DOSAGE / PHARMACOKINETICS
PT-141 dosage, half-life, and pharmacokinetics — read as label and trial findings.
The approved label specifies 1.75 mg subcutaneous, as needed. The terminal half-life is about 2.7 hours. Every figure here is reported as a study or label finding — never as a protocol for any individual.
Before the details
This page reports the PT-141 dosage and pharmacokinetics (how the body absorbs and clears the drug) exactly as the trials and the FDA label describe them — and only that way. It does not recommend a dose for anyone. The approved drug, bremelanotide, is given as a 1.75 mg injection just under the skin, used as needed before anticipated activity, with strict limits: no more than one dose in 24 hours and no more than 8 a month. It clears the body fairly quickly — a half-life (the time for half the drug to leave) of about 2.7 hours. Whether and how a drug applies to a person is a clinician's decision, not something a website should script.
PT-141 Dosage for Women in the Approved Label
For the approved HSDD indication in premenopausal women, the US prescribing information specifies bremelanotide 1.75 mg subcutaneously, as needed, at least 45 minutes before anticipated sexual activity, with no more than one dose per 24 hours and no more than 8 doses per month [6].
That dose was selected from Phase 2 subcutaneous dose-finding in women, which evaluated 0.75, 1.25, and 1.75 mg [11]. The 1.75 mg as-needed regimen is what RECONNECT tested and what the label carries [3][6]. Reported here strictly as the label finding — this is the documented approved regimen for one population, not a protocol for any reader, and the dosing ceiling is tied in part to the cardiovascular profile covered on the side-effects page [6].
Half-Life and Pharmacokinetics of PT-141
After subcutaneous administration, bremelanotide has a terminal half-life of approximately 2.7 hours (range 1.9-4.0 h) per the US prescribing information [6]. Early intranasal studies in men reported a shorter half-life of 1.85-2.09 hours for that route [7].
The broader pharmacokinetic profile from the label: volume of distribution ~25.0 L; clearance ~6.5 L/hr; about 21% serum protein binding; metabolism by hydrolysis of the cyclic-peptide amide bonds and peptidase digestion; and excretion split 64.8% renal and 22.8% fecal of a radiolabeled dose [6]. The cyclic lactam ring confers greater stability than linear melanocortin peptides — the structural feature that made the molecule a viable drug [6].
How Long Does PT-141 Last?
Pharmacokinetically, PT-141 acts and clears on a short timeline. Median Tmax — time to peak concentration — is about 0.5 to 1.0 hours after subcutaneous injection [6], which is why the label specifies dosing at least 45 minutes before anticipated activity [6].
With a terminal half-life near 2.7 hours, the bulk of the compound is cleared within a workday [6]. The behavioral effect, however, can outlast the drug in plasma: the 2022 fMRI study found that MC4R agonism increased sexual desire for up to 24 hours — desire and drug concentration are not the same clock [5]. The as-needed, episodic design follows directly from this short pharmacokinetic window [6].
Routes studied and the research-dose context
Three routes appear in the literature: subcutaneous (the approved route), intranasal (early development, discontinued for PK variability), and intravenous (early pharmacology) [6][7][8].
Doses across the research record, reported as findings: the approved 1.75 mg SC as-needed (women, HSDD) [6]; Phase 2 SC dose-finding at 0.75 / 1.25 / 1.75 mg (women) [11]; early intranasal dose-escalation in men to roughly 7-20 mg, with a statistically significant erectile response above 7 mg [7]; and a Phase 1 obesity research protocol in women using subcutaneous doses up to 2.5 mg, up to three times daily for 15 days — a research protocol only, and a reminder that high-frequency dosing engages the MC4R appetite pathway [11]. None of these are instructions; they are the documented doses studied. The male-route research is detailed on PT-141 for men (off-label research).
How is PT-141 supplied, and the reconstitution question
The approved bremelanotide product is a ready-to-use prefilled subcutaneous autoinjector — not a powder that a patient reconstitutes [6]. Reconstitution questions arise around the unapproved "research chemical" lyophilized (freeze-dried) form, which is laboratory material only and is not the finished drug product [11].
This site describes the literature and the label, not preparation steps. The distinction matters: the approved finished drug and laboratory "PT-141" are not interchangeable, and material sold as a research chemical carries no regulatory assurance of identity, purity, or concentration [11].