PT-141 Research Information
Melanocortin Receptor Agonist
For Sexual Dysfunction & Libido Research
⚠️ Important: This information is for educational and research purposes only. Always consult with a qualified healthcare professional before use.
📑 Contents
🔬 What is PT-141?
PT-141 (bremelanotide) is a synthetic cyclic heptapeptide melanocortin receptor agonist that acts primarily on melanocortin receptors 3 and 4 (MC3R and MC4R) in the central nervous system [citation:1][citation:3][citation:7]. It was originally developed as a derivative of Melanotan II, where unexpected side effects of sexual arousal and spontaneous erections were observed during clinical testing for tanning [citation:6].
In 2019, the U.S. FDA approved bremelanotide (brand name Vyleesi) for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women [citation:2][citation:3][citation:4]. It is used off-label for men with erectile dysfunction (ED) and low libido [citation:2]. PT-141 is available in pen and freeze-dried vial formulations for research purposes.
⚡ How PT-141 Works
PT-141 works through multiple mechanisms to influence sexual function and arousal:
MC4R Agonist
Binds to MC4R with high affinity (Ki = 0.25 nM), activating central nervous system pathways [citation:7]
Dopamine Release
Increases dopamine release in the medial preoptic area of the hypothalamus [citation:5]
Central Action
Works centrally in the brain, not on the vascular system, unlike PDE5 inhibitors [citation:6]
PT-141 is a metabolite of Melanotan II that lacks the C-terminal amide function [citation:6]. It has approximately 8-fold lower affinity for MC4R than the parent compound, but retains significant biological activity. PT-141 binds to MC1R (Ki = 6.4 nM), MC3R (Ki = 53 nM), MC4R (Ki = 0.25 nM), and MC5R (Ki = 17 nM) [citation:7].
📋 Research Applications
Female Sexual Dysfunction
FDA-approved for HSDD in premenopausal women; studied for arousal disorders [citation:2][citation:3]
Erectile Dysfunction
Studied in men who do not respond to PDE5 inhibitors like Viagra [citation:1][citation:9]
Combination Therapy
Co-administration with PDE5 inhibitors shows enhanced erectile response [citation:9]
Melanocortin Research
Studying central nervous system effects on sexual desire and arousal pathways [citation:11]
📊 Clinical Studies
Phase 1 & 2 Healthy Male Subjects (2004)
- Doses ranging from 0.3 to 10 mg were administered to healthy male subjects, resulting in a statistically significant erectile response at doses greater than 1.0 mg [citation:1][citation:6]
- ED patients were treated with placebo, 4 mg, or 6 mg PT-141 in a crossover design [citation:1]
- The erectile response induced by PT-141 was statistically significant at both doses [citation:1]
- PT-141 was safe and well tolerated in both studies [citation:1]
- Significant erections occurred in patients who do not have an adequate response to PDE5 inhibitors [citation:1][citation:9]
Combination with PDE5 Inhibitors (2006)
- 19 ED patients were given 25 mg sildenafil + 7.5 mg intranasal PT-141 in a randomized cross-over design [citation:9]
- The erectile response from co-administration was significantly greater than sildenafil alone [citation:9]
- Co-administration was safe and well-tolerated without new or increased adverse events [citation:9]
FDA Approval & Clinical Trials (2019)
- FDA-approved dose: 1.75 mg subcutaneous injection, administered approximately 45 minutes before anticipated sexual activity [citation:4]
- Recommended starting dose: 0.1 mg (test dose), then increase gradually [citation:12]
- Not recommended to use more than 2 injections weekly [citation:12]
- Duration of effects: 24-72 hours after administration [citation:2]
💉 Interactive Dosing Guide
Select your vial size and dose to see the corresponding volume, clicks, dosing frequency, and how many doses per vial:
🖊️ Step 1: Select Your Vial Size
💊 Step 2: Select Your Dose
Common research protocols: 0.1-2 mg per dose. FDA-approved dose: 1.75 mg [citation:4][citation:12]
Vial Size
10mg Vial
Selected Dose
1.75 mg
Doses per Vial
5.7 doses
Pen Clicks
52.5 clicks
Volume
0.525 mL
Protocol Level
Level 3 (Advanced)
Recommended Schedule
As needed, max 2x weekly - FDA Protocol [citation:4][citation:12]
⚠️ Do not change your dose unless advised by a qualified professional.
📋 Protocol Level Summary
Based on research protocols: 0.1-2 mg per dose. FDA-approved dose: 1.75 mg [citation:4][citation:12].
| Protocol Level | Target Dose | Frequency | Pen Clicks | Volume (mL) | Who It\'s For |
|---|---|---|---|---|---|
| Level 1 (Starting) | 0.1-0.5 mg | Test dose | 3-15 clicks | 0.03-0.15 mL | First-time users [citation:12] |
| Level 2 (Standard) | 1-1.5 mg | As needed | 30-45 clicks | 0.30-0.45 mL | Titration phase [citation:12] |
| Level 3 (Advanced) | 1.75 mg | As needed | 52.5 clicks | 0.525 mL | FDA-approved dose [citation:4] |
| Level 4 (Maximum) | 2 mg | Max 2x weekly | 60 clicks | 0.60 mL | Maximum recommended [citation:12] |
⚠️ Do not change your dose unless advised by a qualified professional.
💉 Vial Users (Insulin Syringe)
Add 3mL of bacteriostatic water to your freeze-dried vial and mix gently. After reconstitution, use the table below to draw your dose:
Vial Size
10mg vial with 3mL bac water
| Dose | Frequency | Units on Syringe | Volume (mL) | Protocol Level |
|---|
⚠️ Always use a new sterile needle and syringe for each injection.
⚠️ Safety & Precautions
PT-141 has shown a manageable safety profile in clinical studies. The most common adverse effects include nausea (which often diminishes with subsequent doses), injection site reactions, and headache [citation:2][citation:6].
- Nausea: Common, especially during initial dosing; often diminishes with subsequent doses [citation:2]
- Injection site reactions: Redness or tenderness at injection site
- Headache: Occasional and mild [citation:2]
- Flushing: Cutaneous flushing observed during intravenous infusion [citation:6]
Important Safety Considerations:
- FDA-approved for HSDD in premenopausal women; not approved for men [citation:2]
- Contraindicated in patients with uncontrolled high blood pressure or cardiovascular disease due to potential blood pressure increases [citation:2][citation:3]
- Do not use if allergic to PT-141 or any ingredients
- Do not use if pregnant or breastfeeding
⚠️ Warning: PT-141 (bremelanotide) can cause increased blood pressure and should not be used by individuals with uncontrolled hypertension or cardiovascular disease [citation:2][citation:3]. If you experience severe allergic reactions, difficulty breathing, or signs of anaphylaxis, seek immediate medical help.
📚 References
- Rosen RC, Diamond LE, Earle DC, et al. Safety, pharmacokinetics and pharmacodynamic effects of PT-141 in healthy males and ED patients. International Journal of Impotence Research. 2004;16:135-142. [citation:1]
- Poston L. PT-141 Side Effects, Duration, & Benefits. Invigor Medical. June 2023. [citation:2]
- Bremelanotide (PT-141). NCATS Inxight Drugs. [citation:3]
- Bremelanotide PT-141 For Sexual Enhancement. HoumanMD. December 2022. [citation:4]
- PT-141 (acetate). 10xchem.com. [citation:5]
- PT-141 (bremelanotide). Guide to Immunopharmacology. [citation:7]
- PT-141 (bremelanotide) Monograph. Peptide Society. [citation:12]
This information is for educational and research purposes only. Always consult with a qualified healthcare professional.
Last updated: July 2026