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  • How-to guides

    PT-141: Tanning / Libido research guide

    In short: Bremelanotide (PT-141) FDA-approved MC4R agonist for HSDD activates hypothalamic sexual arousal pathways via central melanocortin signaling. t½ 2.7 hours SC. It is studied in preclinical (cell and animal) research and is supplied strictly for laboratory use, not for human or clinical use.

    Not medical advice. PT-141 is a research compound. This guide does not provide dosing, diagnosis, therapy recommendations, or claims about effects in humans.

    PT-141 at a glance

    Compound type
    Research peptide
    Research category
    Tanning / Libido
    Also known as
    PT-141, Bremelanotide, Vyleesi, Bremelanotide Acetate, MC4R Agonist, Cyclic MSH Analogue, Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-OH
    Molecular weight
    1025.20 Da
    Research-grade purity
    >99% HPLC
    Evidence context
    Preclinical / research use only
    Regulatory status
    Not an approved medicine. Supplied as a research compound
    Last reviewed
    16 June 2026

    What to know first

  • MC4R agonism in hypothalamic nuclei activates central sexual arousal pathways independent of peripheral vasodilation
  • FDA-approved first-in-class treatment for generalized hypoactive sexual desire disorder (HSDD)
  • Subcutaneous bioavailability ~100% with rapid Tmax ~1 hour and sustained 4-8 hour biological effect window
  • Central mechanism of action addresses desire and arousal through neurochemical pathway modulation
  • Details and limits sit in the sections below. Research use only.

    What PT-141 is

    PT-141 (bremelanotide, Vyleesi) is an FDA-approved MC4R agonist that drives sexual arousal through central hypothalamic signalling rather than peripheral vasodilation - a fundamentally different mechanism than PDE-5 inhibitors.

    One-paragraph overview from our research datasheet. Still scientific, but faster to read than the full mechanism list below.

    Bremelanotide (PT-141) FDA-approved MC4R agonist for HSDD activates hypothalamic sexual arousal pathways via central melanocortin signaling. t½ 2.7 hours SC.

    Research contexts

    Peer-reviewed papers discuss PT-141 in specific lab settings. The points below reflect research questions, not health claims.

    Research vs. personal use: Literature describes experiments in cells and animals. That is distinct from real-world use. Our products are for laboratory research only.

    Typical study contexts

  • Melanocortin receptor pharmacology in animal or cell systems.
  • UV-response pathways studied for mechanism, not human tanning advice.
  • MC4R agonism in hypothalamic nuclei activates central sexual arousal pathways independent of peripheral vasodilation.
  • FDA-approved first-in-class treatment for generalized hypoactive sexual desire disorder (HSDD).
  • Subcutaneous bioavailability ~100% with rapid Tmax ~1 hour and sustained 4-8 hour biological effect window.
  • Central mechanism of action addresses desire and arousal through neurochemical pathway modulation.
  • Why Tanning / Libido research matters

    These peptides are studied for melanocortin receptor biology and pigmentation. That work is separate from consumer tanning products.

    Mechanisms (technical review)

    Our datasheet lists mechanistic themes from preclinical work. These are research endpoints, not health claims.

  • MC4R agonism in hypothalamic nuclei activates central sexual arousal pathways independent of peripheral vasodilation
  • FDA-approved first-in-class treatment for generalized hypoactive sexual desire disorder (HSDD)
  • Subcutaneous bioavailability ~100% with rapid Tmax ~1 hour and sustained 4-8 hour biological effect window
  • Central mechanism of action addresses desire and arousal through neurochemical pathway modulation
  • MC1R co-activation provides secondary melanogenic effects at therapeutic doses
  • Active metabolite of Melanotan II with isolated sexual function specificity
  • Lab handling & preparation

  • Storage: Lyophilised powder: store in freezer (−20 °C). Reconstituted: refrigerate 1–6 °C, away from sunlight. Use within the validated stability window for the specific batch and formulation.. See the storage guide.
  • Research dosing context: Literature typically discusses 1.75 mg subcutaneously (FDA-approved dose). As needed, at least 45 minutes before anticipated sexual activity. Maximum one dose per 24 hours, ≤8 doses per month SC t½ = 2.7 hr (range 1.9-4.0 hr). Tmax ~1 hr. Vd = 25.0 L. CL = 6.5 L/hr. Protein binding 21%. Excretion: 64.8% urine, 22.8% feces. Most common adverse effect: nausea (40%). Biological effect duration 4-8 hr exceeds plasma half-life. Available as 1.75 mg/0.3 mL autoinjector pen (Vyleesi).
  • Preparation: Follow the reconstitution guide. Confirm volumes with the calculator.
  • Purity check: Use the COA reading guide and the published PT-141 Certificate of Analysis.
  • Common Questions People Are Asking

    What is PT-141?

    PT-141 (bremelanotide) is a cyclic melanocortin-receptor agonist peptide that acts centrally on MC4R arousal pathways. It is the molecule approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. New-U's PT-141 is research-grade material supplied for laboratory use only — not the approved drug and not for human use.

    What does PT-141 do?

    In research and clinical studies PT-141 activates hypothalamic MC4R circuits involved in sexual motivation/arousal — acting on the brain rather than on peripheral blood flow. These are findings for the molecule; New-U supplies research-grade PT-141 for laboratory research only and implies no human effect.

    What does PT-141 do for women?

    The approved drug (bremelanotide / Vyleesi) is indicated for hypoactive sexual desire disorder in premenopausal women, acting on central MC4R arousal pathways. That is the clinical product; New-U supplies research-grade PT-141 strictly for laboratory research, not for human use.

    How long does PT-141 last?

    Published pharmacology describes a short plasma half-life of about 2.7 hours, while the functional effect window reported in studies of the molecule spans roughly 4-8 hours — longer than the circulating peptide, reflecting receptor residence time. This is reported research context only — not human-use dosing guidance. New-U supplies PT-141 for laboratory research only.

    What does the research on PT-141 actually show?

    The pivotal evidence is the RECONNECT program — two identical phase 3 trials in more than 1,200 premenopausal women with HSDD (Kingsberg et al., Obstetrics & Gynecology, 2019) — which reported statistically significant improvements in sexual desire and reductions in associated distress versus placebo, supporting the 2019 FDA approval of Vyleesi. Earlier research also studied the central MC4R mechanism in male erectile function. This is summarised published research about the molecule, not a human-use claim; New-U supplies research-grade PT-141 for laboratory research only.

    Is PT-141 FDA approved?

    The pharmaceutical bremelanotide (Vyleesi) is FDA-approved for HSDD in premenopausal women. That approval applies to the finished prescription drug — NOT to research-grade material. New-U's PT-141 is an unapproved research powder supplied for laboratory research only.

    How is PT-141 different from Viagra or Cialis?

    PDE-5 inhibitors like Viagra work peripherally - they relax smooth muscle and improve blood flow to the genital tissue, which helps with the mechanics of erection. They do nothing about desire or arousal. PT-141 works centrally in the brain, activating hypothalamic MC4R circuits that generate sexual motivation. The two classes target completely different steps and can theoretically even be used together.

    How is PT-141 different from Melanotan-2?

    PT-141 is essentially an active metabolite of MT-2 with a free carboxylic acid at the C-terminus instead of an amide. That single change shifts selectivity toward MC4R-mediated arousal and away from the broader MC1/3/4/5 activity of MT-2 - keeping the sexual effects while reducing pigmentation, nausea, and facial flushing.

    Why is nausea the most common side effect?

    MC4R is expressed in multiple hypothalamic nuclei including the ones that control nausea and appetite, so central MC4R activation inevitably produces some nausea as a dose-dependent effect. In the Vyleesi clinical trials, around 40% of subjects experienced some nausea at the 1.75 mg dose - it is the predictable consequence of hitting MC4R centrally.

    How should PT-141 be stored?

    Keep the lyophilised powder frozen at −20 °C. After reconstitution with bacteriostatic water, refrigerate at 1-6 °C and protect from light. The cyclic structure gives PT-141 good stability in solution within the normal peptide-handling window.

    Is this page medical advice? Can I use PT-141 for my health?

    No, and no. This article is educational only. We do not provide dosing, medical recommendations, or health claims. Our products are sold strictly for laboratory research, not for personal use of any kind.

    Where do I find PT-141 specs, purity certificates and pricing?

    Open the shop listing via “View product details.” There you will see batch specs, the Certificate of Analysis (COA), concentration, purity grade, and available SKUs with current pricing.

    Related peptide guides

    Other compounds researchers often read about alongside PT-141.

  • Melanotan-2 - companion guide
  • Melanotan-1 - companion guide
  • Oxytocin Acetate - companion guide
  • TB-500 - companion guide
  • Scientific sources & further reading

    Primary literature and registries for PT-141, plus mainstream coverage of the peptide category. Research use only - not medical advice.

    Databases & literature:

  • PubMed: peer-reviewed literature on PT-141
  • ClinicalTrials.gov: registered studies on PT-141
  • PT-141: Wikipedia
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  • Ready to order? View full product specs

    Access concentration, batch info, variants, and current pricing on our shop.

    Also known as: PT-141, Bremelanotide, Vyleesi, Bremelanotide Acetate, MC4R Agonist, Cyclic MSH Analogue, Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-OH

    PRECISION. PURITY. PERFORMANCE.

    Research peptides at >99% HPLC-verified purity, third-party tested by Janoshik Analytical & Freedom Diagnostics, with Certificates of Analysis published per released batch. Supplied strictly for laboratory research use.

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    © 2026 New-U Research Compounds · new-u.io

    Research use only — not for human consumption. All products are supplied strictly for laboratory research purposes.

    © 2026 New-U Research Compounds · new-u.io — Copyright held with Hilxera Distribution Services LLC. All rights reserved.