# PT-141 Dosage and Half-Life in the Research and Label Record

> PT-141 (bremelanotide) dosage as reported in the trials and FDA label: the approved 1.75 mg subcutaneous regimen, Phase 2 dose-finding, and a ~2.7 h half-life — findings only, no protocol.

The approved subcutaneous regimen, the Phase 2 dose-finding doses, and the pharmacokinetics — reported strictly as study and label findings, never as instructions to follow.

## The short version

This page reports the doses PT-141 (bremelanotide) was studied and approved at — as facts from the trials and the FDA label, not as a plan for anyone to follow. For the approved use (HSDD in premenopausal women), the label specifies a single 1.75 mg shot under the skin, taken as needed, with hard limits: no more than one dose in 24 hours and no more than eight a month [7]. It clears the body fairly quickly — a half-life of roughly 2.7 hours [7]. Any legitimate use of the approved drug happens under a licensed clinician; this site recommends no dose and sells nothing.

## PT-141 dosage in the research literature

PT-141 dosage in the research literature is anchored by the approved label and the trial protocols. Per the U.S. prescribing information, the approved regimen for HSDD in premenopausal women is 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 [7]. That 1.75 mg figure was selected through Phase 2 subcutaneous dose-finding in women, which compared 0.75, 1.25, and 1.75 mg [3]. Other doses appear only in early or investigational research: dose-escalation intranasal studies in men with erectile dysfunction reached roughly 7–20 mg, and a Phase 1 obesity protocol in women administered up to 2.5 mg as often as three times daily for 15 days [1]. These are documented research doses, reported as findings; none is a recommendation, and the higher-frequency protocols carry the tolerability and pigmentation considerations covered on the [PT-141 side effects](/side-effects) page.

## How the label dosing works, step by step

The approved regimen is built around an as-needed, tightly-capped schedule. Presented as the label's stated structure — a finding, not an instruction:

1. **As-needed, before activity.** The 1.75 mg subcutaneous dose is taken on demand, at least 45 minutes before anticipated sexual activity, rather than on a daily schedule [7].
2. **Strict frequency limits.** No more than one dose per 24 hours, and no more than eight doses per month [7]. These caps are part of the approval, not optional guidance.
3. **Clinician supervision and screening.** Because of a documented transient blood-pressure increase, the label contraindicates use in uncontrolled hypertension or known cardiovascular disease — making clinical screening part of the regimen [7].
4. **Stop rules for tolerability.** Nausea is common and was the leading reason participants discontinued in long-term use, so persistence is assessed against tolerability over time [4].

## Pharmacokinetics: clearance, distribution, and excretion

The U.S. prescribing information characterizes the pharmacokinetics of subcutaneous bremelanotide in detail [7]. Median time to peak concentration (Tmax) is roughly 0.5–1.0 hours after injection. The volume of distribution is about 25.0 L and clearance about 6.5 L/hr, with approximately 21% serum protein binding. The drug is metabolized by hydrolysis of the cyclic-peptide amide bonds and by peptidase digestion, and a radiolabeled dose was excreted 64.8% renally and 22.8% fecally [7]. The cyclic lactam structure confers greater stability than linear melanocortin peptides, which is part of why a single subcutaneous dose behaves predictably [1]. The NIH LiverTox monograph notes the drug is associated with mild serum-enzyme elevations and rare clinically apparent liver injury, with minimal drug-drug interactions owing to its peptidase-based metabolism [10].

### How long does PT-141 last?

Pharmacokinetically, PT-141 clears fairly quickly: the U.S. label reports a terminal half-life of approximately 2.7 hours (range 1.9–4.0 h) after subcutaneous dosing, with peak levels reached within about an hour [7]. Note that pharmacokinetic duration is not the same as duration of the desire effect — the 2022 fMRI study reported increased desire for up to 24 hours after dosing [5].

### PT-141 half-life

The PT-141 half-life is approximately 2.7 hours (range 1.9–4.0 h) by the terminal phase after subcutaneous administration, per the U.S. prescribing information [7]. Early intranasal studies, by a different route, reported a shorter 1.85–2.09 h [1]. Half-life is a pharmacokinetic property reported here as a finding.

### What is the approved bremelanotide dose?

Per the U.S. prescribing information, the approved bremelanotide dose is 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 [7]. Reported as a label finding only.

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A calm clinical-platform reading of the bremelanotide record, read in low light — the approved-for-premenopausal-HSDD-only scope surfaced first, the cited trial and label evidence flagged green, the unverified field reports fenced off amber; no clinic behind the platform and nothing here prescribed, dispensed, or sold.