Bremelanotide: research

An as-needed injection for low libido before menopause; nausea is common.

Also called: PT-141, PT141, Vyleesi.

Melanocortin agonists · Melanocortin receptor agonist · Evidence: Approved drug.

A 2022 safety review counted 43 completed studies and 3,500 participants, a minimum, not a complete 2026 count.

Studies

Bremelanotide dosage

Typical reported dose: 1.75 mg as needed, at most once in 24 hours

  • Vyleesi: 1.75 mg as needed: Inject 1.75 mg subcutaneously via the autoinjector to the abdomen or thigh. as needed; no more than one dose within 24 hours, under the skin. Drug label. Studied in: Premenopausal women with acquired, generalized HSDD. (source)
  • Dose finding: 0.75 mg: 0.75 mg as needed; no more than once daily or 16 doses per 4 weeks, under the skin. Studied in a trial. Studied in: Premenopausal women with desire and/or arousal problems. (source)
  • Dose finding: 1.25 mg: 1.25 mg as needed; no more than once daily or 16 doses per 4 weeks, under the skin. Studied in a trial. Studied in: Premenopausal women with desire and/or arousal problems. (source)
  • Dose finding: 1.75 mg: 1.75 mg as needed; no more than once daily or 16 doses per 4 weeks, under the skin. Studied in a trial. Studied in: Premenopausal women with desire and/or arousal problems. (source)
  • RECONNECT: fixed 1.75 mg: 1.75 mg as needed; at least 24 hours apart, under the skin. Studied in a trial. Studied in: Premenopausal women with acquired, generalized HSDD. (source)
  • Early injection: 4 mg: 4 mg single study-visit dose, under the skin. Studied in a trial. Studied in: Men with poor sildenafil response. (source)

Highest studied: Single monitored SC dose, not a repeated-dose safety limit..

These are doses reported in labels, trials or user reports, not a personal plan. Check the source behind each one.

Work out syringe units with the dosing calculator

Bremelanotide side effects and risks

Reported side effects

  • Nausea: 40.0% vs 1.3% placebo; 8% stopped because of nausea., moderate (source)
  • Flushing: 20.3% vs 0.3% placebo., mild (source)
  • Injection-site reactions: 13.2% vs 8.4% placebo., mild (source)
  • Headache: 11.3% vs 1.9% placebo., moderate (source)
  • Vomiting: 4.8% vs 0.2% placebo., moderate (source)
  • Fatigue: 3.2% vs 0.5% placebo., moderate (source)
  • Dizziness: 2.2% vs 0.5% placebo., moderate (source)
  • Temporary blood pressure rise: Maximum mean rises 6/3 mmHg; heart rate fell up to 5 beats/min. Usually resolves within 12 hours., serious (source)
  • Persistent dark patches: About 1% vs 0% placebo with up to 8 monthly doses. Daily dosing caused much higher rates., moderate (source)
  • Acute liver inflammation: One extension case after 10 doses in a year; causality uncertain., serious (source)

Stop and get help if

  • Chest pain, fainting, severe headache or new weakness.: Stop dosing and seek emergency care.
  • Severe or persistent vomiting, or inability to keep fluids down.: Stop dosing and get prompt medical assessment.
  • Yellow eyes, dark urine or severe upper abdominal pain.: Seek urgent assessment for liver injury.
  • A new or changing mole, uneven color, bleeding or a fast-growing spot.: Pause use and arrange prompt skin assessment.
  • An erection lasting 3–4 hours after off-label use in a man.: Seek emergency care; do not repeat the dose.

Who should avoid it

  • uncontrolledBloodPressure: Formal Vyleesi contraindication; each dose can raise blood pressure.
  • heartCondition: Known cardiovascular disease is a formal contraindication.
  • pregnant: Animal studies found fetal harm. Stop if pregnancy is suspected.
  • tryingToConceive: Use effective contraception; pregnancy exposure is insufficiently studied.
  • breastfeeding: Infant safety is unknown. A completed milk-PK registration has no posted results.
  • under18: Pediatric safety and effectiveness have not been established.
  • melanomaOrAtypicalMoles: Precaution for melanocortins. This is not a formal Vyleesi label contraindication.
  • kidneyDisease: Severe impairment increases exposure and may worsen nausea or vomiting.
  • liverDisease: Severe impairment was not studied; moderate impairment increases exposure.
  • other: Higher cardiovascular risk needs review even without diagnosed cardiovascular disease.

Interactions

  • Oral naltrexone: Can greatly reduce naltrexone exposure. Avoid with oral products used for alcohol or opioid addiction.
  • Oral drugs needing reliable absorption: Slower stomach emptying can reduce or delay drug uptake. The label advises avoiding use with threshold-dependent oral drugs.
  • Other melanocortin agonists: Duplicate receptor activity may add pigment or systemic effects. This combination has no established dosing safety.
  • Sildenafil or tadalafil: A small nasal sildenafil study exists. It does not establish safety of injected PT-141 with tadalafil.
  • Ondansetron pretreatment: 8 mg orally 30 minutes before Vyleesi did not prevent nausea and is not recommended for that purpose.
  • Alcohol: A small nasal study found no major interaction at 0.6 g/kg. This does not cover heavy drinking or all health conditions.

Product quality risks

  • Forensic LC-HRMS identified bremelanotide in seized black-market samples; this did not establish safe strength, sterility or stability.
  • Compounded medicines are not FDA-approved. Contamination and incorrect strength can cause serious harm.

How Bremelanotide works

It activates signals in the brain involved in sexual desire and arousal. It also acts on pigment cells, which can darken skin. Its exact pathway for improving low desire is unknown.

  • MC4 receptor: Brain signaling linked to desire, appetite and blood pressure.
  • MC1 receptor: Can increase skin pigment.

Half-life: Mean 2.7 hours after a single injection; range 1.9–4.0 hours.

Gaps: The 43-study count is the 2022 development-program total. Later studies and unpublished pharmacology work prevent an exact current total. Long-term outcomes in men, postmenopausal women and people with major heart disease remain uncertain. No verified stability or sterile shelf-life data were found for home-mixed PT-141 powder. No robust evidence was found for oral troches, daily libido microdosing or repeated same-day rescue doses. No separate clinician-published alternative schedule was retained; seller protocols and unsupported monographs were excluded.

Related to Bremelanotide

Bremelanotide: the short version

Sources

Sources checked: 2026-10-18.

Information only, not medical advice. Peptifacts does not sell anything and does not link to sellers.