# PT-141 Dosage: The Labeled Regimen and Pharmacokinetics — Bremelanotide

> PT-141 (bremelanotide) dosage as documented in the FDA label: 1.75 mg subcutaneous as-needed for approved HSDD, with half-life, Tmax, and PK figures. Research context only, no recommendation.

The approved regimen as written, the pharmacokinetics, and the routes that were studied — reported, never recommended.

## The gist

In plain words: for the one approved use, the PT-141 dosage on the FDA label is fixed and simple — 1.75 mg injected under the skin, taken only when needed, no more than once in 24 hours and no more than eight times a month [7]. It is not a daily medicine and not titrated up. The label exists only for the approved prescription product used in premenopausal women with distressing low desire; it does not authorize any use in men or anyone else. Because PT-141 is an FDA-approved drug, this page reports the labeled figures as labeled figures — it is not a recommendation, and it tells no one what to take. The research-chemical version sold separately has no verified strength at all, which is exactly why a label dose tells you nothing about what is in such a vial.

## PT-141 dosage

The approved PT-141 dosage, per the US prescribing information for bremelanotide injection, is 1.75 mg subcutaneously, as needed, at least 45 minutes before anticipated activity, with a ceiling of one dose per 24 hours and no more than eight doses per month [7]. The Phase 2 dose-finding program in women tested 0.75, 1.25, and 1.75 mg before the as-needed 1.75 mg dose was carried into the pivotal trials [3]. These are documented study and label doses, reproduced for reference; this site recommends no dose to any individual and gives no instruction on use.

## PT-141 injection

The approved PT-141 injection route is subcutaneous — under the skin — which is how the drug was given in RECONNECT and how the label specifies it [3][7]. Two other routes appear in the development history: intranasal delivery was studied early but discontinued because of pharmacokinetic variability, and intravenous administration was used in early pharmacology work [7]. The subcutaneous route is the only one that reached approval. Reconstitution and handling of any non-pharmaceutical material are outside the scope of this digest, which describes only what the published record and the label document.

## How long does PT-141 last

How long PT-141 lasts, pharmacokinetically, is well characterized for the approved product. The terminal half-life is approximately 2.7 hours, with a reported range of 1.9 to 4.0 hours after subcutaneous administration per the US prescribing information; early intranasal studies reported 1.85 to 2.09 hours [7]. Median time to peak concentration (Tmax) is roughly 0.5 to 1.0 hour after subcutaneous injection [7]. Separately, the mechanistic fMRI study found the desire effect on brain processing persisted for up to 24 hours — a duration of pharmacodynamic effect that outlasts the plasma half-life, because the receptor-triggered downstream effect is not the same as the drug staying in the blood [5].

## Pharmacokinetics readout

The remaining pharmacokinetic figures, all from the prescribing information: volume of distribution approximately 25.0 L; clearance approximately 6.5 L/hr; serum protein binding about 21%; metabolism by hydrolysis of the cyclic-peptide amide bonds and peptidase digestion; and excretion split 64.8% renal and 22.8% fecal of a radiolabeled dose [7]. The label also documents a transient post-dose increase in blood pressure, the basis for the contraindication in uncontrolled hypertension or cardiovascular disease [7]. The cyclic lactam structure underlies the molecule's relative metabolic stability compared with linear melanocortin peptides [1].

## PT-141 dosage for women

The PT-141 dosage for women is the only dosing context with a regulatory basis: the approved 1.75 mg subcutaneous as-needed regimen described above applies specifically to premenopausal women with acquired, generalized HSDD [7][9]. The preclinical groundwork is consistent with this female-desire focus — in female rats, PT-141 selectively increased appetitive solicitational sexual behavior, the desire-driven component, without altering reflexive behaviors or motor activity [2]. Beyond the approved premenopausal-HSDD population — including postmenopausal women — there is no approved dosing, and uses there are off-label. As everywhere on this site, these are documented study and label figures, not advice.

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A regulatory-careful console on the PT-141 (bremelanotide) record — the one approved use (premenopausal HSDD) held apart from the off-label edges and the no-oversight research-chemical form, every figure logged to the trials or the FDA label and nothing here prescribed, dispensed, or sold from behind the steel.