FREQUENTLY ASKED · ANSWERED FROM THE RECORD
PT-141 FAQ
Direct answers to the most common PT-141 questions, each drawn from the cited literature and the FDA label — definitions, mechanism, the approved dosing, and duration.
What is PT-141?
PT-141 is the research designation for bremelanotide, a synthetic cyclic heptapeptide and melanocortin (MC3R/MC4R) receptor agonist that acts centrally — on the brain — to influence sexual desire and arousal [1]. It is FDA-approved as bremelanotide for one indication: HSDD in premenopausal women [7].
What is PT-141 peptide?
It is a seven-amino-acid peptide joined in a ring (a cyclic heptapeptide), built as a synthetic analogue of the natural hormone alpha-MSH [1][8]. The cyclic structure makes it more stable than linear melanocortin peptides [6]. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH [6].
What does the PT-141 peptide do?
It activates central melanocortin receptors — chiefly MC4R — in hypothalamic and limbic circuits linked to sexual motivation [1]. In the approved population, premenopausal women with HSDD, it improved sexual desire and reduced desire-related distress versus placebo in two Phase 3 trials [3].
What is PT-141 used for?
Bremelanotide is FDA-approved only for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women [7]. Every other use — in men, for erectile dysfunction, or in postmenopausal women — is off-label and investigational, supported only by early-phase evidence, not by the approval [1][9].
Is PT-141 the same as bremelanotide?
Yes. Bremelanotide is the international nonproprietary name (INN) for the compound; PT-141 is its research designation [7]. They are the same melanocortin receptor agonist, with the same structure and the same CAS number, 189691-06-3 [6].
What is bremelanotide?
Bremelanotide is the approved-drug name for PT-141, a melanocortin (MC3R/MC4R) receptor agonist approved in June 2019 (NDA 210557) for HSDD in premenopausal women, given as a 1.75 mg subcutaneous as-needed injection [6][7].
What are the benefits of PT-141?
In the Phase 3 RECONNECT trials it produced statistically significant but clinically modest gains in sexual desire (integrated FSFI-desire +0.35) and reductions in desire-related distress (FSDS-DAO item 13 -0.33) versus placebo [3]. Independent re-analyses argue these effects are small [10].
How does PT-141 work?
It stimulates central MC4R (and MC3R) receptors in hypothalamic circuits such as the medial preoptic area, engaging dopaminergic pathways of sexual motivation [1][3]. It acts on the brain's desire circuitry rather than on blood vessels [1].
What receptors does PT-141 act on?
Primarily the melanocortin 4 receptor (MC4R), with secondary activity at the melanocortin 3 receptor (MC3R) [1]. Both are central-nervous-system melanocortin receptor subtypes within the five-member MC1R-MC5R family [8].
Does PT-141 work through the brain or through blood flow?
Through the brain. Unlike PDE-5 inhibitors, which act peripherally on vascular smooth muscle, PT-141 works centrally on the neural circuitry of sexual desire and arousal [1]. Human fMRI data showed it changing how the brain processes sexual stimuli [5].
What is a melanocortin receptor agonist?
A molecule that activates melanocortin receptors (MC1R-MC5R), a family of G-protein-coupled receptors responsive to peptides like alpha-MSH [8]. PT-141 targets the central MC3R and MC4R subtypes [1].
Does PT-141 increase testosterone?
No. PT-141 does not act through the HPG (hypothalamic-pituitary-gonadal) axis and does not directly raise testosterone; it modulates sexual desire centrally via melanocortin signaling [1]. This is one of the most common misconceptions about the compound.
How is PT-141 different from PDE-5 inhibitors?
PDE-5 inhibitors (such as sildenafil and tadalafil) act peripherally on vascular smooth muscle to support erectile blood flow; PT-141 acts centrally on the melanocortin circuits governing sexual desire — a fundamentally different mechanism [1].
What is the PT-141 dosage?
The approved label for the HSDD indication specifies 1.75 mg subcutaneously, as needed, with no more than one dose per 24 hours and no more than 8 doses per month [6]. Reported here as a label finding, not a protocol to follow.
How much PT-141 should I take?
This site reports trial and label doses only as findings and recommends no dose for any individual. The approved regimen for HSDD in premenopausal women was 1.75 mg subcutaneous as-needed [6]. Any use decision belongs with a qualified clinician, not this page.
How much PT-141 to inject?
In the Phase 3 trials and the label the subcutaneous dose was 1.75 mg as needed [3][6]; Phase 2 dose-finding studied 0.75, 1.25, and 1.75 mg [3]. Reported as findings only — this is not an instruction to inject any amount.
How do you reconstitute PT-141?
The approved finished drug is a ready-to-use single-dose subcutaneous injection, not a reconstituted powder [6]. Material sold as "PT-141 research chemical" is a laboratory reagent and is not the approved product; no human-use mixing instructions are given here [6].
How do you take PT-141?
The approved route is subcutaneous injection, self-administered at least 45 minutes before anticipated activity per the label [6]. Earlier intranasal development was discontinued because of pharmacokinetic variability [6]. Reported as a label finding only.
How often can you take PT-141?
The label limits dosing to no more than one dose per 24 hours and no more than 8 doses per month [6]. Reported as a label finding, not as guidance for use by any individual.
What is the approved bremelanotide dose?
1.75 mg subcutaneously, as needed, for HSDD in premenopausal women, with a maximum of one dose per 24 hours and 8 doses per month, per the US prescribing information [6].
What is the PT-141 dosage for women?
For the approved HSDD indication in premenopausal women, the label dose was 1.75 mg subcutaneously, as needed, at least 45 minutes before anticipated activity, with no more than one dose per 24 hours and 8 doses per month [6]. A label finding, not a protocol.
How long does PT-141 last?
Its terminal half-life is approximately 2.7 hours (range 1.9-4.0 h) by the subcutaneous route per the label, with median Tmax around 0.5-1.0 hours [6]; the mechanistic fMRI study reported increased sexual desire for up to 24 hours [5].