Bremelanotide

Overview

Bremelanotide (PT-141) is a synthetic cyclic heptapeptide developed in the early 2000s by Palatin Technologies as a centrally-acting treatment for sexual dysfunction [1]. It was created directly from Melanotan II (MT-II) research: investigators recognized that MT-II produced strong spontaneous erections but carried an unacceptable safety profile — particularly unwanted skin darkening from melanogenesis. Researchers isolated an active metabolite of MT-II to produce PT-141, which retains the central sexual-response effects without triggering tanning [1][2].

In June 2019, the FDA approved bremelanotide (brand name Vyleesi) as a subcutaneous injection for the treatment of acquired, generalized Hypoactive Sexual Desire Disorder (HSDD) in premenopausal women, following the pivotal Phase 3 RECONNECT trials [4]. Palatin Technologies sold the worldwide commercial rights to Cosette Pharmaceuticals in late 2023, which now handles manufacturing and distribution.

The FDA approval applies exclusively to the subcutaneous injection formulation. Intranasal development was halted by the FDA in 2007 due to unacceptable blood-pressure elevations observed in clinical testing.

Research Areas and Claims

Clinic marketing positions bremelanotide as a general-purpose “libido shot” for men and women, and as an alternative to PDE5 inhibitors (sildenafil, tadalafil) for men who don’t respond to them. A more defensible reading of the evidence:

• HSDD in Premenopausal Women (FDA-approved indication): Significantly increased sexual desire and significantly reduced desire-related distress compared with placebo across two pivotal Phase 3 trials (N=1,267) [4].

• Erectile Dysfunction (off-label, research-supported): Statistically significant erectile response in men with mild-to-moderate ED in Phase 2 trials, including men unresponsive to sildenafil — because PT-141 acts on central arousal pathways rather than peripheral vasculature [1][2].

• Female Sexual Arousal Disorder (FSAD): Phase 2 crossover trial demonstrated significantly greater self-reported arousal and desire versus placebo in premenopausal women with FSAD and/or HSDD, establishing the basis for later Phase 3 development [3].

• General “libido enhancement” (marketing claim): Common clinic framing is broader than the approved indication. Evidence for men’s ED is real but off-label; use outside HSDD is not part of the Vyleesi label and carries the same side-effect profile.

Mechanism of Action

1. Non-selective Melanocortin Receptor Agonist: PT-141 binds several melanocortin receptor subtypes, but its pro-sexual effects are primarily mediated by high-affinity activation of the Melanocortin 4 Receptor (MC4R) in the hypothalamus [2].
2. Central Dopaminergic Signaling: MC4R activation in the paraventricular nucleus stimulates dopaminergic and pro-erectile nerve signaling, triggering sexual desire in women and initiating erections in men independently of local vascular dilation [1][3].
3. Contrast with PDE5 Inhibitors: Sildenafil and tadalafil work downstream, preserving local nitric-oxide-mediated vasodilation in the genitals. PT-141 works upstream in the brain, which is why it can be effective in men who don’t respond to PDE5 inhibitors.

Dosing Schedule

• Route: Subcutaneous (SC) injection — abdomen or thigh. This is the only FDA-approved route [4].

• FDA Approved Dose (HSDD): 1.75 mg SC as-needed, 45+ minutes pre-activity [4].

• Compounded / Clinic Pattern: Wellness clinics commonly prescribe 1.5–2 mg SC as-needed for both men and women (off-label use). Not evidence of longevity or performance benefit; the dosing mirrors the approved HSDD protocol.

• Maximum Frequency: 1 dose per 24 hours, 8 doses per month (per Vyleesi prescribing information) [4].

• Intranasal Spray: Not FDA-approved. Development halted by the FDA in 2007 due to unacceptable increases in blood pressure [1].

Clinical Trials

Bremelanotide has a complete clinical development record spanning early Phase 1 safety work through the pivotal Phase 3 RECONNECT program, which led to FDA approval in 2019.

Safety & Regulatory Notes

Research-Chemical Vendor Directory

Pricing collected February 2026. Standard presentation: 10 mg lyophilized powder, reconstituted for SC injection. Sorted by $/mg ascending.

Simple mean across 5 vendor listings: $5.90/mg. Cayman Chemical is a research-reagent supplier (not a typical clinic supply channel) and skews the mean upward.

References

1. [1]

   Diamond LE, et al. “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. pubmed.ncbi.nlm.nih.gov/15286159

2. [2]

   Edelson J, et al. “Bremelanotide: an intravenous, placebo-controlled, dose-escalation study to assess safety, tolerability, and pharmacodynamics in normal male subjects.” J Sex Med. 2006. pubmed.ncbi.nlm.nih.gov/16490022

3. [3]

   Safarinejad MR. “Evaluation of the safety and efficacy of PT-141, a melanocortin receptor agonist, in the treatment of female sexual arousal disorder and hypoactive sexual desire disorder: a double-blind, placebo-controlled, cross-over trial.” J Sex Med. 2008. pubmed.ncbi.nlm.nih.gov/18221285

4. [4]

   Kingsberg SA, et al. “Efficacy and Safety of Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Clinical Trials (The RECONNECT Trials).” Obstet Gynecol. 2019. pubmed.ncbi.nlm.nih.gov/31599840

5. [5]

   Peptide Sciences webpage. “PT-141 10mg.” peptidesciences.com/pt-141-10mg (accessed Feb 27, 2026)

6. [6]

   Limitless Life Nootropics webpage. “PT-141.” limitlesslifenootropics.com/product/pt-141 (accessed Feb 27, 2026)

7. [7]

   Core Peptides webpage. “PT-141 10mg.” corepeptides.com/peptides/pt-141-10mg (accessed Feb 27, 2026)

8. [8]

   SwissChems webpage. “PT-141 10mg.” swisschems.is/product/pt-141-10mg (accessed Feb 27, 2026)

9. [9]

   Cayman Chemical webpage. “Bremelanotide (acetate).” caymanchem.com/product/26197 (accessed Feb 27, 2026)