Updated March 2026

Bremelanotide (PT-141) Dosing Protocol

Q: What is the starting dose of bremelanotide (PT-141)?

The recommended starting dose for first-time users is 0.5 mg administered subcutaneously. This initial test dose allows assessment of individual tolerance, particularly for nausea and blood-pressure response. Some clinicians use a split-dose approach: inject 0.5 mg, wait 30 minutes, and if tolerated, administer an additional 0.5 mg. Users typically titrate to a therapeutic range of 1.5-1.75 mg over 2-3 subsequent administrations. The FDA-approved Vyleesi dose is 1.75 mg.

Q: What is bremelanotide's half-life?

The elimination half-life of bremelanotide is approximately 2.7 hours, with a range of 1.9 to 4.0 hours per prescribing information. Peak plasma concentration occurs at about 1 hour (range 0.5-1.0 hours) after subcutaneous injection, and SubQ bioavailability is effectively complete. Although plasma half-life is short, pharmacodynamic effects can persist up to around 16 hours (about five half-lives), and some users report residual libido-enhancing effects for 24-72 hours.

Q: What results can be expected from bremelanotide?

In RECONNECT phase 3 trials involving 1,267 premenopausal women with HSDD, bremelanotide produced statistically significant increases in sexual desire and significant reductions in distress associated with low desire (both primary endpoints p < 0.0001 vs placebo). In male ED studies, PT-141 produced significant erectogenic effects; in sildenafil non-responders, 34% of treated men reported erections sufficient for intercourse versus 9% on placebo. Combination studies with low-dose sildenafil reported over five-fold increases in erectile duration.

Q: How do you reconstitute bremelanotide (PT-141)?

Add bacteriostatic water to the lyophilized PT-141 vial using a sterile syringe. For a 10 mg vial, adding 2.0 mL BAC water yields 5 mg/mL concentration, where a 1.75 mg dose equals 0.35 mL (35 units on a U-100 insulin syringe). Direct the water stream against the glass wall, not directly onto powder. Gently swirl or roll to dissolve, never shake. Label with date and concentration, refrigerate at 2-8C, and use within 28-30 days. For custom vial and water-volume calculations, use https://www.peppal.app/calculator.

Q: Is bremelanotide (PT-141) FDA-approved?

Yes. Bremelanotide was approved by the FDA on June 21, 2019, under the brand name Vyleesi, specifically for acquired, generalized HSDD in premenopausal women, and was designated first-in-class. Use for erectile dysfunction in men, male low libido, or postmenopausal women is off-label.

Q: What are the most common side effects of bremelanotide?

The most common side effect is nausea, reported in about 40% of trial participants, with roughly 8% discontinuing treatment because of it. Other common effects include flushing (20.3%), injection-site reactions (13.2%), headache (11.3%), and vomiting (4.8%). Bremelanotide also causes transient blood-pressure increases averaging about 6/3 mmHg that resolve within about 12 hours. A unique long-term concern is hyperpigmentation, which may be irreversible in some cases.

Q: How does bremelanotide compare to Viagra/Cialis (PDE5 inhibitors)?

Bremelanotide works through a different mechanism than PDE5 inhibitors. Viagra and Cialis improve erectile blood flow by inhibiting PDE5 in peripheral vascular tissue, while bremelanotide acts centrally by activating melanocortin pathways that modulate desire and arousal. This means bremelanotide primarily targets desire and sexual motivation, while PDE5 inhibitors target erectile mechanics.

Q: What vial sizes are available for PT-141?

Research suppliers commonly offer bremelanotide (PT-141) in 5 mg and 10 mg lyophilized vial sizes. The 10 mg format is often more economical across variable dose requirements. The FDA-approved commercial product (Vyleesi) is a prefilled autoinjector containing 1.75 mg per 0.3 mL dose.

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

BAC water volume depends on vial size and target concentration. For a 10 mg vial, adding 2.0 mL creates 5 mg/mL (1.75 mg equals 35 units), while 3.0 mL creates about 3.33 mg/mL (1.75 mg is about 53 units). For a 5 mg vial, 1.0 mL creates 5 mg/mL and 2.0 mL creates 2.5 mg/mL. Higher concentrations reduce injection volume, while lower concentrations improve measurement precision. Use https://www.peppal.app/calculator for exact conversion.

Q: What is the maximum dose of bremelanotide studied?

The common maximum subcutaneous protocol dose is 2.0 mg. Early phase 1 and 2 intranasal studies used doses up to 20 mg, and early SubQ studies explored higher doses in male subjects, but the FDA-approved dose is 1.75 mg based on dose-finding efficacy and tolerability balance. Higher exposure increases side-effect burden, particularly nausea and hyperpigmentation.

Comprehensive bremelanotide (PT-141) research protocol reference covering on-demand titration (0.5-2.0 mg SubQ), reconstitution math, half-life context, side-effect percentages, and RECONNECT phase 3 evidence.

Half-life

~2.7 hours (1.9-4.0 hour range)

Dose range

0.5 mg to 2.0 mg SubQ

Status

FDA-approved for female HSDD

Class

Melanocortin receptor agonist

Need to calculate reconstitution and dosing units? Use the peptide reconstitution calculator.

Quick Reference Card

Peptide Name

Bremelanotide

Aliases

PT-141, Vyleesi, Bremelanotide Acetate

Category / Class

Melanocortin Receptor Agonist

Half-Life

~2.7 hours (range: 1.9-4.0 hours)

Dosing Frequency

On-demand (at least 45 min before activity; max 1 dose/24 hours, max 8 doses/month)

Dose Range

0.5 mg - 2.0 mg SubQ (FDA-approved: 1.75 mg)

Common Vial Sizes

5 mg, 10 mg

Route of Administration

Subcutaneous injection (abdomen or thigh)

Regulatory Status

FDA-approved (June 2019) for HSDD in premenopausal women; off-label use in men for ED/low libido.

Developer

Palatin Technologies / AMAG Pharmaceuticals

Key Stat

First-in-class melanocortin agonist and the only FDA-approved on-demand treatment that enhances sexual desire through central nervous system pathways rather than peripheral vasodilation.

Peptide Name	Bremelanotide
Aliases	PT-141, Vyleesi, Bremelanotide Acetate
Category / Class	Melanocortin Receptor Agonist
Half-Life	~2.7 hours (range: 1.9-4.0 hours)
Dosing Frequency	On-demand (at least 45 min before activity; max 1 dose/24 hours, max 8 doses/month)
Dose Range	0.5 mg - 2.0 mg SubQ (FDA-approved: 1.75 mg)
Common Vial Sizes	5 mg, 10 mg
Route of Administration	Subcutaneous injection (abdomen or thigh)
Regulatory Status	FDA-approved (June 2019) for HSDD in premenopausal women; off-label use in men for ED/low libido.
Developer	Palatin Technologies / AMAG Pharmaceuticals
Key Stat	First-in-class melanocortin agonist and the only FDA-approved on-demand treatment that enhances sexual desire through central nervous system pathways rather than peripheral vasodilation.

Peptide Partners Spotlight

COA-Verified Suppliers Carrying Bremelanotide (PT-141)

Research-grade peptide suppliers vetted for COAs, purity data, and reliability.

59 Finnrick TestsMulti-Lab Verification4 Testing Categories

Why Peptide Partners Is #1 Visit Supplier

Affiliate disclosure: some outbound supplier links are affiliate links, and we may earn a commission at no extra cost to you. This supports our free tools and protocol database. Our protocol content and editorial ratings are independent of affiliate relationships.

Preferred Partner

What Is Bremelanotide (PT-141)?

Bremelanotide (PT-141) is a synthetic melanocortin receptor agonist used to treat sexual dysfunction by targeting central nervous system pathways that regulate sexual desire and arousal. Originally known by its investigational code PT-141, the compound was developed by Palatin Technologies as a derivative of Melanotan II, a peptide initially studied for its skin-tanning properties in the 1980s and 1990s. When researchers observed that Melanotan II produced unexpected increases in sexual arousal and penile erection during tanning studies, bremelanotide was synthesized and refined specifically for its pro-sexual effects while minimizing melanogenic activity.

Structurally, bremelanotide is a cyclic heptapeptide lactam analogue of alpha-melanocyte-stimulating hormone (alpha-MSH), containing 7 amino acids with a molecular mass of 1025.16 Daltons. Its amino acid sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. The cyclic structure improves metabolic stability compared to linear peptide analogues, while deamination of the C-terminal differentiates it from its parent compound Melanotan II.

In June 2019, the FDA approved bremelanotide under the brand name Vyleesi for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, making it a first-in-class medication for this indication. The approval was based on the RECONNECT phase 3 clinical program, which demonstrated statistically significant improvements in sexual desire and reductions in distress associated with low desire (both p < 0.0001 vs placebo). Beyond its FDA-approved indication, bremelanotide has been studied in multiple phase 1 and phase 2 trials for erectile dysfunction in men, with data showing significant erectogenic effects at subcutaneous doses of 1-6 mg and intranasal doses of 7-20 mg.

This compound is FDA-approved for HSDD in premenopausal women only. Use for erectile dysfunction or male sexual dysfunction is off-label. All information on this page is for educational and research reference purposes only.

How Bremelanotide (PT-141) Works: Central Nervous System Modulation of Sexual Desire

Bremelanotide is fundamentally different from conventional sexual dysfunction treatments like PDE5 inhibitors (sildenafil, tadalafil), which work peripherally by increasing blood flow to erectile tissue. Instead, bremelanotide acts centrally in the brain, modulating neural pathways that regulate sexual motivation, desire, and arousal. This distinction is critical: bremelanotide enhances desire itself rather than only the physical mechanics of sexual function.

Melanocortin Receptor Activation (MC3R and MC4R)

Bremelanotide is a non-selective agonist of melanocortin receptors MC1 through MC5 (except MC2, the ACTH receptor), with primary activity at MC3R and MC4R. These receptors are densely expressed in the hypothalamus, including the medial preoptic area and paraventricular nucleus. When bremelanotide binds to MC4R in these regions, it activates G-protein coupled signaling cascades that increase intracellular cAMP and promote neurochemical changes that support sexual arousal and desire.

Dopaminergic Enhancement

A key downstream effect of MC3R/MC4R activation is enhanced dopamine release in mesolimbic reward pathways, particularly the medial preoptic area and nucleus accumbens. Dopamine is central to sexual motivation, desire, and reward experience. By boosting dopaminergic activity, bremelanotide amplifies natural arousal signaling and can lower the threshold for sexual interest and responsiveness.

Serotonin Modulation

Emerging evidence suggests bremelanotide may also modulate serotonergic pathways that typically inhibit sexual desire. By counteracting serotonergic suppression while enhancing dopaminergic excitation, bremelanotide creates a dual-modulation pattern that shifts neurochemistry toward sexual receptivity. This complements flibanserin's approach but through a distinct upstream pathway.

MC1R Activation and Melanogenesis

Bremelanotide activity at MC1R, the melanocortin receptor linked to melanin production, explains hyperpigmentation risk. MC1R activation can darken skin, gums, and breasts, especially with repeated dosing beyond 8 administrations per month.

The net result is centrally mediated enhancement of sexual desire and arousal that operates independently of vascular mechanisms, making bremelanotide distinct for individuals who do not respond to PDE5 inhibitors or whose dysfunction is rooted more in desire than erectile mechanics.

Tools for this Protocol

dose to units converter for reconstitution and units.
calculate injection units to lock in syringe draw volume.

Bremelanotide (PT-141) Dosing Protocol & Administration Schedule

Initial Assessment

First-ever administration

0.5 mg SubQ

At least 45-60 minutes before activity. Test tolerance for nausea, blood-pressure shifts, and flushing. Split option: 0.5 mg, wait 30 minutes, then optional additional 0.5 mg if tolerated.

Dose Titration

Second and third administrations

1.0 mg SubQ

At least 45 minutes before activity. Assess efficacy versus side effects. If response is inadequate and tolerability is acceptable, increase to 1.5 mg on a subsequent administration. If nausea is significant at 1.0 mg, remain at this dose for 2-3 more uses before increasing.

Therapeutic Range

Ongoing on-demand use

1.5-1.75 mg SubQ

At least 45 minutes before activity. This is typically the effective range; 1.75 mg is the FDA-approved dose selected for efficacy and tolerability balance.

Maximum Dose

Upper limit if lower doses are inadequate

2.0 mg SubQ

At least 45 minutes before activity. This is the common maximum recommended dose; higher doses increase nausea substantially without proportional efficacy gains.

Phase	Weeks	Weekly Dose	Notes
Initial Assessment	First-ever administration	0.5 mg SubQ	At least 45-60 minutes before activity. Test tolerance for nausea, blood-pressure shifts, and flushing. Split option: 0.5 mg, wait 30 minutes, then optional additional 0.5 mg if tolerated.
Dose Titration	Second and third administrations	1.0 mg SubQ	At least 45 minutes before activity. Assess efficacy versus side effects. If response is inadequate and tolerability is acceptable, increase to 1.5 mg on a subsequent administration. If nausea is significant at 1.0 mg, remain at this dose for 2-3 more uses before increasing.
Therapeutic Range	Ongoing on-demand use	1.5-1.75 mg SubQ	At least 45 minutes before activity. This is typically the effective range; 1.75 mg is the FDA-approved dose selected for efficacy and tolerability balance.
Maximum Dose	Upper limit if lower doses are inadequate	2.0 mg SubQ	At least 45 minutes before activity. This is the common maximum recommended dose; higher doses increase nausea substantially without proportional efficacy gains.

Important Dosing Notes

Frequency and cycle guidance: Maximum 1 dose per 24 hours, maximum 8 doses per month, commonly 4-6 doses per month, with 48-72 hour spacing to reduce melanocortin receptor desensitization. Typical onset is 30-60 minutes and primary effects often span 2-6 hours with possible residual effects for 24-72 hours. Consider discontinuation if no improvement after 8 weeks of regular use.

Why dose spacing matters: Using PT-141 more than 2-3 times per week can reduce efficacy over time. Spacing doses 48-72 hours apart may help preserve receptor sensitivity.

Nausea management: Nausea can affect up to about 40% of users, especially early. Common strategies include lower starting doses (0.5-1.0 mg), hydration, avoiding heavy meals before dosing, and clinician-guided anti-nausea support.

Hyperpigmentation risk: Exceeding 8 doses/month increases hyperpigmentation risk, and discoloration may not fully reverse after discontinuation.

Blood pressure and interaction caution: Transient BP increases around 6/3 mmHg may occur and usually resolve within about 12 hours. Avoid use in uncontrolled hypertension or significant cardiovascular disease. Gastric-motility slowing may reduce oral-drug absorption around dosing windows (including threshold-dependent oral drugs). Some peptide-clinic guidance advises avoiding concurrent PT-141 plus PDE5 injection timing due to additive blood pressure or priapism concerns.

Bremelanotide (PT-141) Reconstitution Guide

Vial Size: 5 mg

BAC Water: 1.0 mL

Concentration: 5,000 mcg/mL (5 mg/mL)

0.5 mg: 0.10 mL (10 units)

1.0 mg: 0.20 mL (20 units)

1.5 mg: 0.30 mL (30 units)

1.75 mg: 0.35 mL (35 units)

2.0 mg: 0.40 mL (40 units)

Vial Size: 5 mg

BAC Water: 2.0 mL

Concentration: 2,500 mcg/mL (2.5 mg/mL)

0.5 mg: 0.20 mL (20 units)

1.0 mg: 0.40 mL (40 units)

1.5 mg: 0.60 mL (60 units)

1.75 mg: 0.70 mL (70 units)

2.0 mg: 0.80 mL (80 units)

Vial Size: 10 mg

BAC Water: 2.0 mL

Concentration: 5,000 mcg/mL (5 mg/mL)

0.5 mg: 0.10 mL (10 units)

1.0 mg: 0.20 mL (20 units)

1.5 mg: 0.30 mL (30 units)

1.75 mg: 0.35 mL (35 units)

2.0 mg: 0.40 mL (40 units)

Vial Size: 10 mg

BAC Water: 3.0 mL

Concentration: 3,333 mcg/mL (3.33 mg/mL)

0.5 mg: 0.15 mL (15 units)

1.0 mg: 0.30 mL (30 units)

1.5 mg: 0.45 mL (45 units)

1.75 mg: 0.53 mL (53 units)

2.0 mg: 0.60 mL (60 units)

Vial Size: 10 mg

BAC Water: 4.0 mL

Concentration: 2,500 mcg/mL (2.5 mg/mL)

0.5 mg: 0.20 mL (20 units)

1.0 mg: 0.40 mL (40 units)

1.5 mg: 0.60 mL (60 units)

1.75 mg: 0.70 mL (70 units)

2.0 mg: 0.80 mL (80 units)

Vial Size: 10 mg

BAC Water: 5.0 mL

Concentration: 2,000 mcg/mL (2 mg/mL)

0.5 mg: 0.25 mL (25 units)

1.0 mg: 0.50 mL (50 units)

1.5 mg: 0.75 mL (75 units)

1.75 mg: 0.88 mL (88 units)

2.0 mg: 1.00 mL (100 units)

Vial Size	BAC Water Added	Concentration	0.5 mg Dose	1.0 mg Dose	1.5 mg Dose	1.75 mg Dose	2.0 mg Dose
5 mg	1.0 mL	5,000 mcg/mL (5 mg/mL)	0.10 mL (10 units)	0.20 mL (20 units)	0.30 mL (30 units)	0.35 mL (35 units)	0.40 mL (40 units)
5 mg	2.0 mL	2,500 mcg/mL (2.5 mg/mL)	0.20 mL (20 units)	0.40 mL (40 units)	0.60 mL (60 units)	0.70 mL (70 units)	0.80 mL (80 units)
10 mg	2.0 mL	5,000 mcg/mL (5 mg/mL)	0.10 mL (10 units)	0.20 mL (20 units)	0.30 mL (30 units)	0.35 mL (35 units)	0.40 mL (40 units)
10 mg	3.0 mL	3,333 mcg/mL (3.33 mg/mL)	0.15 mL (15 units)	0.30 mL (30 units)	0.45 mL (45 units)	0.53 mL (53 units)	0.60 mL (60 units)
10 mg	4.0 mL	2,500 mcg/mL (2.5 mg/mL)	0.20 mL (20 units)	0.40 mL (40 units)	0.60 mL (60 units)	0.70 mL (70 units)	0.80 mL (80 units)
10 mg	5.0 mL	2,000 mcg/mL (2 mg/mL)	0.25 mL (25 units)	0.50 mL (50 units)	0.75 mL (75 units)	0.88 mL (88 units)	1.00 mL (100 units)

Step-by-Step Reconstitution Instructions

Gather supplies: lyophilized PT-141 vial, bacteriostatic water, alcohol swabs, a sterile mixing syringe, and a U-100 insulin syringe for dosing.
Allow the vial to reach room temperature before opening.
Swab the rubber stoppers of both vials and allow them to dry.
Draw the desired BAC water volume (for example, 2.0 mL for a 10 mg vial to target 5 mg/mL).
Inject BAC water slowly against the glass wall, not directly onto powder.
Gently swirl or roll until dissolved. Do not shake.
Label with date/concentration and refrigerate at 2-8C (35-46F). Use within 28-30 days.

Need exact syringe units for a custom vial size or water volume? Example check: 10,000 mcg / 3.0 mL = 3,333.3 mcg/mL, and 1,750 mcg / 3,333.3 mcg/mL = 0.53 mL (53 units). Use the free Peptide Reconstitution Calculator: https://www.peppal.app/calculatorOpen Calculator

Bremelanotide (PT-141) Side Effects - What Clinical Trials Show

Bremelanotide has one of the most well-characterized safety profiles among melanocortin agonists, with data from over 20 clinical studies and more than 1,200 participants in the RECONNECT phase 3 program alone. Side effects are primarily tolerability-related rather than severe safety signals, but several require attention.

Common side effects: Nausea is the most frequently reported adverse event, occurring in about 40% of treated participants. Nausea severity often declines with repeated use, and approximately 8.1% of participants discontinued due to nausea. Other common effects include flushing (20.3%), injection-site reactions (13.2%), headache (11.3%), and vomiting (4.8%). Less common effects include cough (3.3%), fatigue (3.2%), hot flashes (2.7%), paresthesia (2.6%), dizziness (2.2%), and nasal congestion (2.1%).

Cardiovascular effects: Bremelanotide can produce a transient blood-pressure increase averaging about 6 mmHg systolic and 3 mmHg diastolic, usually returning to baseline within about 12 hours. A small transient heart-rate reduction has also been observed. It is contraindicated in uncontrolled hypertension or cardiovascular disease.

Hyperpigmentation: A melanocortin-specific risk is focal hyperpigmentation involving skin, gums, and/or breasts due to MC1R-mediated melanocyte stimulation. Risk increases above 8 doses/month and in darker baseline skin phenotypes. This discoloration may be permanent in some cases.

Hepatic effects: A rare case of acute icteric hepatitis was reported in development data and resolved after discontinuation. LiverTox classifies bremelanotide as a possible rare cause of clinically apparent liver injury.

Gastrointestinal motility: Bremelanotide slows gastric emptying, which may reduce oral absorption of concomitant medications. Documented interaction contexts include naltrexone and indomethacin.

Discontinuation profile: In RECONNECT phase 3 trials, most treatment-emergent adverse events were mild or moderate, and discontinuations were primarily tolerability-driven rather than due to severe adverse events.

Bremelanotide (PT-141) Clinical Trial Results

Diamond et al., Int J Impot Res (2004)

Phase 1 • Single-dose

24 healthy males (intranasal)

Erectile response was significant at intranasal doses over 7 mg; rigid erection duration was around 140 minutes at 20 mg versus 22 minutes placebo.

Rosen et al., Int J Impot Res (2004)

Phase 1/2 • Single-dose crossover

Healthy males plus ED patients (SubQ)

SubQ doses above 1.0 mg produced significant erectile response in healthy men; ED non-responders also showed significant response at 4 mg and 6 mg.

Diamond et al., Urology (2005)

Phase 2 • Single-dose

32 ED patients

PT-141 (7.5 mg intranasal) plus sildenafil (25 mg) outperformed sildenafil alone with over five-fold longer erectile activity.

Safarinejad & Hosseini, J Urol (2008)

Phase 2 • 12 weeks

342 ED patients (sildenafil non-responders)

34% of bremelanotide-treated subjects reported erections sufficient for intercourse vs 9% placebo, with significant IIEF improvement.

Clayton et al., Women's Health (2016)

Phase 2b • 12 weeks

397 premenopausal women with HSDD/FSAD

Dose-responsive improvements in desire/arousal/distress; 1.75 mg SubQ selected as optimal efficacy/tolerability dose.

Kingsberg et al., Obstet Gynecol (2019) RECONNECT

Phase 3 • 24 weeks

1,267 premenopausal women with HSDD

Both co-primary endpoints were met (p < 0.0001 vs placebo): improved FSFI-Desire and reduced FSDS-DAO Q13 distress.

Simon et al., Obstet Gynecol (2019) extension

Phase 3 extension • 52 weeks

RECONNECT participants

Sustained improvement in desire and distress reduction in open-label follow-up.

Trial	Phase	Duration	Population	Key Result
Diamond et al., Int J Impot Res (2004)	Phase 1	Single-dose	24 healthy males (intranasal)	Erectile response was significant at intranasal doses over 7 mg; rigid erection duration was around 140 minutes at 20 mg versus 22 minutes placebo.
Rosen et al., Int J Impot Res (2004)	Phase 1/2	Single-dose crossover	Healthy males plus ED patients (SubQ)	SubQ doses above 1.0 mg produced significant erectile response in healthy men; ED non-responders also showed significant response at 4 mg and 6 mg.
Diamond et al., Urology (2005)	Phase 2	Single-dose	32 ED patients	PT-141 (7.5 mg intranasal) plus sildenafil (25 mg) outperformed sildenafil alone with over five-fold longer erectile activity.
Safarinejad & Hosseini, J Urol (2008)	Phase 2	12 weeks	342 ED patients (sildenafil non-responders)	34% of bremelanotide-treated subjects reported erections sufficient for intercourse vs 9% placebo, with significant IIEF improvement.
Clayton et al., Women's Health (2016)	Phase 2b	12 weeks	397 premenopausal women with HSDD/FSAD	Dose-responsive improvements in desire/arousal/distress; 1.75 mg SubQ selected as optimal efficacy/tolerability dose.
Kingsberg et al., Obstet Gynecol (2019) RECONNECT	Phase 3	24 weeks	1,267 premenopausal women with HSDD	Both co-primary endpoints were met (p < 0.0001 vs placebo): improved FSFI-Desire and reduced FSDS-DAO Q13 distress.
Simon et al., Obstet Gynecol (2019) extension	Phase 3 extension	52 weeks	RECONNECT participants	Sustained improvement in desire and distress reduction in open-label follow-up.

Bremelanotide has a clinical development history spanning more than two decades. The compound was first described in the literature in 2003 under the code PT-141. Early phase 1 and 2 studies in the mid-2000s evaluated intranasal formulations in both men and women, showing central erectogenic effects in males and pro-sexual effects in females. Intranasal variability and blood-pressure lability drove reformulation to subcutaneous autoinjector delivery. Two identical phase 3 RECONNECT trials (NCT02333071 and NCT02338960) were completed in 2016, with results published in 2019. The FDA approved bremelanotide on June 21, 2019, as a first-in-class therapy. Current research focus includes off-label male ED salvage use in PDE5 non-responders and combination paradigms. Broader melanocortin-pathway development continues with related agents such as setmelanotide.

Storage & Handling

Lyophilized (powder)

-20C (-4F)

Long-term storage (years)

Lyophilized

2-8C (36-46F)

Several months

Lyophilized

<=25C (<=77F) room temperature

Up to 3 weeks (shipping/transit context)

Reconstituted

2-8C (36-46F)

28-30 days

Reconstituted - frozen aliquots

-20C (-4F)

3-4 months (single-use aliquots)

State	Temperature	Duration
Lyophilized (powder)	-20C (-4F)	Long-term storage (years)
Lyophilized	2-8C (36-46F)	Several months
Lyophilized	<=25C (<=77F) room temperature	Up to 3 weeks (shipping/transit context)
Reconstituted	2-8C (36-46F)	28-30 days
Reconstituted - frozen aliquots	-20C (-4F)	3-4 months (single-use aliquots)

Protect from light, avoid freeze-thaw cycles, and use bacteriostatic water for multi-dose workflows. The commercial Vyleesi autoinjector should be stored at or below 25C and should not be frozen. After reconstitution, the solution should remain clear and colorless; do not use cloudy, discolored, or particulate-containing solutions.

Bremelanotide (PT-141) vs. Flibanserin vs. Melanotan II

Drug Class

Bremelanotide (PT-141): Melanocortin receptor agonist

Flibanserin (Addyi): Serotonin agonist/antagonist

Melanotan II: Non-selective melanocortin receptor agonist

Route

Bremelanotide (PT-141): Subcutaneous injection

Flibanserin (Addyi): Oral tablet (daily)

Melanotan II: Subcutaneous injection

Dosing Schedule

Bremelanotide (PT-141): On-demand

Flibanserin (Addyi): Daily at bedtime

Melanotan II: On-demand or periodic

Half-Life

Bremelanotide (PT-141): ~2.7 hours

Flibanserin (Addyi): ~11 hours

Melanotan II: ~33 minutes (IV; longer effect window SubQ)

FDA Status

Bremelanotide (PT-141): Approved (2019) for HSDD in premenopausal women

Flibanserin (Addyi): Approved (2015) for HSDD in premenopausal women

Melanotan II: Not FDA-approved

Primary Mechanism

Bremelanotide (PT-141): MC3R/MC4R activation with dopamine enhancement

Flibanserin (Addyi): Increases dopamine/norepinephrine and decreases serotonin

Melanotan II: MC1-MC5 activation with melanogenesis and sexual arousal

Onset

Bremelanotide (PT-141): 30-60 minutes

Flibanserin (Addyi): 4-8 weeks for full effect

Melanotan II: 1-2 hours

Alcohol Interaction

Bremelanotide (PT-141): No clinically meaningful interaction

Flibanserin (Addyi): Contraindicated with alcohol

Melanotan II: No known interaction

Key Side Effect

Bremelanotide (PT-141): Nausea (40%), hyperpigmentation

Flibanserin (Addyi): Dizziness, somnolence, hypotension

Melanotan II: Nausea, tanning, spontaneous erections

Efficacy in Men

Bremelanotide (PT-141): Phase 1/2 male data and growing off-label use

Flibanserin (Addyi): Very limited male data

Melanotan II: Anecdotal and limited trial data

Unique Advantage

Bremelanotide (PT-141): On-demand use with central desire modulation

Flibanserin (Addyi): Only oral option

Melanotan II: Dual tanning plus sexual-arousal effects

Feature	Bremelanotide (PT-141)	Flibanserin (Addyi)	Melanotan II
Drug Class	Melanocortin receptor agonist	Serotonin agonist/antagonist	Non-selective melanocortin receptor agonist
Route	Subcutaneous injection	Oral tablet (daily)	Subcutaneous injection
Dosing Schedule	On-demand	Daily at bedtime	On-demand or periodic
Half-Life	~2.7 hours	~11 hours	~33 minutes (IV; longer effect window SubQ)
FDA Status	Approved (2019) for HSDD in premenopausal women	Approved (2015) for HSDD in premenopausal women	Not FDA-approved
Primary Mechanism	MC3R/MC4R activation with dopamine enhancement	Increases dopamine/norepinephrine and decreases serotonin	MC1-MC5 activation with melanogenesis and sexual arousal
Onset	30-60 minutes	4-8 weeks for full effect	1-2 hours
Alcohol Interaction	No clinically meaningful interaction	Contraindicated with alcohol	No known interaction
Key Side Effect	Nausea (40%), hyperpigmentation	Dizziness, somnolence, hypotension	Nausea, tanning, spontaneous erections
Efficacy in Men	Phase 1/2 male data and growing off-label use	Very limited male data	Anecdotal and limited trial data
Unique Advantage	On-demand use with central desire modulation	Only oral option	Dual tanning plus sexual-arousal effects

These compounds represent distinct pharmacological approaches to sexual dysfunction and are not interchangeable.

Bremelanotide offers on-demand dosing and a phase 3-characterized safety profile, while flibanserin requires daily use for weeks and carries a major alcohol contraindication.

Melanotan II remains an unregulated research compound with broader receptor activation and less controlled safety data than bremelanotide.

See the Melanotan II protocol for compound-specific guides.

Frequently Asked Questions - Bremelanotide (PT-141)

Q1: What is the starting dose of bremelanotide (PT-141)?

The recommended starting dose for first-time users is 0.5 mg administered subcutaneously. This initial test dose allows assessment of individual tolerance, particularly for nausea and blood-pressure response. Some clinicians use a split-dose approach: inject 0.5 mg, wait 30 minutes, and if tolerated, administer an additional 0.5 mg. Users typically titrate to a therapeutic range of 1.5-1.75 mg over 2-3 subsequent administrations. The FDA-approved Vyleesi dose is 1.75 mg.

Q2: What is bremelanotide's half-life?

The elimination half-life of bremelanotide is approximately 2.7 hours, with a range of 1.9 to 4.0 hours per prescribing information. Peak plasma concentration occurs at about 1 hour (range 0.5-1.0 hours) after subcutaneous injection, and SubQ bioavailability is effectively complete. Although plasma half-life is short, pharmacodynamic effects can persist up to around 16 hours (about five half-lives), and some users report residual libido-enhancing effects for 24-72 hours.

Q3: What results can be expected from bremelanotide?

In RECONNECT phase 3 trials involving 1,267 premenopausal women with HSDD, bremelanotide produced statistically significant increases in sexual desire and significant reductions in distress associated with low desire (both primary endpoints p < 0.0001 vs placebo). In male ED studies, PT-141 produced significant erectogenic effects; in sildenafil non-responders, 34% of treated men reported erections sufficient for intercourse versus 9% on placebo. Combination studies with low-dose sildenafil reported over five-fold increases in erectile duration.

Q4: How do you reconstitute bremelanotide (PT-141)?

Add bacteriostatic water to the lyophilized PT-141 vial using a sterile syringe. For a 10 mg vial, adding 2.0 mL BAC water yields 5 mg/mL concentration, where a 1.75 mg dose equals 0.35 mL (35 units on a U-100 insulin syringe). Direct the water stream against the glass wall, not directly onto powder. Gently swirl or roll to dissolve, never shake. Label with date and concentration, refrigerate at 2-8C, and use within 28-30 days. For custom vial and water-volume calculations, use https://www.peppal.app/calculator.

Q5: Is bremelanotide (PT-141) FDA-approved?

Yes. Bremelanotide was approved by the FDA on June 21, 2019, under the brand name Vyleesi, specifically for acquired, generalized HSDD in premenopausal women, and was designated first-in-class. Use for erectile dysfunction in men, male low libido, or postmenopausal women is off-label.

Q6: What are the most common side effects of bremelanotide?

The most common side effect is nausea, reported in about 40% of trial participants, with roughly 8% discontinuing treatment because of it. Other common effects include flushing (20.3%), injection-site reactions (13.2%), headache (11.3%), and vomiting (4.8%). Bremelanotide also causes transient blood-pressure increases averaging about 6/3 mmHg that resolve within about 12 hours. A unique long-term concern is hyperpigmentation, which may be irreversible in some cases.

Q7: How does bremelanotide compare to Viagra/Cialis (PDE5 inhibitors)?

Bremelanotide works through a different mechanism than PDE5 inhibitors. Viagra and Cialis improve erectile blood flow by inhibiting PDE5 in peripheral vascular tissue, while bremelanotide acts centrally by activating melanocortin pathways that modulate desire and arousal. This means bremelanotide primarily targets desire and sexual motivation, while PDE5 inhibitors target erectile mechanics.

Q8: What vial sizes are available for PT-141?

Research suppliers commonly offer bremelanotide (PT-141) in 5 mg and 10 mg lyophilized vial sizes. The 10 mg format is often more economical across variable dose requirements. The FDA-approved commercial product (Vyleesi) is a prefilled autoinjector containing 1.75 mg per 0.3 mL dose.

Q9: How much bacteriostatic water should be added to a PT-141 vial?

BAC water volume depends on vial size and target concentration. For a 10 mg vial, adding 2.0 mL creates 5 mg/mL (1.75 mg equals 35 units), while 3.0 mL creates about 3.33 mg/mL (1.75 mg is about 53 units). For a 5 mg vial, 1.0 mL creates 5 mg/mL and 2.0 mL creates 2.5 mg/mL. Higher concentrations reduce injection volume, while lower concentrations improve measurement precision. Use https://www.peppal.app/calculator for exact conversion.

Q10: What is the maximum dose of bremelanotide studied?

The common maximum subcutaneous protocol dose is 2.0 mg. Early phase 1 and 2 intranasal studies used doses up to 20 mg, and early SubQ studies explored higher doses in male subjects, but the FDA-approved dose is 1.75 mg based on dose-finding efficacy and tolerability balance. Higher exposure increases side-effect burden, particularly nausea and hyperpigmentation.

Q11: How should reconstituted bremelanotide (PT-141) be stored?

Reconstituted bremelanotide should be refrigerated at 2-8C (36-46F) and used within 28-30 days. Use bacteriostatic water for multi-dose workflows, protect from light, and avoid repeated freeze-thaw cycles. Single-use frozen aliquots at -20C can be used for longer storage windows in some protocols.

Q12: What were the key clinical trials for bremelanotide?

The pivotal trials were the two phase 3 RECONNECT studies (NCT02333071 and NCT02338960) in a combined 1,267 premenopausal women with HSDD, evaluating 1.75 mg subcutaneous bremelanotide over 24 weeks. Both met co-primary endpoints with significant improvements in desire and distress outcomes (p < 0.0001 vs placebo). A 52-week open-label extension reported sustained efficacy and safety. Earlier phase 1 and phase 2 male ED studies by Diamond, Rosen, and Safarinejad established erectogenic effects and informed later protocol interest.

Sources & Research

Kingsberg SA, Clayton AH, Portman D, et al. "Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials." Obstetrics & Gynecology, 2019 DOI: 10.1097/AOG.0000000000003500.
Simon JA, Kingsberg SA, Portman D, et al. "Long-term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder." Obstetrics & Gynecology, 2019 DOI: 10.1097/AOG.0000000000003514.
Dhillon S, Keam SJ. "Bremelanotide: First Approval." Drugs, 2019 PubMed.
Clayton AH, Althof SE, Kingsberg S, et al. "Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women: A Randomized, Placebo-Controlled Dose-Finding Trial." Women's Health, 2016.
Diamond LE, Earle DC, Rosen RC, et al. "Double-blind, Placebo-Controlled Evaluation of Intranasal PT-141 in Healthy Males and Patients with Mild-to-Moderate Erectile Dysfunction." International Journal of Impotence Research, 2004 PubMed.
Rosen RC, Diamond LE, Earle DC, et al. "Evaluation of Subcutaneous PT-141 in Healthy Male Subjects and Viagra Non-Responders." International Journal of Impotence Research, 2004 PubMed.
Diamond LE, Earle DC, Garcia WD, Spana C. "Co-administration of Low Doses of Intranasal PT-141 and Sildenafil Produces Enhanced Erectile Response." Urology, 2005 PubMed.
Safarinejad MR, Hosseini SY. "Salvage of Sildenafil Failures with Bremelanotide: A Randomized, Double-blind, Placebo Controlled Study." The Journal of Urology, 2008 PubMed.
U.S. Food and Drug Administration. VYLEESI (bremelanotide injection) prescribing information. Label PDF.
ClinicalTrials.gov. RECONNECT Study 301 (NCT02333071). Trial.
ClinicalTrials.gov. RECONNECT Study 302 (NCT02338960). Trial.
Koochaki P, Revicki D, Wilson H, et al. "The Patient Experience of Premenopausal Women Treated with Bremelanotide for Hypoactive Sexual Desire Disorder: RECONNECT Exit Study Results." Journal of Women's Health, 2021 PubMed.
Giuliano F. "Control of Penile Erection by the Melanocortinergic System: Experimental Evidences and Therapeutic Perspectives." Journal of Andrology, 2004 DOI: 10.1002/j.1939-4640.2004.tb02842.x.
Bremelanotide. Wikipedia. Link.

Related Protocols

~33 min (IV)

Melanotan II

Melanocortin Agonist

View protocol

~28 min

Kisspeptin-10

GnRH Stimulator / Sexual Health

View protocol

~3-5 min

Oxytocin

Neuropeptide / Bonding & Intimacy

View protocol

~3-5 hours

Sildenafil (reference)

PDE5 Inhibitor

View protocol

Short (topical)

GHK-Cu

Tissue Repair Peptide

View protocol

~4 hours

BPC-157

Tissue Repair / Cytoprotection

View protocol

Convert this protocol into exact units and save it in Pep Pal with the Pep Pal calculator.

Disclaimer

The information on this page is for educational and research reference purposes only. Bremelanotide (PT-141) is FDA-approved for hypoactive sexual desire disorder (HSDD) in premenopausal women under the brand name Vyleesi. Use for erectile dysfunction, male sexual dysfunction, or in postmenopausal women is off-label and not part of the FDA-approved indication. No compounds discussed on this site are intended for unsupervised human consumption. This is not medical advice. Consult a qualified healthcare professional before considering any peptide protocol.

This site contains affiliate links to vetted peptide suppliers. We may earn a commission at no extra cost to you. Our protocol content and editorial ratings are independent of affiliate relationships.