# PT-141 Dosage, Half-Life, and Duration: The Label and the Research > PT-141 dosage as documented in the approved label and trials — 1.75 mg subcutaneous as-needed, ~2.7 h half-life, frequency limits, and the dose-finding history. Reported as findings, never as a protocol. What the approved label and the trials specify — the 1.75 mg subcutaneous as-needed dose, the ~2.7 h half-life, and the frequency caps. Reported as documented findings, not as guidance. ## The short version This page reports the PT-141 dosage figures from the approved label and the trials — and only as findings, never as a protocol for anyone to follow. In the one approved use, bremelanotide is `1.75 mg` injected just under the skin (subcutaneous), taken as needed before anticipated activity, with hard limits: no more than one dose per 24 hours and no more than eight per month. It clears the body fairly quickly — a terminal half-life (the time for the blood level to fall by half late in the curve) of about 2.7 hours. The dose-finding history and the duration details follow. ## PT-141 Dosage in the Research and the Approved Label The approved **PT-141 dosage** is documented precisely in the US prescribing information: 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 eight doses per month [5]. This is reported here as a label finding — the figure the FDA approved for the HSDD indication — not as a recommendation for any individual. The dose was not arbitrary. A randomized, placebo-controlled subcutaneous dose-finding trial evaluated `0.75`, `1.25`, and `1.75 mg` in premenopausal women with female sexual dysfunction, and `1.75 mg` was the dose advanced to Phase 3 [8]. Phase 2b responder analyses examined the proportion of women reaching clinically meaningful improvement across doses, supporting the benefit-risk basis for that selection [9]. Early intranasal research in men (a discontinued route) escalated to roughly 7-20 mg, with a statistically significant erectile response above 7 mg — investigational, off-label history, not a guide [1]. ## PT-141 Dosage for Women: the Approved 1.75 mg Regimen The approved population is the only one with a labeled regimen. The **PT-141 dosage for women** with acquired, generalized HSDD — and only premenopausal women — is `1.75 mg` subcutaneous as-needed, capped at one dose per 24 hours and eight per month [5][6]. The product is supplied as a ready-to-use subcutaneous autoinjector, not a powder requiring reconstitution [5]. This regimen is what the RECONNECT Phase 3 program tested (`n=1267`) and what the 52-week extension carried to a year [3][4]. It is documented as the approved finding for this specific population; it is not a dose for men, for postmenopausal women, or for any off-label purpose, and it is not guidance for a reader. ## How Long Does PT-141 Last? Half-Life and Duration **How long does PT-141 last?** Pharmacokinetically, the terminal half-life after subcutaneous administration is approximately `2.7 hours` (range `1.9-4.0 h`) per the US prescribing information [5]. Median Tmax — the time to peak concentration — is roughly `0.5-1.0 h` after a subcutaneous injection [5]. Early intranasal studies reported a shorter half-life of `1.85-2.09 h` [5]. The subjective duration is a different measurement than the blood-level half-life: the 2022 fMRI study found MC4R agonism increased sexual desire for up to 24 hours, a central effect that outlasts the drug's plasma presence [13]. Supporting pharmacokinetics from the label: volume of distribution `~25.0 L`, clearance `~6.5 L/hr`, serum protein binding `~21%`, and excretion `64.8%` renal / `22.8%` fecal from a radiolabeled dose [5]. The cyclic lactam structure gives it greater stability than linear melanocortin peptides [6]. ## PT-141 Half-Life To state the **PT-141 half life** on its own: approximately `2.7 hours` (range `1.9-4.0 h`) terminal half-life after subcutaneous dosing, per the prescribing information [5]. That is a short half-life for a peptide drug — consistent with its as-needed, before-activity dosing rather than a daily standing dose. The metabolism is by hydrolysis of the cyclic-peptide amide bonds and peptidase digestion [5]. See the full [PT-141 dosage and half-life](/dosage) figures above; all are reported as label findings. ## Routes studied Three routes appear in the development record [5]. Subcutaneous is the approved route and the one carried through Phase 3 [3][5]. Intranasal was used in early development — including the male ED dose-escalation and the 2006 female arousal study [1][7] — but was discontinued due to pharmacokinetic variability [5]. Intravenous appeared in early pharmacology [5]. A Phase 1 obesity research protocol used subcutaneous dosing up to `2.5 mg`, up to three times daily for 15 days — a research protocol only, well outside the approved as-needed regimen and named here strictly as documented history [5]. --- A documentation-grade reading of the bremelanotide record — the approved label and the Phase 3 endpoints logged to source, the effect-size debate left in plain view, and the field reports fenced off from the evidence; not a clinic, not a vendor, not a prescription.