PT-141
/P · T one-four-one (breh-meh-LAN-oh-tide)/aka Bremelanotide, Vyleesi, PT 141
A melanocortin receptor agonist that acts in the brain, FDA-approved as an on-demand injection for low sexual desire in premenopausal women.
PT-141: educational research discussion. Not medical advice. Not a protocol for you.Details
- Reported range
- 1.75 mg per dose
- Frequency
- As needed; max 1 per 24 h, 8 per month
- Cycle length
- On demand; label says stop at 8 weeks if no benefit
- Half-life
- ≈ 2.7 h
- Route
- SC autoinjector
Reported figures describe what is published or discussed. None of them is a dose for you.
Mechanism
What it is proposed to do
Bremelanotide is a cyclic seven-amino-acid peptide that activates several melanocortin receptors without much selectivity. The label names MC1R and MC4R as the most relevant at therapeutic doses. MC4R in the brain is involved in sexual function, which is the usual explanation for its effect on desire, but the label states plainly that the mechanism by which it improves HSDD is unknown. MC1R is the pigment-cell receptor, which fits the focal darkening seen with frequent dosing.
- 01
Bremelanotide
1.75 mg SC; peak levels about 1 hour after dosing
established - 02
Melanocortin receptors
Nonselective agonist; MC1R and MC4R most relevant per label
established - 03
Central desire pathways
How MC4R activation changes desire is not established; label says mechanism unknown
proposed - 04
Small gains in desire, less distress
Shown in two Phase 3 RCTs in premenopausal women
established
Half-life. About 2.7 hours per the label, with peak levels roughly 1 hour after an SC dose and near-complete SC bioavailability. Blood pressure and heart-rate effects fade within about 12 hours.
Dosing & cycles
What is reported, and where it comes from
Numbers below are labeled FDA label, clinical trial range or commonly reported range. They describe the published and discussed landscape. They are not instructions and not a protocol for you.
Dosing studio
Every figure is labeled by where it comes from.
Scale view: Vyleesi label dose
Probe at 1.75 mg: at the listed figure Drag it to read the scale. It does not pick a number for you.
Typical cycle, as a calendar
Label pattern: on demand
Sparse doses; 8-week check
Doses tied to anticipated sexual activity, never more than one in 24 hours or eight in a month. The label adds a stop rule: no improvement by 8 weeks, stop. This calendar is an illustration of sparse use, not a schedule.
Cycle patterns
Label pattern: on demand
Doses tied to anticipated sexual activity, never more than one in 24 hours or eight in a month. The label adds a stop rule: no improvement by 8 weeks, stop. This calendar is an illustration of sparse use, not a schedule.
Stacks
What it gets combined with
Why people pair things, and what nobody has tested.
Melanocortin doubling
2 compounds- Why people combine these
- The two are close chemical relatives, and forums sometimes pair them: melanotan II for tanning, PT-141 for libido.
- Caution
- Same receptor family twice. Nausea, flushing, blood-pressure effects and pigmentation would be expected to add up. No study has combined them.
- What is unknown
- No published human data on this combination: dosing, interactions and long-term effects are all unstudied.
Evidence
How much of this is known
Evidence grade
A
Strong human evidence
Multiple adequate human RCTs and/or FDA approval for a defined indication.
How we gradeGrade A for the approved indication, on two Phase 3 RCTs. Effect sizes are modest, satisfying sexual events did not beat placebo, and there is no comparable evidence in men.
Human trial status
Two identical Phase 3 RCTs (RECONNECT, 1,247 premenopausal women, 24 weeks) found statistically significant but small effects: desire scores rose 0.30–0.42 points more than placebo on a 1.2–6 scale, and distress about low desire fell. The number of satisfying sexual events did not differ from placebo. A Phase 2 trial (327 women) supported the 1.75 mg dose. Data in men come from older erectile-dysfunction studies; no male indication has been approved.
Limitations
- Effects are small, and satisfying sexual events did not improve over placebo.
- Trial populations were premenopausal, about 86% white and almost all US-based.
- The largest male trial (intranasal, 342 men) received an expression of concern from its journal in 2023.
- 18% stopped for side effects vs 2% on placebo, with nausea the leading cause.
Sources to read
- Kingsberg SA et al. Bremelanotide for HSDD: two randomized phase 3 trials (Obstet Gynecol 2019)
- Clayton AH et al. Bremelanotide in premenopausal women: randomized dose-finding trial (Womens Health 2016)
- VYLEESI (bremelanotide injection) prescribing information (DailyMed)
- RECONNECT studies 301 and 302, NCT02333071 and NCT02338960 (ClinicalTrials.gov)
- Safarinejad MR, Hosseini SY. Intranasal bremelanotide in sildenafil non-responders (J Urol 2008; expression of concern 2023)
Links open PubMed, DailyMed, FDA or trial-registry searches. We do not cite what we have not described accurately.
Safety
Side effects, cautions, status
Commonly reported effects
- Nausea in 40% vs 1.3% on placebo in Phase 3. 13% needed anti-nausea medication and 8% left the trials over it. It usually eased by the second dose.
- Flushing 20.3%, injection-site reactions 13.2%, headache 11.3%, vomiting 4.8% (placebo: 0.3%, 8.4%, 1.9%, 0.2%).
- Each dose raises blood pressure (up to 6 mmHg systolic, 3 mmHg diastolic) and lowers heart rate (up to 5 bpm), peaking 2–4 hours after dosing and usually back to baseline within 12 hours.
- Focal darkening of the face, gums or breasts: 1% at up to 8 doses a month, 38% in a study of 8 daily doses. It did not resolve in every case.
- 18% of women on bremelanotide stopped for side effects in Phase 3, vs 2% on placebo.
Who should be extra cautious
- Uncontrolled hypertension or known cardiovascular disease. Contraindicated on the label because of the blood-pressure rise after each dose.
- Oral naltrexone or time-sensitive oral drugs. Label: avoid with oral naltrexone products for alcohol or opioid addiction, whose levels bremelanotide can sharply lower. It may also slow gastric emptying and delay absorption of other oral drugs.
- Pregnancy. Human data are too few to judge risk. The label advises effective contraception and stopping if pregnancy is suspected.
- Darker skin. The label reports a higher risk of focal hyperpigmentation in people with darker skin.
- Men. Not approved. Male data come from older erectile-dysfunction studies, and the largest now carries an expression of concern.
Legal & regulatory status
FDA-approved in 2019 as Vyleesi for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD). The label excludes postmenopausal women, men, and use to enhance sexual performance. Anything else is off-label, and research-market "PT-141" is not Vyleesi.
WADA. Bremelanotide is FDA-approved, so the S0 catch-all for unapproved drugs does not apply. We found no listing that names it, but we could not verify the full current list. Confirm with your federation.
Storage & handling, high level
Vyleesi is a single-dose autoinjector (1.75 mg/0.3 mL). The label says store at or below 25 °C (77 °F), do not freeze, protect from light. Research-market powder sold as PT-141 is a different product with no label.
Reconstitution and injection technique are clinical skills. The reconstitution calculator does arithmetic only.
FAQ
Questions people ask about PT-141
Is PT-141 the same thing as Vyleesi?
How big is the effect?
Does it work for men?
How is it different from Viagra?
What is the 8-doses-a-month limit about?
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