Label & pharmacokinetics · Reported figures
PT-141 Dosage: The Label Figure and the Pharmacokinetics
What the approved label and the trials report — the 1.75 mg subcutaneous as-needed figure, the per-24-hour and monthly limits, and the half-life — stated as findings, never as a protocol for any reader.
Before the figures
This page reports the PT-141 dosage the way the FDA label and the trials state it — as documented figures, not as instructions for anyone. The approved drug is given as a 1.75 mg shot under the skin, taken only when needed, with hard limits on how often. It clears the body fairly quickly (a half-life of a few hours), which shapes those limits. The 'research chemical' powder sold online is a different, unregulated material, and this digest gives no preparation or self-dosing guidance. Dosing decisions belong with a qualified clinician. Everything below is reference, not advice.
The approved label dose
The US prescribing information specifies a PT-141 dosage of 1.75 mg administered 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]. The approved product is a prefilled subcutaneous autoinjector, not a reconstituted powder [6]. These figures are the approved-label record for the HSDD indication in premenopausal women; they are reported here as the label specifies them, not as a protocol any reader should follow.
The per-24-hour limit is not arbitrary. It is partly informed by the transient blood-pressure increase the drug produces, which is also why the label contraindicates use in uncontrolled hypertension or known cardiovascular disease [6]. See tolerability and adverse events for that safety boundary in full.
PT-141 Dosage for Women in the Approved Label
For the approved HSDD indication in premenopausal women, the label dosage is 1.75 mg subcutaneous as-needed, subject to the same maximums: no more than one dose in 24 hours and no more than 8 doses per month [6]. This is the only population for which a dose is FDA-approved. The figure is reported as the label value; it is not a recommendation, and use in any other population is off-label and outside the approval [6].
Doses studied across development
Development studied a range of doses by route, all reported here as research figures. Phase 2 subcutaneous dose-finding in women evaluated 0.75, 1.25, and 1.75 mg before the 1.75 mg dose was carried into Phase 3 [3]. Early intranasal research in men with erectile dysfunction escalated to roughly 7-20 mg, with a statistically significant erectile response above about 7 mg, but the intranasal route was discontinued for pharmacokinetic variability. Phase 1 obesity research in women used subcutaneous doses up to 2.5 mg, up to three times daily for 15 days — a high-frequency research protocol only, never an approved regimen [10]. None of these are dosing instructions.
PT-141 Half-Life
The PT-141 half-life is short. After subcutaneous administration, the terminal half-life is approximately 2.7 hours, with a range of 1.9-4.0 hours reported in the US prescribing information; early intranasal studies reported 1.85-2.09 hours [6]. Median Tmax (time to peak concentration) is roughly 0.5-1.0 hour after subcutaneous injection [6]. The short half-life is consistent with the drug's as-needed, per-event use rather than daily dosing.
How Long Does PT-141 Last?
How long PT-141 lasts depends on whether you mean the drug in the blood or the measured effect. Pharmacokinetically the molecule clears quickly — terminal half-life about 2.7 hours [6]. The desire effect, however, outlasts the plasma window: the fMRI study found MC4R agonism increased self-reported sexual desire for up to 24 hours [5]. The compound is gone from circulation long before the measured desire signal fades.
Pharmacokinetics and clearance
The remaining pharmacokinetics, all from the prescribing information, are reported as label figures [6]. Volume of distribution is about 25.0 L and clearance about 6.5 L/hr; serum protein binding is roughly 21% [6]. The peptide is metabolized by hydrolysis of its cyclic amide bonds and peptidase digestion, and a radiolabeled dose was excreted 64.8% renally and 22.8% fecally [6]. The cyclic lactam structure confers greater stability than linear melanocortin peptides, which is the structural reason the molecule survives long enough to act [6].