PT-141 (bremelanotide): evidence, half-life, and how to track it
PT-141 is another name for bremelanotide, a synthetic cyclic peptide that activates melanocortin receptors (approved label, DailyMed). It is approved in the United States for one use — acquired, generalised hypoactive sexual desire disorder in premenopausal women — and its label states it is not indicated for men, for postmenopausal women, or to enhance sexual performance. The label gives a half-life of about 2.7 hours.
By Tessaro Pty Ltd, the maker of Pepti · Last reviewed
This page is a reference, not a protocol. PT-141 is one of the few compounds covered here with an approved label behind it, which makes the evidence firmer and the boundaries sharper: the approval covers one condition in one population. What follows is what the label and the trials report, what a half-life of a few hours means for a record, and how to log it. It gives no dose figures and no schedule.
Reference
| Property | Value |
|---|---|
| Class / type | Synthetic cyclic seven-amino-acid peptide; melanocortin receptor agonist (approved label, DailyMed); an analogue of alpha-melanocyte-stimulating hormone — (Dhillon, 2019) |
| Mechanism | Activates several melanocortin receptor subtypes, with MC1R and MC4R the most relevant at therapeutic levels; how it improves the labelled condition is unknown (approved label, DailyMed) |
| Route / form | Subcutaneous injection; the approved product is a ready-to-use solution in a single-dose autoinjector (approved label, DailyMed) |
| Regulatory status | Approved in the United States for acquired, generalised hypoactive sexual desire disorder in premenopausal women; not indicated for men, postmenopausal women, or to enhance sexual performance (approved label, DailyMed; Dhillon, 2019) |
| Evidence base | Human — two identical 24-week phase 3 trials, 1,267 women randomised (Kingsberg et al., 2019), with a 52-week open-label extension (Simon et al., 2019) |
| Half-life | Mean terminal half-life about 2.7 hours (range 1.9 to 4.0) after a single subcutaneous injection (approved label, DailyMed) |
What the research shows
PT-141 is another name for bremelanotide, used in its early clinical studies (Diamond et al., Journal of Sexual Medicine, 2006). It is a synthetic peptide analogue of alpha-melanocyte-stimulating hormone with high affinity for the melanocortin-4 receptor (Dhillon, Drugs, 2019). Its approved label describes a cyclic seven-amino-acid peptide that activates several melanocortin receptor subtypes, with MC1R and MC4R the most relevant at therapeutic levels, and states plainly that the mechanism by which it improves the labelled condition is unknown (approved label, DailyMed).
The approval rests on two identical phase 3, randomised, double-blind, placebo-controlled trials. Across them, 1,267 premenopausal women with hypoactive sexual desire disorder were randomised to 24 weeks of as-needed subcutaneous bremelanotide or placebo; women on bremelanotide had statistically significant increases in sexual desire and reductions in related distress compared with placebo, and more nausea, flushing and headache (Kingsberg et al., Obstetrics and Gynecology, 2019). Of the women who completed that phase, 684 entered a 52-week open-label extension and 272 completed it, with no new safety signals reported (Simon et al., Obstetrics and Gynecology, 2019).
How large that benefit is remains contested. A 2024 re-analysis argued that the trials’ efficacy measures have little validity evidence for this condition, that 8 of the 11 efficacy outcomes registered for the trials had gone unpublished, and that effect sizes on those ranged from nil to small; it concluded that the benefits are statistically modest (Spielmans et al., Journal of Sex Research, 2024).
The safety profile is specific and worth knowing. Across the integrated double-blind phase 3 data, nausea affected 40.0% of women on bremelanotide versus 1.3% on placebo, flushing 20.3% versus 1.3%, and headache 11.3% versus 1.9%; focal hyperpigmentation was rare at labelled use but occurred in more than a third of people given it on consecutive days in another study, and blood pressure rose slightly and transiently (Clayton et al., Journal of Women’s Health, 2022). The label adds that the blood pressure rise and heart rate fall follow each injection and usually resolve within 12 hours, that it is contraindicated in uncontrolled hypertension or known cardiovascular disease, and that resolution of the skin darkening was not confirmed in all patients after stopping (approved label, DailyMed).
The boundaries are the point. The approval describes one condition in one population, and the label rules out use for this condition in men or postmenopausal women, and use to enhance sexual performance. It also describes one physical product, a ready-to-use solution in an autoinjector; material supplied as a powder for reconstitution is a different product, described by its own documentation rather than by this label.
Sources (7)
- Bremelanotide injection label, DailyMed (U.S. National Library of Medicine) — indication and limitations of use, mechanism of action, pharmacokinetics, warnings, and storage. View on DailyMed
- Diamond LE, et al., Journal of Sexual Medicine, 2006 — bremelanotide (PT-141), a melanocortin receptor agonist, in premenopausal women with sexual arousal disorder. Find on PubMed
- Dhillon S, Drugs, 2019 — bremelanotide: first approval (review). Find on PubMed
- Kingsberg SA, et al., Obstetrics and Gynecology, 2019 — bremelanotide for hypoactive sexual desire disorder: two randomised phase 3 trials. Find on PubMed
- Simon JA, et al., Obstetrics and Gynecology, 2019 — long-term safety and efficacy: the 52-week open-label extension. Find on PubMed
- Spielmans GI, et al., Journal of Sex Research, 2024 — small effects and questionable outcomes in the phase 3 trials (re-analysis). Find on PubMed
- Clayton AH, et al., Journal of Women’s Health, 2022 — safety profile across the clinical development programme. Find on PubMed
What a half-life of a few hours means for your record
After a single subcutaneous injection, the label reports a median time to peak plasma level of about 1 hour, an absolute bioavailability of about 100%, and a mean terminal half-life of about 2.7 hours, ranging from 1.9 to 4.0 (approved label, DailyMed). A half-life is the time for half of what is present to clear, so most of an injection has cleared within the same day.
Two details matter for a log. The label’s blood pressure effect runs on a similar clock — it follows each injection and usually resolves within 12 hours — so any reading you take means far more with the time since the last injection written beside it. And the label reports that injecting into the abdomen or the thigh made no significant difference to how much reached the bloodstream; the site column in a log records where each injection went, not a difference in exposure.
The half-life calculator on this site projects clearance from a value you enter yourself. For a figure of a few hours it mainly shows how quickly each injection clears; it is only as good as the number you give it, and neither the site nor the app supplies one.
Storage and handling
Because there is an approved product, its handling is specified on a published label: stored at or below 25 °C (77 °F), not frozen, and protected from light (approved label, DailyMed). That label describes a ready-to-use solution in a single-dose autoinjector, so there is nothing to mix. If your own supply is different — a powder in a vial, for instance — its documentation governs, and the record should capture what that documentation says about temperature, light, and how long a prepared vial remains usable.
How to track it in Pepti
Pepti is a record-keeping tool. Tracking PT-141 comes down to the same jobs across the app and the free tools on this site, none of which involves supplying a figure.
Form first. Record whether each entry came from an autoinjector or a vial. They are different products, and a history that mixes them without saying so is hard to read later.
Reconstitution, as variables. If your supply is a powder, the free reconstitution calculator on this site (not the app) takes the diluent volume you added and the amount your vial is labelled with, and returns the concentration and the draw volume in syringe units for the figure you already hold. Every input is yours; none is a dose the site suggests.
Site rotation. The injection-site rotation tracker keeps a 12-site sequence so each entry lands somewhere the last one did not.
Why this page has no dosing section
Most compounds covered in these references are unapproved, and for them there is simply no authorised dose to publish. PT-141 is the harder case: an approved label exists, and it contains a dose and a frequency limit. This page still does not reproduce them.
An approved dose is not a fact about the compound in the abstract; it is an instruction applied to a particular person, with their blood pressure, cardiovascular history and the labelled indication in view. Lifted out of that setting and printed on a reference page, the number stops being guidance. Pepti records the figure you already have, with the date, time, site and vial. The figure belongs to you and whoever directs your use; the record is what we are for.
What a clean PT-141 record holds
Because each injection is cleared within the day and its side effects are time-linked, the record that helps is one where every entry carries its own time and its own notes.
- Date and time — the actual clock time. Effects that follow each injection are only interpretable against it.
- The figure you already have — whatever was decided with whoever directs your use, in the unit you think in. This page does not supply it.
- Product and form — autoinjector or vial, and if a vial, whether it was a powder you reconstituted.
- Injection site — which of the twelve zones, so the next one goes somewhere else.
- Blood pressure, if it is being measured — the reading and how long after the injection it was taken.
- Side effects with dates — nausea, flushing, headache, and any new patch of darker skin with the date it was first noticed, so the history can be shown to whoever directs your use.
- Vial records — if the vial arrived as a powder, the diluent volume, resulting concentration and the date it was mixed.
The free reconstitution calculator on this site (not the app) converts the figures you already have into a draw volume and a count of doses per vial; the peptide tracking app guide shows how to keep your log, the site sequence and your notes on one timeline.
Common questions
What is PT-141?
PT-141 is another name for bremelanotide (Diamond et al., Journal of Sexual Medicine 2006), a synthetic peptide analogue of alpha-melanocyte-stimulating hormone that activates melanocortin receptors, with high affinity for the melanocortin-4 receptor (Dhillon, Drugs 2019). The approved product is given by subcutaneous injection.
Is PT-141 approved?
Yes, as bremelanotide, in the United States, for one use: acquired, generalised hypoactive sexual desire disorder in premenopausal women (Dhillon, Drugs 2019). Its label states that it is not indicated for postmenopausal women, for men, or to enhance sexual performance. Approval for that indication does not make the label's dosing this page's to publish.
What is PT-141's half-life?
The approved label reports a mean terminal half-life of about 2.7 hours, ranging from 1.9 to 4.0 hours, after a single subcutaneous injection, with peak plasma levels at about 1 hour. The half-life calculator on this site works from a value you enter yourself, never one we supply.
Is PT-141 approved for men?
No. The approved label for bremelanotide states that it is not indicated for hypoactive sexual desire disorder in men or in postmenopausal women, and that it is not indicated to enhance sexual performance. Its phase 3 trials enrolled premenopausal women (Kingsberg et al., Obstetrics and Gynecology 2019).
What are the side effects of PT-141?
In the integrated double-blind phase 3 data, nausea affected 40.0% of women on bremelanotide versus 1.3% on placebo, flushing 20.3% versus 1.3%, and headache 11.3% versus 1.9% (Clayton et al., Journal of Women's Health 2022). The label also describes a transient rise in blood pressure after each injection, usually resolving within 12 hours, and focal darkening of the skin whose resolution was not confirmed in all patients after stopping.
Does Pepti tell me what dose to take?
No. Pepti supplies no dose figures, not even for an approved compound like bremelanotide. Dosing on an approved label is a matter for whoever directs your use. Pepti records the figure you already have with the date, time, site and vial, and keeps the 12-zone site sequence.
This page is a reference on published evidence and record-keeping. It does not recommend PT-141 or any other substance, and it provides no dose figure, no titration amount, and no schedule. Bremelanotide is approved only for a specific indication in premenopausal women; decisions about it belong with a qualified clinician.
The Pepti peptide tracker for iPhone keeps the log, the site sequence, the vial records and your notes in one place.
Not medical advice. Pepti is a record-keeping tool, not a medical device.
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