The dosing literature
PT-141 Dosage: What the Trials and the Label Document
The doses that were studied, the dose that was approved, and the pharmacokinetics — reported as published figures, with no recommendation for any person.
Read this first
This page reports the PT-141 dosage figures that appear in the published trials and the prescribing information — and nothing here is a recommendation for any individual. The one approved figure is precise: for premenopausal women with HSDD, the label specifies 1.75 mg subcutaneously (under the skin), as needed, no more than one dose in 24 hours and no more than eight doses per month [7]. Across development, the studied doses ranged wider — Phase 2 dose-finding used 0.75, 1.25, and 1.75 mg in women; early intranasal work in men escalated much higher [7]. We report these as what was administered, to whom, by which route. The pharmacokinetics — how fast it clears — are documented too. None of it tells any reader what to do; it tells you what the studies measured.
PT-141 dosage
The approved PT-141 dosage is documented, not improvised: 1.75 mg subcutaneous, as needed, taken at least 45 minutes before anticipated activity, capped at one dose per 24 hours and eight doses per month [7]. That ceiling is itself a safety feature — it limits cumulative exposure and the frequency-dependent effects (pigmentation, blood-pressure rise) discussed on the effects page. Development used a tighter dose-finding window in women — 0.75, 1.25, and 1.75 mg subcutaneously — with 1.75 mg carried forward into the pivotal trials [7]. Reported as a labeled figure, this is the only dose with approval-grade evidence behind it; doses outside it, or in populations outside premenopausal HSDD, are investigational.
PT-141 dosage for women
PT-141 dosage for women is the best-evidenced part of the record, because the approval is specifically for premenopausal women with HSDD: 1.75 mg subcutaneous, as needed, within the monthly cap above [7]. The Phase 2 dose-finding that preceded approval tested 0.75, 1.25, and 1.75 mg in women before 1.75 mg was selected [7]. Preclinical female-rat work informs the rationale rather than the dose — it showed PT-141 selectively increased appetitive sexual solicitation without affecting motor activity, supporting a desire-specific central effect [2]. For postmenopausal women, the approved figure does not apply; use outside the premenopausal indication is off-label [7].
PT-141 injection and reconstitution
PT-141 injection is subcutaneous — the approved and best-studied route [7]. The route is not incidental: a beagle-dog PK study confirmed minimal oral absorption, which is why an oral form was not pursued and the drug is injected [10]. Early development also explored intranasal delivery (later discontinued for pharmacokinetic variability) and intravenous dosing for early pharmacology, so "injection" specifically means the subcutaneous route in the approved product [7]. Reconstitution is a procedural question about the unregulated research-chemical form, not the approved pharmaceutical, which ships ready to use; because the research-chemical form has no oversight of identity, purity, or concentration, this site does not provide reconstitution or preparation instructions [7].
How long does PT-141 last
How long PT-141 lasts has two answers — how long it stays in the blood, and how long its effect lasts. Pharmacokinetically, the prescribing information gives a terminal half-life of about 2.7 hours (range 1.9–4.0 h) after subcutaneous dosing, with median Tmax around 0.5–1.0 hour, a volume of distribution of ~25.0 L, clearance ~6.5 L/hr, and excretion split 64.8% renal and 22.8% fecal [7]. Early intranasal studies reported a similar half-life of 1.85–2.09 h [7]. The effect, though, outlasts the drug in plasma: the fMRI study measured increased desire for up to 24 hours after a single dose — consistent with a central mechanism whose downstream changes persist after the peptide itself has cleared [5]. So "lasts a few hours" is true of the molecule and understates the behavioral window.
Pharmacokinetics in one place
For readers who want the numbers together, the label documents: terminal half-life ~2.7 h (range 1.9–4.0 h); median Tmax ~0.5–1.0 h; volume of distribution ~25.0 L; clearance ~6.5 L/hr; ~21% serum protein binding; metabolism by hydrolysis of the cyclic-peptide bonds and peptidase digestion; and excretion 64.8% renal / 22.8% fecal from a radiolabeled dose [7]. The cyclic lactam structure is the reason the molecule is more stable than linear melanocortin peptides, though still short-lived enough to require as-needed rather than maintenance dosing [1][7]. Every figure here is a published label value, reported as such — not a dosing instruction.