library.onepin.app/pt-141 Peptide Education Library
OnePin Peptide Library
Education only, not medical advice◆ 21+◆ Every dose is an example to finalize with a licensed provider

OnePin Peptide Library · Hormonal

Hormonal Cyclic heptapeptide Not FDA-approved · investigational

PT-141

Bremelanotide

Cyclic heptapeptideMelanocortin receptor agonist (MC3R/MC4R)FDA-approved (Vyleesi)Central-acting sexual function enhancer

PT-141 (Bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist FDA-approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. It was derived from Melanotan II but modified to reduce melanogenic (tanning) effects while retaining sexual function enhancement. PT-141 acts centrally in the hypothalamus through MC3R and MC4R activation, enhancing sexual desire and arousal through neural pathways rather than vascular mechanisms (unlike PDE5 inhibitors). It is used as-needed rather than daily.

Quick Start
Route
SubQ injection
Start low
1.75 mg (FDA-approved dose)
Frequency
As-needed, at least 45 min before activity
Timing
No fasting required

Take 45-60 minutes before anticipated activity. As-needed dosing. Nausea is common - consider anti-nausea medication. Max 1 dose per 24 hours, max 8 per month.

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Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.

Tiered Protocols · lowest first
Quick Start
Conservative start
1.75 mg (FDA-approved dose) · SubQ injection · As-needed, at least 45 min before activity
Lowest starting point. Hold about a week to assess tolerance before stepping up.
1.75 mg (FDA-approved dose)
As-needed, at least 45 min before activity
Standard
Libido Enhancement
1.5-2 mg · SubQ · As needed
human clinical trial · FDA Vyleesi label
1.5-2 mg
As needed
Reconstitution CalculatorU-100
050100u
Draw to
— units
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01

How it works

PT-141 activates MC3R and MC4R in the hypothalamus, enhancing sexual desire through central dopaminergic and oxytocinergic pathways. Unlike PDE5 inhibitors (Viagra, Cialis) which act on vascular smooth muscle, PT-141 acts on the brain to increase desire and arousal. This central mechanism means it can address desire-based dysfunction, not just erectile mechanics.

PT-141 activates MC3R and MC4R in the hypothalamus, enhancing sexual desire through central dopaminergic and oxytocinergic pathways. Unlike PDE5 inhibitors (Viagra, Cialis) which act on vascular smooth muscle, PT-141 acts on the brain to increase desire and arousal. This central mechanism means it can address desire-based dysfunction, not just erectile mechanics.

02

What to expect

Early
Days 1–7

45-60 min: Onset of sexual desire enhancement.

Mid
Weeks 2–4

2-4 hours: Peak effects.

Later
Weeks 4–12

4-8 hours: Effects wane. Single-use per 24hr.

03

Evidence

HumanPresent
AnimalStrong
In-vitroPresent
2016Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women: A Randomized, Placebo-Controlled Dose-Finding Trial · Clayton AH, Althof SE, Kingsberg S et al, Women's Health ↗peer reviewed
2022Safety Profile of Bremelanotide Across the Clinical Development Program · Clayton AH, Kingsberg SA, Portman D et al, Journal of Women's Health ↗peer reviewed
2019Bremelanotide for Treatment of Female Hypoactive Sexual Desire · Dhillon S, Keam SJ, Drugs ↗review
04

The honest take

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Central-acting sexual function

Confirmed. FDA-approved. Works on brain desire pathways, not vascular mechanics. Addresses a different aspect of sexual dysfunction than PDE5 inhibitors.

Derived from MT-II

Confirmed. Modified to reduce tanning while retaining sexual function. Some tanning still possible with repeated use.

05

Interactions & stacking

What's safe to combine, and what belongs in a separate pin.

Keep separate

ALL (syringe)PIN ALONE.
MT-IIBoth melanocortin agonists. Overlapping MC receptor activation. Do not use same day.
Blood pressure medsPT-141 can cause transient BP changes. Monitor.
06

Side effects & safety

Commonly reported

  • Nausea (40% in clinical trials)
  • Flushing
  • Headache
  • Injection site reaction

Less common & notes

  • Transient blood pressure elevation or decrease.
  • Skin darkening possible with repeated use (melanocortin effect, less than MT-II).
  • Contraindicated in uncontrolled hypertension.
07

Pharmacokinetics

Illustrative plasma concentration · 24 h
Half-life
2.7h
Peak · Tmax
1h
Elimination
13.5h
Activity
4-8 hours (sexual desire enhancement per single dose)

Storage. Standard BAC water 2-8C. 28 days.

08

Regulatory status

FDA-approved as Vyleesi for HSDD in premenopausal women. Off-label male use. WADA not specifically listed.

Put it to work

Calculate, log & track

Open PT-141 straight into OnePin with your vial and dose pre-filled, then let it handle the syringe math and remind you before the vial runs out.

Open PT-141 in the app →

Go deeper

The guide & community

The complete PT-141 walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.

Join the community ↗
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