PT-141 (Bremelanotide)
Also called Vyleesi
Bremelanotide is the active ingredient in Vyleesi, FDA approved in 2019 for a specific form of low sexual desire in premenopausal women. That approval is much narrower than "boosts libido for everyone."
Overview
What it is
A synthetic peptide that activates melanocortin receptors in the nervous system. It is not testosterone.
How it works
Melanocortin pathways influence sexual response. The prescribing information states the exact mechanism behind its benefit is unknown.
What the research shows
Two RECONNECT trials in 1,267 premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD) found greater improvement in desire and distress scores than placebo over 24 weeks, but not in the number of satisfying sexual events. Small early studies in men measured erectile responses, alone and with sildenafil.
Studied for
- HSDD in premenopausal womenapproved
- Erectile response in mensmall early studies
Safety and regulatory status
Safety and side effects
In the trials, nausea was the most common side effect (about 40%), followed by flushing, injection-site reactions and headache. It can temporarily raise blood pressure and lower heart rate, so it should not be used with uncontrolled high blood pressure or heart disease. Skin darkening can occur and may persist. It should not be combined with oral naltrexone.
Regulatory status
FDA approved (Vyleesi autoinjector) only for acquired, generalized HSDD in premenopausal women. Not approved for men, postmenopausal women or sexual performance. Compounded and research products are not FDA approved.
Mixing and dosing reference
Reference information only. Read before using this section.
PT-141 (10 mg Vial) Dosage Protocol
- Vial
- 10 mg PT-141
- Add diluent
- 3 mL
- Concentration
- 3.33 mg/mL
- 1 unit (U-100)
- 33.33 mcg in 0.01 mL
- Route
- Subcutaneous
- How often
- Once per day (subcutaneous).
- Typical range
- 500–1500 mcg once daily (gradual titration over 16 weeks).
Standard / Gradual Approach
| Week | Daily Dose (mcg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–8 | 500 mcg (0.5 mg) | 15 units (0.15 mL) |
| Weeks 9–12 | 1000 mcg (1.0 mg) | 30 units (0.30 mL) |
| Weeks 13–16 | 1500 mcg (1.5 mg) | 45 units (0.45 mL) |
Nasal Actuation Calculation Table (Placeholders)
| Concentration (mcg/mL) | Pump Output (mL/actuation) | Amount per Actuation (mcg) | Actuations per mL | Total Actuations in Reconstituted Volume |
|---|---|---|---|---|
| [A] | [B] | [A] × [B] | 1 / [B] | [Recon. vol. mL] × (1 / [B]) |
| [C] | [D] | [C] × [D] | 1 / [D] | [Recon. vol. mL] × (1 / [D]) |
How to mix
- Draw 3.0 mL bacteriostatic water with a sterile syringe.
- Inject slowly down the vial wall; avoid foaming.
- Gently swirl/roll until dissolved (do not shake).
- Label and refrigerate at 2–8 °C (35.6–46.4 °F), protected from light.
Dosing details
- Start: 500 mcg daily for the first 8 weeks to assess tolerance.
- Escalate: Increase to 1000 mcg daily during Weeks 9–12.
- Target: 1500 mcg daily during Weeks 13–16 if well tolerated.
- Frequency: Once per day (subcutaneous).
- Timing: Any consistent time; rotate injection sites between abdomen and thighs.
Storage
- Lyophilized: Store at −20 °C (−4 °F) in dry, dark conditions; minimize moisture exposure.
- Reconstituted: Refrigerate at 2–8 °C (35.6–46.4 °F); follow product-specific use-by instructions and avoid freeze–thaw.
- Allow vials to reach room temperature before opening to reduce condensation uptake.
Administration technique
- Clean the vial stopper and skin with alcohol; allow to dry.
- Pinch a skinfold; insert the needle at 45–90° into subcutaneous tissue.
- Do not aspirate for subcutaneous injections; inject slowly and steadily.
- Rotate sites systematically (abdomen, thighs) to avoid lipohypertrophy.
- Discard needles and syringes in a sharps container after one use.
Important notes
- Use new sterile insulin syringes (27–30G, 5/8-inch needle) for each injection; dispose in a sharps container.
- Rotate injection sites (abdomen, thighs) on different days to avoid lipodystrophy or irritation.
- Inject slowly; wait a few seconds before withdrawing the needle.
- Nausea is the most common side effect and tends to be transient; flushing and headache may also occur.
- Document daily dose and site rotation to maintain consistency.
Protocol source: PeptideDosages.com
Common questions
Is PT-141 approved for men?
No. Men's research is limited to small early studies.
Is it better than Viagra?
That has not been established; low desire and erectile difficulty are different problems.
Is a research vial the same as Vyleesi?
No. Vyleesi is a ready-to-use autoinjector with defined manufacturing.
Found in these blends
Related in Hormones and Reproductive Health
Sources and further reading (6)
- FDA. Vyleesi approval letter, June 2019.
- DailyMed. Vyleesi prescribing information.
- Kingsberg SA, et al. Two phase 3 trials of bremelanotide for HSDD. Obstet Gynecol, 2019.
- Diamond LE, et al. Intranasal PT-141 with sildenafil. Urology, 2005.
- MedlinePlus. Bremelanotide injection.
- Source summary: PeptideDosages.com research overview (rewritten for NVO).
Laboratory research material: PT-141 Research Use Only