PT-141
Bremelanotide
PT-141 (bremelanotide) is a melanocortin receptor agonist that works through the central nervous system to increase sexual desire. Unlike PDE5 inhibitors (Viagra, Cialis) which act on blood flow, PT-141 acts on the brain — specifically MC3R and MC4R receptors in the hypothalamus. It is FDA-approved as Vyleesi for premenopausal women with hypoactive sexual desire disorder (HSDD), and is used off-label by men as well.
Quick Reference
How It Works
PT-141 is a synthetic analog of alpha-melanocyte-stimulating hormone (alpha-MSH). It activates melanocortin receptors MC3R and MC4R in the hypothalamus, which are involved in sexual arousal pathways.
PT-141 (central action)
- Acts on the brain (hypothalamus)
- Increases sexual desire and arousal
- Works for both men and women
- Not dependent on blood flow mechanics
PDE5i (peripheral action)
- Acts on blood vessels
- Increases blood flow to genitals
- Primarily for men (erectile function)
- Does not increase desire
Dosing Protocols
PT-141 is used on an as-needed basis, not daily. Inject subcutaneously approximately 45 minutes before anticipated sexual activity.
Starting Dose
0.5-1 mg
As needed
45 min before activity
Start low to assess tolerance. Nausea is the most common side effect and is dose-dependent. Many users find 1 mg effective with minimal side effects.
Standard Dose
1.5-2 mg
As needed
45 min before activity
Most common effective dose. FDA-approved dose for Vyleesi is 1.75 mg. Do not exceed 1 dose per 24 hours.
FDA Guidelines (Vyleesi)
1.75 mg
No more than 1x per 24 hours
At least 45 min before activity
FDA-approved dose for premenopausal women with HSDD. Max 8 doses per month. Auto-injector in the abdomen or thigh.
Important: Do not use PT-141 more than 8 times per month. Do not use more than once in 24 hours. PT-141 can cause temporary blood pressure elevation — individuals with uncontrolled hypertension or cardiovascular disease should consult their physician.
Reconstitution Guide
Example: 10 mg vial + 2 mL BAC water
Concentration: 10,000 mcg / 2 mL = 5,000 mcg/mL (5 mg/mL)
For 1 mg dose: 1,000 / 5,000 = 0.20 mL = 20 units
For 1.75 mg dose: 1,750 / 5,000 = 0.35 mL = 35 units
For 2 mg dose: 2,000 / 5,000 = 0.40 mL = 40 units
Doses per vial: 10 mg / 1.75 mg = ~5 doses at 1.75 mg
Injection Sites
PT-141 is injected subcutaneously. FDA-approved sites for Vyleesi:
- Abdomen — most common site. At least 2 inches from the navel
- Front of thigh — alternative site. Rotate between left and right
Use a 29-31 gauge insulin syringe. Pinch the skin, insert at 45 degrees, inject slowly.
Side Effects
Side effects are generally transient and resolve within hours. Nausea is the most common and is dose-dependent.
Nausea
Flushing / warmth
Headache
Injection site reaction
Skin darkening (hyperpigmentation)
Temporary blood pressure increase
Managing nausea
- Start with a lower dose (0.5-1 mg) and titrate up
- Avoid heavy meals before injection
- Stay hydrated
- Ginger supplements or ginger tea may help
- Nausea typically decreases with subsequent uses
Research Summary
Bremelanotide significantly increased sexual desire and reduced distress in premenopausal women with HSDD in RECONNECT phase 3 trials, leading to FDA approval
Kingsberg et al., 2019, Obstet Gynecol
PT-141 produced erections in men with erectile dysfunction, including those who did not respond to sildenafil, suggesting a central mechanism independent of PDE5 pathways
Diamond et al., 2004, Int J Impot Res
Bremelanotide activates MC3R/MC4R receptors in the hypothalamus, modulating dopaminergic pathways involved in sexual arousal independent of peripheral blood flow
Pfaus et al., 2007, Neurosci Biobehav Rev
Generally well-tolerated across clinical trials. Transient blood pressure increases of 2-3 mmHg resolved within 12 hours. No serious cardiovascular events attributed to the drug
FDA Vyleesi Prescribing Information, 2019
FAQ
Does PT-141 work for men?
Yes. While FDA-approved only for women (Vyleesi), PT-141 has been studied in men for erectile dysfunction and shown to produce erections even in men who did not respond to Viagra. It is used off-label by men for both desire and erectile support.
How quickly does PT-141 work?
Effects typically begin within 30-60 minutes of injection. Peak effects occur at 1-2 hours. Effects can last 6-12 hours, with some users reporting residual effects into the following day.
Can I combine PT-141 with Viagra/Cialis?
Some users combine PT-141 (central desire) with PDE5 inhibitors (peripheral blood flow). However, both can affect blood pressure. Consult a physician before combining, especially with cardiovascular conditions.
Why does PT-141 cause skin darkening?
PT-141 is derived from alpha-MSH, the same hormone that stimulates melanin production. At higher or repeated doses, it can cause darkening of the skin, gums, or moles. This is typically reversible upon discontinuation.
How should I store PT-141?
Unreconstituted: store refrigerated or at room temperature (refrigerated preferred for longevity). Reconstituted: refrigerate at 2-8°C. Use within 4 weeks of reconstitution.
Is PT-141 addictive?
PT-141 is not considered addictive. It does not produce euphoria or withdrawal symptoms. The FDA labeling does not include addiction warnings. However, it should be used as needed, not on a daily schedule.
Calculate your PT-141 dosing
Get exact syringe units for your vial size and BAC water volume.