculate with the volume actually added and relabel the vial.
Shook the vial and it foamed: Let it settle in the refrigerator. Foam is a sign of agitation; some peptides aggregate when shaken. Note it on the label.
The solution is cloudy or has particles: Do not use it. Cloudiness can indicate incomplete dissolution, contamination or degradation. Record the lot and contact the supplier with the certificate of analysis.
The powder cake looks melted or shrunken before reconstitution: This can indicate the vial was exposed to heat or moisture. Record the lot and condition on arrival.
Liquid sprayed back when the needle was removed: Pressure built up in the vial. Withdraw a small volume of air while adding diluent to keep pressure neutral.

Regulatory status

Status: Approved by the FDA in 2019 as Vyleesi (bremelanotide injection) for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD); the label states it is not indicated for HSDD in postmenopausal women or in men, and not to enhance sexual performance ^1.
United States (FDA): Approved in 2019 as Vyleesi (bremelanotide injection), a prescription product, for premenopausal women with acquired, generalized HSDD ^1. A DailyMed search conducted for this entry returned one bremelanotide label, for Vyleesi ^1.
Sport (WADA): The 2026 WADA Prohibited List text reviewed does not name bremelanotide ^12. Its S0 class covers pharmacological substances with no current approval by any governmental regulatory health authority for human therapeutic use, and bremelanotide holds an FDA approval; athletes subject to anti-doping rules should confirm status with their anti-doping organization ^12.

Status varies by country and changes over time. How we describe regulatory status.

PT-141 compared with related compounds

Compound	Status	Evidence	Human amounts	Half-life
PT-141	FDA-approved	A	FDA label	Mean terminal half-life of about 2.7 hou
Melanotan II	Not approved — research use only	B	None established	—
Melanotan I	Not approved — research use only	—	None established	—
Kisspeptin-54	Not approved — research use only	B	None established	About 28 minutes (intravenous, healthy m
Apelin-13	Not approved — research use only	B	None established	Not located as a numeric value in the so
hCG (human chorionic gonadotropin)	FDA-approved	A	FDA label	About 29 hours (recombinant hCG, subcuta

Frequently asked questions

What doses of PT-141 have been studied in humans?

PT-141 is FDA-approved, so the label states the dosing for the approved product. This page quotes it, with citations. It does not apply to research-grade material.

Is there an established PT-141 cycle length?

No. We found no human studies that report treatment duration for PT-141.

How much bacteriostatic water should be added to a PT-141 vial?

There is no compound-specific volume. The diluent volume only sets the concentration: concentration = mass in the vial ÷ volume added (for example, 10 mg in 2 mL gives 5 mg/mL). The calculator on this page shows the arithmetic for any combination.

How many units is a given amount on an insulin syringe?

On a U-100 syringe, 100 units = 1 mL. Units for an amount = amount ÷ (concentration per unit). The calculator converts any amount you enter at the concentration you choose; a unit is a volume mark, not an amount of compound.

What is the half-life of PT-141?

Mean terminal half-life of about 2.7 hours (range 1.9 to 4.0 hours) after a single subcutaneous administration, per the FDA label ^1.

Is PT-141 FDA-approved?

FDA-approved. Approved by the FDA in 2019 as Vyleesi (bremelanotide injection) for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD); the label states it is not indicated for HSDD in postmenopausal women or in men, and not to enhance sexual performance ^1.

References

VYLEESI (bremelanotide injection) prescribing information FDA label (DailyMed). 2024
Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials Obstet Gynecol. 2019
Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder Obstet Gynecol. 2019
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 Int J Impot Res. 2004
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 Int J Impot Res. 2004
Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist Proc Natl Acad Sci U S A. 2004
Bremelanotide: an overview of preclinical CNS effects on female sexual function J Sex Med. 2007
PT-141: a melanocortin agonist for the treatment of sexual dysfunction Ann N Y Acad Sci. 2003
Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization Peptides. 2006
Study to Evaluate the Efficacy/Safety of Bremelanotide in Premenopausal Women With Hypoactive Sexual Desire Disorder (Study 301) ClinicalTrials.gov NCT02333071. 2015
Study to Evaluate the Efficacy/Safety of Bremelanotide in Premenopausal Women With Hypoactive Sexual Desire Disorder (Study 302) ClinicalTrials.gov NCT02338960. 2015
WADA Prohibited List US Food and Drug Administration. 2026
Bremelanotide (CID 9941379) PubChem. 2026

Last reviewed October 22, 2026 by the Amiravo editorial team. Editorial policy · Report an error