DOSING IN RESEARCH CONTEXT · NOT A RECOMMENDATION
PT-141 dosage: what the label and the trials documented
The approved label figures, the doses studied, and the pharmacokinetics — reported as record, never as a recommendation.
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This page documents PT-141 dosage as it appears in the approved label and the published trials. It does not recommend a dose for anyone. The numbers below describe what was given to study participants, by what route, and how the drug behaves in the body — context, not instruction.
The one approved dose exists in a specific setting: 1.75 mg, injected under the skin, taken as needed for HSDD in premenopausal women, with strict limits — no more than one dose in 24 hours and no more than eight a month [7]. Outside that exact setting, there is no established dose, because there is no approval. Material sold as a "research chemical" has no verified strength or purity, so any dose figure attached to it is doubly unreliable [7]. We report the documented figures; we draw no personal conclusions from them.
PT-141 dosage — the approved label figures
The US prescribing information for bremelanotide injection specifies a 1.75 mg subcutaneous dose, taken as needed at least 45 minutes before anticipated activity, with a hard ceiling of one dose per 24 hours and no more than eight doses per month [7]. The label warns of a transient blood-pressure increase and contraindicates use in uncontrolled high blood pressure or known cardiovascular disease [7].
These are labeled figures for the approved indication, quoted as documentation. They are not a protocol for any individual, and they do not transfer to off-label settings — male use, postmenopausal use, or "research chemical" material — where no equivalent evidence base exists.
PT-141 dosage for women — what the trials used
In the program that supported approval, premenopausal women with HSDD received 1.75 mg subcutaneously, as needed [3][7]. Earlier Phase 2 dose-finding in women tested 0.75, 1.25, and 1.75 mg subcutaneously before 1.75 mg was carried forward [7]. PT-141 dosage for women, as a documented research figure, refers to those trial doses — not to a number anyone should self-select. The trials enrolled premenopausal women specifically, so even within women the evidence does not extend to the postmenopausal setting [3].
Routes, pharmacokinetics, and stability
PT-141 has been studied by several routes: subcutaneous (the approved route), intranasal (early development, later discontinued for variable pharmacokinetics), and intravenous (early pharmacology) [7]. Early intranasal research in men used dose-escalation to roughly 7–20 mg, with a statistically significant erectile response above 7 mg [1].
Pharmacokinetically, the label reports a terminal half-life of about 2.7 hours (range 1.9–4.0 h), a volume of distribution near 25.0 L, clearance around 6.5 L/hr, roughly 21% protein binding, and excretion that is 64.8% renal and 22.8% fecal [7]. The cyclic lactam structure gives it more stability than linear melanocortin peptides [1].
How long does PT-141 last
On the question of how long does PT-141 last, two different clocks matter. The pharmacokinetic clock is short: a terminal half-life of about 2.7 hours after subcutaneous dosing means the drug clears the body within hours [7]. The functional clock can be longer: the human fMRI study found MC4R agonism raised sexual desire for up to 24 hours, well beyond the time the drug itself remains in circulation [5]. That gap — short drug half-life, longer behavioral effect — is itself a clue that the action is central and downstream, not a simple matter of drug concentration.