PT-141 protocol
PT-141 / bremelanotide (melanocortin receptor agonist). Dosing on this page comes from a published human trial or an approved product label, cited below.
How PT-141 works
A melanocortin-receptor agonist derived from the alpha-MSH analog melanotan II. It acts centrally on MC4 receptors rather than on the vascular system, which is what distinguishes it mechanistically from PDE5 inhibitors.
PT-141 dosing schedule
From the approved label. Bremelanotide is FDA-approved as Vyleesi for acquired, generalised hypoactive sexual desire disorder in premenopausal women. Note it is an as-needed product with an explicit frequency ceiling — that limit is part of the protocol, not an afterthought.
| Phase | Amount | Frequency | Notes |
|---|---|---|---|
| Approved use | 1.75 mg | As needed, subcutaneous, at least 45 minutes before anticipated activity | The single approved amount. |
| Labelled maximum | 1 dose per 24 hours | No more than 8 doses per month | The frequency ceiling is part of the approved labelling. |
Study length: As-needed use rather than a course. The label caps use at one dose in 24 hours and no more than eight per month.
Reconstitution and measurement
This part is arithmetic and does not depend on the evidence level. Concentration is vial size divided by the bacteriostatic water you add. Draw volume is your target amount divided by that concentration. Units are draw volume times 100, because a U-100 syringe reads 100 units per millilitre. Common vials for PT-141: 10 mg.
- Wipe the stoppers of both vials with an alcohol swab and let them dry.
- Draw the bacteriostatic water with a sterile syringe and inject it slowly down the inside wall of the peptide vial — never straight onto the powder.
- Swirl gently until the solution is clear. Do not shake; foaming and agitation damage peptides.
- Label the vial with the date and concentration, and refrigerate at 2–8 °C protected from light.
Worked example at the calculator defaults: 10 mg + 2 mL of bacteriostatic water = 5 mg/mL, so on a U-100 insulin syringe 1 unit = 50 mcg of PT-141. Change either input and the calculator redoes this for you.
Storage and stability
Supplies math
Whatever amounts your research uses, the planning arithmetic is the same. The calculator runs all of this per compound.
Subcutaneous technique and practical notes
General best practice from clinical injection guidance — the same fundamentals nurses are taught, none of it specific to any compound.
Reported effects
- Nausea is the most frequently reported adverse event in the trials — common enough that the label addresses it directly.
- Transient blood-pressure increase and heart-rate decrease occur after each dose; the label contraindicates use in uncontrolled hypertension or known cardiovascular disease.
- Focal hyperpigmentation was reported with repeated use, consistent with melanocortin activity.
Sourcing PT-141
Whatever you are working with, the documentation matters more than the price. Ask for a batch certificate of analysis whose lot number matches the vial you actually receive — a COA for a different batch tells you nothing about yours.
PT-141 at Summit Research Supply → Grade a COA first
Summit is the supplier we feature and an affiliate link. Our COA checklist applies the same way to any vendor.
