PT-141 Dosage, half-life & reference guide
Also known as Bremelanotide · PT141 · Vyleesi
An FDA-approved, as-needed treatment for low sexual desire in premenopausal women that acts through brain melanocortin receptors rather than blood flow (flibanserin/Addyi is the other, daily option). Small early studies in men showed erection effects. It's a per-dose compound, taken 1-2 hours before the desired effect.
- Studied range
- 0.5–2 mgstarting dose 1.25 mg
- How often
- As needed
- Half-life
- ~2.7 hours
- Evidence
- ●●●
Established - Route
- SubQ injection
Studied in research — not a recommendation. FDA-approved as Vyleesi: 1.75 mg SubQ as needed, at least 45 minutes before sex (at most once a day, 8 times a month), for premenopausal women with acquired, generalized low sexual desire (HSDD).
How it works.
Melanocortin receptor agonist (mainly MC4R and MC1R at the approved dose) that acts in the brain to increase sexual desire and arousal; the label says the exact mechanism is unknown. Doesn't work by increasing genital blood flow like PDE5 inhibitors (Viagra etc.), though it can briefly raise blood pressure. FDA-approved as Vyleesi (2019) for acquired, generalized HSDD in premenopausal women.
Commonly reported: A noticeable rise in desire and arousal an hour or so after dosing (men often describe firmer or spontaneous erections), nausea that is often worst with the first dose, facial flushing, and headache on dosing days. Frequent use can cause skin darkening.
Half-life & active level
The half-life of PT-141 is ~2.7 hours (FDA label; range 1.9–4.0 hours).
Here's how a typical PT-141 schedule plays out over 48 hours (one-compartment estimate).
An estimate from the half-life above, not a measurement. See your own curve build live in the half-life calculator.
Where PT-141 works.
Sex & hormones
In people. FDA-approved as Vyleesi (2019) for acquired, generalized HSDD in premenopausal women.
An area lights for what a peptide is used for and what people report, with the evidence beside it. It isn’t a promise that it works there.
Week by week.
What to expect in the first 8 weeks
- Onset
- 30–60 minutes
- Peak effect
- 1–3 hours (per dose)
- Duration
- As needed
Day 1–1RCT
First dose — give it 45 minutes
Commonly reported: PT-141 takes 30–60 minutes to kick in, and the arousal feels different from Viagra — more desire, not just mechanics. About 4 in 10 trial users had nausea at some point, most often after the first dose (about 1 in 5), and it usually lasted about 2 hours.
The science
Bremelanotide activates melanocortin receptors (mainly MC4R, plus MC1R), stimulating sexual desire through the CNS rather than vascular pathways; the brain site of its desire effect isn't established. The nausea involves melanocortin signalling in the brainstem's nausea center, though that hasn't been shown in humans.
Sources- FDA Vyleesi label (2019)
- Kingsberg et al. (2019)
Updated Sep 2026
Day 1–7RCT
Nausea fades with experience
If the first dose made you nauseous, it typically gets better: in trials, nausea fell from about 1 in 5 after the first dose to about 3 in 100 later. Lower doses cut nausea only slightly in the dose-finding trial, and the lowest dose tested (0.75 mg) worked no better than placebo.
The science
Clinical trials showed nausea rates declining with repeated dosing (21% after the first dose, about 3% later). In the phase 2b, nausea ran 18%, 22% and 24% at 0.75, 1.25 and 1.75 mg (Clayton 2016). The half-life is about 2.7 hours.
Sources- Kingsberg et al. (2019)
- Clayton et al. (2016)
Updated Sep 2026
Day 1–1RCT
Timing and dose are the two dials that matter
Two practical levers from the trial data: timing and dose. Take it roughly 45 minutes to a couple of hours before, since the effect builds rather than switches on. And because the desire benefit and the nausea both climb with dose, the published range is where the tradeoff is best — higher isn't automatically better here. Find your timing window, then settle on the lowest dose that works for you with your clinician.
The science
In the Vyleesi (bremelanotide) RECONNECT program, the studied dose was 1.75mg SubQ taken ~45 min before activity, with effects developing over 30–60+ minutes given its brain melanocortin (mainly MC4R) mechanism. In the phase 2b dose-finding trial (Clayton 2016), desire/arousal benefit and nausea both showed dose-dependence, which is why the label fixes a single per-use dose and caps frequency rather than encouraging escalation. Ranges and research, not a personal prescription — confirm dose and timing with your clinician.
Sources- Kingsberg et al. (2019)
- Clayton et al. (2016)
Updated Sep 2026
Any dayRCT
Watch for darkening with frequent use
PT-141 also strongly activates MC1R (the tanning receptor), and the darkening of skin and gums climbs with how often you dose: about 1% at up to 8 doses a month versus 38% after 8 daily doses. The FDA label says no more than one dose per 24 hours and no more than 8 per month.
The science
MC1R activation stimulates melanocyte melanin production. The hyperpigmentation risk scales with dosing frequency (1% at ≤8 doses a month vs 38% after 8 consecutive daily doses); whether dose size matters hasn't been tested, since phase 3 used one fixed dose.
Sources- FDA Vyleesi label (2019)
Updated Sep 2026
With Melanotan IICommunity
PT-141 + MT-2: targeted vs broad
PT-141 is a close analog of Melanotan II (it differs only at the tail end of the molecule), developed for sexual function after MT-II caused erections; it didn't drop the tanning receptor. Stacking both is redundant for libido — they hit the same receptors. Some use MT-2 for tanning and PT-141 for targeted as-needed arousal.
The science
Both activate MC4R (libido) and MC1R (tanning). Combining them raises hyperpigmentation risk without additive sexual arousal benefit.
Sources- Hadley & Dorr (2006)
Updated Sep 2026
Any dayRCT
What PT-141 is built on
PT-141 (Bremelanotide) is FDA-approved as Vyleesi for acquired, generalized hypoactive sexual desire disorder in premenopausal women, based on two phase III trials in about 1,250 women (about 3,500 people across the whole development program). In men only small early erection studies exist. The strongest evidence base of any sexual health peptide.
The science
RECONNECT trials (Phase III, n=1247) showed statistically significant improvement in sexual desire and distress scores vs placebo in premenopausal women with HSDD. Small early studies in men (Rosen 2004) produced erections in men who hadn't responded well to Viagra; there is no phase 3 in men.
Sources- Kingsberg et al. (2019)
- FDA approval (2019)
- Rosen et al. (2004)
Updated Sep 2026
Any dayClinical
A combo with ED pills is being trialed
Worth knowing if PDE5 inhibitors (Viagra/Cialis) haven't worked for you: the original developer (Palatin) has been developing PT-141 plus a PDE5 inhibitor specifically for non-responders. It pairs the central desire mechanism with the vascular one. This is being studied, not approved — no results to lean on yet, but it's the most relevant pipeline development for this compound.
The science
Palatin started a phase 2 of bremelanotide given with a PDE5 inhibitor in 2024 (for PDE5i-non-responder erectile dysfunction) and planned a single-injection co-formulation for phase 3; no results have been published, and Palatin's 2026 business update didn't mention it. The combination pairs the central melanocortin (desire) pathway with the peripheral vascular (PDE5) pathway. Framed as in-development; no efficacy results are claimed here.
Sources- Palatin Technologies (2024)
Updated Sep 2026
Day 1 is the day you start it.
FDA-approved as Vyleesi (2019). Phase III data in premenopausal women (RECONNECT); small phase 1/2 erection studies in men. Per-dose compound, not cumulative.
Clinical trial data
Mixing and a typical run.
Example numbers
Reconstitution example
Reconstitute a 10 mg vial of PT-141 with 2 mL of bacteriostatic water and a 1.25 mg dose is 25 units on a U-100 syringe, about 8 doses per vial.
- Vial
- 10 mg
- Water
- 2 mL
- Amount
- 1.25 mg
Draw to25 units
0.3 mL insulin syringe · 30 units
Run notes
- Cycle
- As-needed use. Daily use leads to hyperpigmentation — limit frequency.Community practice — opinions vary. Not a clinical recommendation.
- Timing
- SubQ 1–2 hours before desired effect. Avoid frequent dosing.
- Route
- SubQ injection
- Stacks
- Oxytocin
Safety.
Common side effects
- Nausea (most common)
- Flushing
- Blood pressure elevation
- Spontaneous erections
- Hyperpigmentation with frequent use
Goes with.
Questions people ask.
What is PT-141?
An FDA-approved, as-needed treatment for low sexual desire in premenopausal women that acts through brain melanocortin receptors rather than blood flow (flibanserin/Addyi is the other, daily option). Small early studies in men showed erection effects. It's a per-dose compound, taken 1-2 hours before the desired effect.
How is PT-141 dosed in research?
The research range for PT-141 is 0.5–2 mg, as needed, 1–2 hours before, with a 1.25 mg starting dose. Studied in research — not a recommendation. FDA-approved as Vyleesi: 1.75 mg SubQ as needed, at least 45 minutes before sex (at most once a day, 8 times a month), for premenopausal women with acquired, generalized low sexual desire (HSDD).
How long does PT-141 last?
The half-life of PT-141 is ~2.7 hours (FDA label; range 1.9–4.0 hours).
What do people report on PT-141?
Commonly reported on PT-141: A noticeable rise in desire and arousal an hour or so after dosing (men often describe firmer or spontaneous erections), nausea that is often worst with the first dose, facial flushing, and headache on dosing days. Frequent use can cause skin darkening.
Is PT-141 safe?
The research basis for PT-141 is established: clinical trials or FDA-approved use exists. Common side effects in the library: nausea (most common), flushing, blood pressure elevation, spontaneous erections and hyperpigmentation with frequent use.
What does PT-141 stack with?
Common stacks for PT-141: Oxytocin.
Research.
Reference.
- Cadence
As needed
As needed, 1–2 hours before
- Half-life
~2.7 hours
~2.7 hours (FDA label; range 1.9–4.0 hours)
- Research basis
●●●
EstablishedClinical trials or FDA-approved use exists
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