PT-141 (Bremelanotide) Half-Life Calculator
PT-141, generically bremelanotide, is an approved medicine — one of the few compounds discussed in this space that carries a regulatory approval. Its half-life is a couple of hours, and it is used on demand rather than on a schedule.
Half-life 2.7 hours · peaks at 1 hour
Every 24 hours.
Half-life
Left at next dose
Bremelanotide (PT-141) · once daily · levels plateau after ~14 hours
Steady-state peak
1 mg
Steady-state trough
0 mg
Accumulation
None
At once daily, each dose has essentially cleared before the next one — levels don't accumulate, they repeat the same rise and fall. Clearance after a dose takes about 14 hours.
This is a modelled estimate of relative levels from published half-life and time-to-peak figures — not a measured blood concentration. Individual pharmacokinetics vary.
Based on a published PT-141 (Bremelanotide) half-life of about 2.7 hours. The chart models RELATIVE levels from a unit dose — enter your own figures to see the shape. It is not a dose recommendation.
Never do this math twice.
The Pep AI app remembers your vials and doses, shows an interactive syringe you draw to, counts down the doses left in each vial, and reminds you when it's time. Free on iOS and Android.
What a 2.7 hours half-life means in practice
A half-life of 2.7 hours against as used dosing means each dose has essentially cleared before the next arrives. That shapes the curve in three ways:
1. One half-life
Half the dose is gone after 2.7 hours. After two half-lives 25% remains, after three 12.5%.
2. What's left at the next dose
Dosing as used means the next dose lands 24 hours later, with about 0% of the previous one still present.
3. Accumulation and plateau
Almost nothing carries over, so levels don't accumulate — each dose repeats the same rise and fall, clearing in about 14 hours.
Worked example
Bremelanotide (PT-141) has a half-life of 2.7 hours. Dosing as used, the next dose arrives 24 hours later with about 0% of the previous one still on board. That's little enough that levels don't build up: each dose rises and falls on its own, clearing in about 14 hours.
Approved, and used on demand
Bremelanotide is FDA-approved under the brand name Vyleesi for hypoactive sexual desire disorder in premenopausal women. That is a specific indication in a specific population, established through clinical trials, with prescribing information written for it.
It is used on demand rather than on a fixed schedule, which makes the accumulation question largely academic — with a half-life of a couple of hours and no regular interval, there is no plateau to reach. It acts at melanocortin receptors, a different family from anything else in this catalogue, which is also why its effect profile has little in common with the compounds it is listed beside.
Frequently asked questions
This calculator is provided for informational and educational purposes only and is not medical advice. Always confirm dosing with a qualified healthcare professional and double-check your own measurements before administering anything.
Built by the Pep AI team.