The Pep Test Guide 2026
The Pep Test Guide 2026U.S. vendor guide
All compounds
Cognitive

PT-141

Also known as: bremelanotide

Melanocortin agonist. Approved as Vyleesi for HSDD. It works centrally.

PT-141

What is PT-141

PT-141, generically bremelanotidee, is a synthetic cyclic heptapeptide and an agonist at several melanocortin receptors, in particular MC4R and MC3R. It is structurally derived from Melanotane-2 but has been specifically modified to dominate the central effects on sexual arousal and the pigmentation effects recede.

PT-141 has real approval: Under the brand name Vyleesi, bremelanotidee was approved by the FDA in 2019 for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. In Germany, Vyleesi is not available in the broad market.

CAS No: 189691-06-3. Molecular weight: 1025.18 g/mol. Amino acid sequence: Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH.

Mechanism of action

Most substances that target sexual function act via vascular mechanisms (PDE-5 inhibitors such as sildenafil) or hormonally (testosterone). PT-141 acts differently: centrally in the brain on the melanocortinergic system.

Activation of MC4R receptors in the hypothalamus, especially in the pre-optical area and paraventricular nucleus, modulates sexual desire and arousal circuits. This pathway is independent of the vascular system and also works in people in whom sildenafil and similar agents do not show sufficient effect.

In men, central activation leads to spontaneous erection in many studies. In women, subjective sexual desire and desire increases, less about vascular effects.

In addition, there are peripheral effects: slight vasoconstriction, slight increase in blood pressure. The pigmentation effects are significantly weaker compared to Melanotane-2, but not zero.

Areas of application in research

  • Hypoactive sexual desire disorder (HSDD) in women: Authorised Vyleesi indication
  • Erectile dysfunction in men: Early studies positive but not pursued commercially
  • Sexual dysfunction in sildenafil non-responders: Small studies show effectiveness
  • Antidepressant-induced sexual dysfunction (SSRI side effects): Off-label indication
  • Obesity: MC4R agonists have saturation effects, but PT-141 is not primarily developed for this
  • Hemorrhagic shock: Early studies, other PT variant (PT-141 is bremelanotidee)

Study situation

The database is relatively solid for a research peptide because bremelanotidee has gone through a complete approval process.

Important works:

  • Clayton et al. (Obstetrics & Gynecology, 2019): RECONNECT studies (Phase 3) in HSDD patients, significant improvement in desire and distress scores
  • Diamond et al. (Journal of Sexual Medicine, 2006): Early studies in men with ED
  • Kingsberg et al. (Menopause, 2019): Additional data on Vyleesi efficacy and safety
  • Phase 1 and Phase 2 Pharmacokinetic Studies

What is clear: PT-141 is reliably central and increases measurable sexual desire and arousal in a significant proportion of users. What remains unclear: long-term safety with repeated use, effect size in men (Vyleesi is approved only for women).

Mixing (reconstitution)

Typical Vial sizes: 5 mg, 10 mg lyophilisate. Vyleesi (approved product) comes as an auto-injector in 1.75 mg single doses.

  • 10 mg Vial with 1 ml bacteriostatic water → 10 mg/ml
  • 10 mg Vial with 2 ml → 5 mg/ml for finer dosage

After mixing cooling 2 to 8 degrees, stability about 6 to 8 weeks. Lyophilisateeeee stable at -20 degrees over years.

Dosage range (research data)

From the Vyleesi authorisation:

  • 1,75 mg subcutaneously, at least 45 minutes before expected sexual activity
  • Maximum 8 doses per month
  • At least 24 hours between two doses

In research protocols for men:

  • 1 to 2 mg subcutaneously, 45 to 90 minutes before sexual activity
  • Not more often than every 72 hours

Effect typically occurs after 30 to 60 minutes, lasts 6 to 8 hours.

Side effects

Well documented from the admission studies:

  • Nausea (often, about 40 percent in phase 3, usually mild)
  • Hot flashes, flushing
  • Headache
  • Temporary increase in blood pressure (5 to 10 mmHg, about 8 hours)
  • Temporary heart rate slowdown
  • Local irritation at the injection site
  • For darker skin type: focal hyperpigmentation in individual cases (weaker than in Melanotane-2)
  • Rare: persistent erection (priapism, in men)

Contraindicated in uncontrolled hypertension or cardiovascular pre-existing disease. The blood pressure effects are real, even if usually mild.

Half-Life and Pharmacokinetics

Elimination half-life: approximately 2.7 hours. Bioavailability subcutaneously around 100 percent. Maximum plasma level after about 60 minutes.

metabolism via peptidic degradation processes. No relevant CYP interactions. Excretion Renal and Biliary.

Clinical effect does not correlate 1:1 with plasma levels because the central effects last longer than the peripheral half-life.

Frequent questions

Does PT-141 really help against ED? In men with psychogenic or mixed ED yes, with noticeable effect in several studies. With purely vascular ED less, then PDE-5 inhibitors are usually more effective.

When to take? 45 to 90 minutes before expected sexual activity. The effect lasts 6 to 8 hours.

Does PT-141 make it darker? Yes, to a small extent. Significantly less than Melanotane-2, but with frequent use or high dose, a slight change in pigment may occur.

Is PT-141 the same as Vyleesi? bremelanotidee is the generic active ingredient in both products. Vyleesi is the approved trademark (women, HSDD). Research-Use-PT-141 has the same substance but no pharmaceutical quality control.

How often can I use PT-141? Vyleesi label: maximum 8 doses per month, at least 24 hours apart. More frequent use is not well studied and potentially associated with blood pressure effects.

Legal status U.S.

As of 2026: bremelanotidee (Vyleesi) is approved in the USA, not in the EU. In Germany, it is not approved as a medicine, but can theoretically be obtained via international pharmacies with private prescription.

Research-use-only distribution exists in parallel, this is a legal grey area when applied to humans.

WADA status: PT-141 is not on the prohibited list (as of 2026), but should be considered with caution in the professional sports context.

Own import: §73 AMG for approved foreign drugs partially allowed, for research-use products not.

Related compounds

  • Melanotane-2Structurally related melanocortin agonist with stronger pigmentation effect
  • Melanotan-1 (afamelanotide)Approved for erythropoietic protoporphyria
  • Sildenafil, Tadalafil: PDE-5 inhibitor, other mechanism
  • Flibanserin (Addyi)Oral agent for HSDD in women, other mechanism

Note: All information is for research information only. These peptides are not approved as medicines in Germany. The contents do not replace medical advice. Application to humans is not legally covered in Germany.