FAQ // STRAIGHT ANSWERS
PT-141 questions, answered straight
Definitions, mechanism, timing, and the doses from the research — answered plainly and cited where there's a number to cite.
What is PT-141?
PT-141 is the research designation for bremelanotide, a synthetic cyclic heptapeptide analogue of alpha-MSH that activates central melanocortin MC3R/MC4R receptors involved in sexual desire [1]. It's the molecule behind the FDA-approved HSDD drug for premenopausal women.
What is PT-141 peptide?
A 7-amino-acid cyclic lactam peptide (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH) that acts on melanocortin receptors in the brain rather than on blood vessels [6]. The ring structure gives it more stability than a straight-chain peptide.
What does the PT-141 peptide do?
By activating MC4R (and MC3R) in hypothalamic and limbic circuits, it's thought to engage dopaminergic pathways governing sexual desire and arousal [1][5]. It's the basis of the FDA-approved HSDD drug bremelanotide.
What is PT-141 used for?
Its single FDA-approved use is acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women [6]. Use in men, for erectile dysfunction, in postmenopausal women, or for sexual "performance" is off-label and not supported by the approval.
Is PT-141 the same as bremelanotide?
Yes. "Bremelanotide" is the international nonproprietary name (INN) for the compound; "PT-141" is the original research/development designation for the same molecule. When you read about one, you're reading about the other.
What is bremelanotide?
Bremelanotide is the FDA-approved (NDA 210557, June 2019) melanocortin receptor agonist for HSDD in premenopausal women, given as a 1.75 mg subcutaneous injection as needed [6]. PT-141 is its development code.
How does PT-141 work?
It activates central melanocortin receptors (chiefly MC4R) in the hypothalamus and limbic system, engaging dopaminergic circuitry of sexual motivation [1]. Unlike PDE-5 inhibitors, it acts centrally on desire rather than peripherally on blood flow [5].
What receptors does PT-141 act on?
Primarily the melanocortin 4 receptor (MC4R) and secondarily the melanocortin 3 receptor (MC3R), both concentrated in central nervous system circuits [1]. Peripheral MC1R activation underlies the hyperpigmentation seen with repeated dosing [6].
Does PT-141 work through the brain or through blood flow?
Through the brain. It's a central melanocortin agonist; an fMRI study in women with HSDD showed altered brain processing of erotic stimuli, distinguishing it mechanistically from peripheral, vascular PDE-5 inhibitors [5].
What is the PT-141 dosage?
The approved bremelanotide regimen is 1.75 mg subcutaneously as needed, at least 45 minutes before anticipated activity, with no more than one dose per 24 hours and no more than 8 per month [6]. Reported here as the label finding, not a protocol to follow.
How much PT-141 should I take?
No dose is recommended for any reader. The literature reports the approved 1.75 mg subcutaneous as-needed dose in premenopausal women with HSDD and various research doses (Phase 2 dose-finding at 0.75/1.25/1.75 mg) [6][8]. Material sold as "research chemical" is not the approved drug.
How much PT-141 to inject?
The studied subcutaneous dose in the approved population was 1.75 mg as needed [6]; early intranasal research in men used much higher milligram amounts (above a 7 mg threshold for an erectile response) [7]. These are findings, not dosing instructions.
What is the PT-141 dosage for women?
In the RECONNECT Phase 3 trials and the US label, premenopausal women with HSDD self-administered 1.75 mg subcutaneously as needed, capped at one dose per 24 hours and 8 per month [3][6].
How do you reconstitute PT-141?
The approved product is a prefilled 1.75 mg/0.3 mL subcutaneous autoinjector, not a powder requiring reconstitution [6]. "Research chemical" lyophilized powder is non-approved, laboratory-only material, and no preparation protocol is provided here.
How do you take PT-141?
The approved route is a single subcutaneous injection into the abdomen or thigh, as needed before anticipated activity [6]. Described as the label finding, not as advice to self-administer.
How often can you take PT-141?
The label specifies no more than one dose per 24 hours and no more than 8 doses per month [6]. High-frequency dosing was used only in dedicated Phase 1 obesity research protocols [6].
What is the approved bremelanotide dose?
1.75 mg subcutaneous, as needed, at least 45 minutes before anticipated sexual activity, capped at one dose/24 h and 8 doses/month per the US prescribing information [6].
How long does PT-141 last?
The label notes a terminal half-life of about 2.7 hours (range 1.9–4.0 h) after subcutaneous dosing [6]; subjective effects are reported over a window of hours, with some women in the fMRI study showing increased desire for up to 24 hours [5].
How long does PT-141 take to work?
Median Tmax after subcutaneous injection is roughly 0.5–1.0 hour; the label directs dosing at least 45 minutes before anticipated activity [6]. Early intranasal research reported onset of a first erection in men at about 30 minutes [7].
What is the half-life of PT-141?
Approximately 2.7 hours (range 1.9–4.0 h) by the subcutaneous route per the US label [6]; early intranasal studies reported 1.85–2.09 hours [7].
How long does PT-141 stay in your system?
With a ~2.7-hour terminal half-life, the drug is largely cleared within a day [6]. It's metabolized by hydrolysis of the cyclic-peptide bonds and excreted 64.8% renally and 22.8% fecally in a radiolabeled study [6].
Does PT-141 nasal spray work?
An intranasal formulation was studied early (a statistically significant erectile response in men appeared above 7 mg, and a 20 mg intranasal dose increased sexual desire in women with arousal disorder), but intranasal development was discontinued over pharmacokinetic variability; the approved product is subcutaneous [7].