DOSE & TIMING ~ AS REPORTED
PT-141 dosage, half-life, and timing — reported as findings, not as a protocol.
What the approved label specifies, what the dose-finding trials tested, and how long the drug lasts. These are figures of record. They are not instructions for any reader to follow.
The short version
This page reports the PT-141 dosage figures that appear in the trials and on the approved label — and nothing here is a recommendation. In its approved use, the label specifies bremelanotide 1.75 mg injected under the skin (subcutaneous — just under the skin), taken only as needed, with hard limits: no more than one dose in 24 hours and no more than eight in a month [11]. The drug clears quickly: its half-life — the time for the amount in the blood to fall by half — is about 2.7 hours [11]. We state these as facts on record because people search for them; we do not tell anyone to use them.
PT-141 Dosage in the Research Literature
Reported strictly as findings: the approved label specifies bremelanotide 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 [11]. This is the figure of record for the approved premenopausal-HSDD indication — not a protocol for any individual to follow.
The dose was established through dose-finding work. A Phase 2 randomized, placebo-controlled study evaluated subcutaneous bremelanotide at 0.75, 1.25, and 1.75 mg in premenopausal women with female sexual dysfunction, which supported advancing the 1.75 mg dose into Phase 3 [8]. Early development also explored other routes and higher figures: intranasal dose-escalation in men reached roughly 7-20 mg, and a Phase 1 obesity protocol administered subcutaneous doses up to 2.5 mg, up to three times daily for 15 days — a research protocol only, and not an approved or recommended regimen [1]. The approved route is subcutaneous; the intranasal route was discontinued in development due to pharmacokinetic variability.
How long PT-141 lasts (half-life and timing)
After a subcutaneous dose, bremelanotide reaches peak blood concentration quickly — a median time to maximum (Tmax) of about 0.5 to 1.0 hours — and is then cleared with a terminal half-life of approximately 2.7 hours (range 1.9-4.0 hours) per the prescribing information [11]. Early intranasal studies reported a comparable half-life of 1.85-2.09 hours.
In practical pharmacology terms, that is a short-acting, fast-on profile — which is why the approved use is as needed, taken ahead of anticipated activity rather than dosed continuously [11]. The supporting parameters: a volume of distribution of about 25.0 L, clearance of about 6.5 L/hr, roughly 21% serum protein binding, and metabolism by hydrolysis of the cyclic-peptide amide bonds and by peptidase digestion [11].
PT-141 half-life
The terminal PT-141 half-life is approximately 2.7 hours after subcutaneous administration, with a labeled range of 1.9 to 4.0 hours [11]. The molecule's cyclic lactam structure confers greater stability than the linear melanocortin peptides it is related to, but it is still a short-acting agent — its effect on desire in the fMRI study persisted for up to 24 hours even though the drug itself is cleared within hours, a reminder that a downstream behavioural effect can outlast the molecule's presence in blood [5][11].