PT-141 Dosage Calculator
Calculate PT-141 (Bremelanotide) injection volumes. Pre-filled for a 10mg vial with 2ml BAC water (5,000 mcg/ml).
PT-141 (Bremelanotide) is a melanocortin receptor agonist derived from Melanotan 2, developed specifically for sexual dysfunction. Unlike PDE5 inhibitors (sildenafil, tadalafil) that work on blood flow, PT-141 acts centrally through MC3R and MC4R receptors in the brain. It is FDA-approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women.
For a 10mg PT-141 vial: add 2ml of bacteriostatic water → concentration is exactly 5000 mcg/ml. A commonly referenced 1000mcg (1mg) research dose = 0.20ml (20 units) on a 100-unit syringe.
Dose Reference Table
Pre-calculated for a 10mg vial + 2ml BAC water = 5,000 mcg/ml concentration. Using a 100-unit (1ml) insulin syringe.
| Dose | Inject Volume (ml) | Syringe Units |
|---|---|---|
| 500mcg | 0.100 ml | 10 units |
| 750mcg | 0.150 ml | 15 units |
| 1000mcg | 0.200 ml | 20 units |
| 1500mcg | 0.300 ml | 30 units |
| 2000mcg | 0.400 ml | 40 units |
About PT-141
PT-141 (Bremelanotide) is a synthetic melanocortin receptor agonist derived from Melanotan II. Unlike Melanotan II which primarily targets MC1R for tanning and weight effects, PT-141 preferentially targets MC3R and MC4R receptors in the brain, which are involved in sexual arousal in both men and women.
PT-141 is FDA-approved under the brand name Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. In research settings, it has been studied for both male and female sexual dysfunction and arousal enhancement.
PT-141 is typically supplied in 10mg vials. Reconstituting with 2ml of bacteriostatic water gives a concentration of 5,000 mcg/ml. The FDA-labeled Vyleesi dose is 1.75mg, administered as needed at least 45 minutes before anticipated sexual activity; in research settings, doses of 0.75–2mg (750–2000mcg) via subcutaneous injection are commonly referenced.
Bremelanotide's mean terminal half-life is approximately 2.7 hours per the Vyleesi label. The label limits use to one dose within 24 hours and notes that more than 8 doses per month is not recommended. Common side effects in research include transient nausea and flushing.
How this calculator works
Every result comes from the same three formulas used for any lyophilized peptide: concentration (mcg/ml) = vial mg × 1,000 ÷ BAC water ml; injection volume (ml) = desired dose mcg ÷ concentration; syringe units = injection volume ml × 100 on a U-100 syringe.
For the preset PT-141 setup on this page: a 10mg vial mixed with 2ml of bacteriostatic water gives a concentration of 5,000 mcg/ml. A 1,000mcg dose then needs 0.20ml, which is 20 units on a 100-unit insulin syringe.
The full methodology, with worked examples and the assumptions behind each formula, is on the methodology page.
Accuracy & limitations
The arithmetic itself is exact — the same inputs always produce the same output. Real-world accuracy depends on things outside the calculator: actual vial contents can vary slightly from the labeled amount within manufacturing tolerance, the BAC water volume should be measured carefully, and syringe readings are taken at the bottom edge of the plunger. Reconstituted peptides also degrade over time (the common guidance is to use within about 28 days refrigerated), which the math does not model. This tool does arithmetic only — it does not recommend doses, and it is not medical advice.
Last reviewed: September 2026 · Content, formulas and sources checked by Kanika