# PT-141 Dosage Research: The Label Dose, PK & Routes Studied

> PT-141 (bremelanotide) dosage from the record: the 1.75 mg approved label dose, ~2.7 h half-life, routes studied, and pharmacokinetics. Study-attributed; no personal dose is recommended.

Approved label dose: 1.75 mg subcutaneous, as needed. Terminal half-life ~2.7 h. Read as documented research, not as a recommendation.

## The short version

PT-141 dosage figures come from the FDA label and clinical-trial protocols. The approved dose is 1.75 mg given as a subcutaneous injection (under the skin), taken as needed at least 45 minutes before anticipated sexual activity, no more than once in 24 hours and no more than 8 times a month [7]. That is the labeled regimen for the one approved use; it is not a recommendation for any individual.

The peptide clears fast. Its terminal half-life — the time for the blood level to fall by half — is about 2.7 hours [7]. This page lists the doses and routes that were *studied*, the pharmacokinetics (how the body absorbs and clears it), and the half-life. No dose is recommended for anyone here, and the research-chemical form is not the approved drug.

## PT-141 dosage — the approved label

The US prescribing information specifies the regimen precisely. Indication: acquired, generalized HSDD in premenopausal women. Dose: 1.75 mg subcutaneous, as needed, at least 45 minutes before anticipated activity; maximum one dose per 24 hours and no more than 8 doses per month [7]. The label warns of a transient blood-pressure increase and contraindicates uncontrolled hypertension or known cardiovascular disease [7].

This is documented as a labeled dose, not as guidance. Earlier Phase 2 dose-finding in women evaluated 0.75, 1.25, and 1.75 mg subcutaneous before 1.75 mg was selected [3]. Doses studied in other contexts — early intranasal dose-escalation in men (~7-20 mg) and a Phase 1 obesity research protocol (up to 2.5 mg, up to three times daily for 15 days) — were research protocols only, not approved use [13].

## How long does PT-141 last

The pharmacokinetics are well characterized in the label. Terminal half-life is approximately 2.7 hours (range 1.9-4.0 h) after subcutaneous dosing; early intranasal studies reported 1.85-2.09 h [7][13]. Median time to peak concentration (Tmax) is ~0.5-1.0 hour after subcutaneous injection [7].

Distribution and clearance: volume of distribution ~25.0 L, clearance ~6.5 L/hr, serum protein binding ~21%. The peptide is metabolized by hydrolysis of its cyclic-peptide amide bonds and peptidase digestion, and excreted 64.8% renally and 22.8% fecally [7]. The desire effect in the imaging study, by contrast, persisted up to 24 hours — longer than the plasma half-life, consistent with a central, downstream action that outlasts the circulating peptide [5].

## PT-141 dosage for women

For the one approved use, PT-141 dosage for women is the 1.75 mg subcutaneous as-needed regimen above [7]. The preclinical basis: in female rats, PT-141 selectively stimulated appetitive solicitational sexual behaviors without affecting lordosis, pacing, or general motor activity — evidence that central melanocortin systems regulate female sexual desire [2].

The Phase 3 trials that supported the label dosed 1,267 premenopausal women at 1.75 mg as needed over 24 weeks, meeting both coprimary desire and distress endpoints [3], with a 52-week extension confirming sustained effect [4]. These figures describe what was administered in the trials and on the label — not a recommendation for any reader. Use in postmenopausal women is not an approved indication.

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A two-ink lab-notebook digest of the PT-141 (bremelanotide) record — the central MC4R mechanism, the premenopausal-HSDD-only approval, and the nausea-led tolerability cost logged to source and overprinted in plain sight, with the research-chemical form kept clearly off-register from the approved drug; no clinic behind the press and nothing here dosed, dispensed, or sold.