the 1.75 mg on-demand record

The dosing record, plainly

For the one approved use, the dose on the FDA label is fixed and simple: 1.75 mg injected under the skin, only when needed, no more than once in 24 hours and no more than eight times a month. It is not a daily medicine. The label exists only for the approved prescription product in premenopausal women with distressing low desire; it does not authorize any use in men or other groups. Because bremelanotide is an FDA-approved drug, this dossier reports the labeled figures as labeled figures — not a recommendation, not a protocol. The research-chemical version sold separately has no verified strength, which is exactly why a label dose tells you nothing about what is in a research vial. Below: how the dose was chosen, what the pharmacokinetics look like, and the routes that were studied but not approved.

What the label says

The FDA-approved labeling specifies bremelanotide 1.75 mg subcutaneously into the abdomen or thigh, administered at least 45 minutes before anticipated sexual activity ^[14]. The dosing limits are explicit: no more than one dose per 24 hours, and no more than eight doses per month.

The commercial product is a pre-filled, single-dose, disposable autoinjector pen containing 1.75 mg of bremelanotide in 0.3 mL of solution ^[14]. The autoinjector eliminates manual drawing and measurement; each device is single-use. The on-demand framework — administration before each event, not on a fixed daily schedule — is structurally distinct from chronic-dosing pharmacotherapies for desire and reflects the rapid absorption and short half-life summarized below.

The approved indication is narrow: premenopausal women with acquired, generalized HSDD that is not better accounted for by another medical or psychiatric condition, by a relationship problem, or by a medication or substance effect ^[1]. There is no labeled indication for postmenopausal women, for lifelong HSDD subtypes, or for any male population. The 2024 male-PDE5i-co-formulation Phase 2 program targets that off-label population but is not yet a labeled indication ^[18].

How the 1.75 mg dose was chosen

The 1.75 mg dose did not come from a single landmark study; it came from a Phase 2b dose-finding trial in premenopausal women with female sexual dysfunction that compared subcutaneous doses of 0.75, 1.25, and 1.75 mg against placebo ^[10]. The 1.75 mg arm produced the most consistent statistically significant improvements in FSFI total and desire-domain scores and in distress scales, with a tolerability profile that the program judged acceptable for Phase 3 advancement ^[10]. Lower doses underperformed on efficacy; no higher dose was advanced because the 1.75 mg arm hit the prespecified efficacy thresholds and the safety review preferred the lowest effective dose.

The pivotal Phase 3 program (RECONNECT) carried 1.75 mg subcutaneous on demand into 1,247 randomized premenopausal women with HSDD and reproduced the efficacy signal across both co-primary endpoints over 24 weeks of treatment ^[4]. The 52-week open-label extension at the same dose carried that record into year one ^[5]. The label dose is the Phase 2b winner, validated twice.

Labeled pharmacokinetics

The FDA-approved label characterizes bremelanotide pharmacokinetics following subcutaneous administration of 1.75 mg as follows ^[14]:

• Absolute bioavailability: approximately 100%
• Median Tmax: 1.0 hour
• Mean Cmax: 72.8 ng/mL
• Mean terminal half-life: 2.7 hours (range 1.9–4.0)
• Protein binding: 21%
• Clearance: 6.5 ± 1.0 L/hr
• Elimination: ~64.8% urinary, ~22.8% fecal

Pharmacokinetics are less than dose-proportional across the 0.3–10 mg studied range, with Cmax plateauing at approximately 7.5 mg ^[14]. The short half-life — roughly three hours — is what makes on-demand dosing pharmacologically coherent; the drug clears within a single sexual-activity window rather than accumulating across days. The labeled 45-minute pre-activity administration window aligns with the median 1.0-hour Tmax: the drug is approaching peak concentration as the activity begins.

Routes that were studied but are not approved

The historical development record includes intranasal, intramuscular, and intravenous administration. Intranasal was the original Phase 1/2 path in male erectile dysfunction and produced a statistically significant erectogenic response at doses at or above 7 mg ^[7]. It was abandoned for HSDD development because of dose-related transient elevations in blood pressure that were more pronounced via the intranasal route than via the subcutaneous route ^[7]. Intramuscular and intravenous routes appear only in early Phase 1 pharmacokinetic work and were not advanced ^[15].

Subcutaneous is the only labeled route. Research-grade compound distributed outside the approved subcutaneous autoinjector product is not pharmacy-grade — it has not been tested for identity, purity, sterility, or endotoxin content under the controls that the labeled product satisfies — and is not approved for any self-administration.

Cardiovascular pharmacodynamics and the prescribing context

The labeled cardiovascular profile shows small, transient post-dose increases in blood pressure peaking at two to four hours post-administration — on average approximately +6 mmHg systolic and +3 mmHg diastolic — with corresponding small decreases in heart rate of up to 5 beats per minute, generally returning to baseline by 12 hours ^[15]. The label contraindicates bremelanotide in patients with uncontrolled hypertension or known cardiovascular disease ^[15].

The drug interaction warranting particular attention is with oral naltrexone. Co-administration significantly reduces oral naltrexone exposure — Cmax by approximately 60% and AUC by approximately 40% — by slowing gastric motility ^[16]. The labeling recommends avoiding bremelanotide in patients taking oral naltrexone-containing products for alcohol or opioid use disorder, because reduced naltrexone exposure could compromise addiction treatment ^[16].

All dosing decisions for any individual patient are between that patient and a prescribing clinician. The dossier presents the label; it does not substitute for one.

Co-administration with ethanol

A Phase 1 randomized double-blind crossover study evaluated the 1.75 mg subcutaneous dose co-administered with ethanol (0.6 g/kg) in healthy adults and found no clinically meaningful pharmacokinetic or pharmacodynamic interaction beyond the additive vasovagal effects observed with either agent individually ^[22]. That tolerability profile is consistent with the alcohol-coexposure language reflected in the eventual FDA label.

The absence of a major ethanol interaction does not change the underlying contraindications. The pressor effect, the dosing-frequency limits, and the naltrexone interaction remain in force regardless of whether alcohol is co-administered, and the eight-doses-per-month ceiling is independent of any concurrent intake.

Hepatic safety in surveillance

The NIH LiverTox monograph on bremelanotide reports no association with elevations in serum aminotransferases and no clinically apparent acute liver injury in trials or post-marketing surveillance, placing it in the very low hepatotoxicity-risk category ^[21]. The drug is not on hepatotoxicity watch lists, and routine hepatic monitoring is not part of the standard labeled use.

That low hepatic signal is consistent with the pharmacology: bremelanotide is a small cyclic peptide with primarily renal elimination (~64.8% urinary, ~22.8% fecal) and protein binding of approximately 21% ^[14]. It does not engage the cytochrome P450 system in a clinically meaningful way, which limits the breadth of drug-interaction concern relative to many small-molecule pharmacotherapies.