PT-141 (Bremelanotide) for Women: Approved Dose and Evidence
PT-141 is bremelanotide, and bremelanotide has exactly one FDA-approved dose: 1.75 mg injected under the skin from a prefilled autoinjector (Vyleesi), for one specific diagnosis in premenopausal women. Here is what the label says, what the phase 3 trials found, and why a vial sold as 'research PT-141' is a different thing.
- The FDA-approved dose is 1.75 mg of bremelanotide injected subcutaneously into the abdomen or thigh with the Vyleesi autoinjector, as needed, at least 45 minutes before anticipated sexual activity — no more than one dose in 24 hours, and more than 8 doses a month is not recommended.
- It is approved only for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD). The label states it is not indicated for postmenopausal women, for men, or to enhance sexual performance. Stop after 8 weeks if there is no improvement.
- In two 24-week phase 3 trials (1,267 women randomized), bremelanotide improved desire and reduced distress more than placebo, but the differences were modest: on a 1.2–6 desire scale, the average gain over placebo was 0.30 and 0.42 points.
- Nausea affected 40% of women on the drug (vs 1.3% on placebo), flushing 20%, and each dose briefly raises blood pressure. Research-grade 'PT-141' has none of these safety data behind the specific product you'd be using.
The only approved PT-141 dose for women is 1.75 mg of bremelanotide injected under the skin, taken as needed at least 45 minutes before anticipated sexual activity, no more than once in 24 hours and, per the label, not more than 8 times a month1. That dose belongs to one product — Vyleesi, a single-dose autoinjector containing 1.75 mg in 0.3 mL — and one indication: premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD)1,2. 'PT-141' is the development name of bremelanotide, and it is also how unapproved research vials are sold. This guide covers what the FDA label and the trials show, and where the approved product ends and research-peptide use begins. The compound's mechanism and background are on our PT-141 reference page.
Who Vyleesi is approved for
The label defines the indication narrowly. Vyleesi treats premenopausal women with acquired, generalized HSDD — low sexual desire that causes marked distress or interpersonal difficulty — and that is not due to a co-existing medical or psychiatric condition, problems with the relationship, or the effects of a medication or drug1. 'Acquired' means desire was previously normal; 'generalized' means the low desire occurs regardless of the type of stimulation, situation or partner1.
The limitations of use are just as specific: Vyleesi is not indicated for HSDD in postmenopausal women or in men, and it is not indicated to enhance sexual performance1. The current DailyMed label keeps the same indication and limitations2. So the approved dose answers a medical question about one diagnosis; it is not a general 'libido dose'.
The approved dose, line by line
| Parameter | What the FDA label says | Why |
|---|---|---|
| Dose | 1.75 mg, subcutaneous, into the abdomen or thigh1 | The only dose tested in the phase 3 program3 |
| Device | Single-dose prefilled autoinjector, 1.75 mg/0.3 mL1 | Fixed dose; nothing to reconstitute or measure |
| Timing | As needed, at least 45 minutes before anticipated sexual activity1 | The label notes the optimal window and the duration of effect are not fully characterized1 |
| Maximum per day | No more than one dose within 24 hours1 | Efficacy of repeat doses within 24 h is not established, and close dosing may add to blood-pressure effects1 |
| Maximum per month | More than 8 doses per month is not recommended1 | Few trial participants exceeded 8; more frequent dosing raises the risk of hyperpigmentation1 |
| When to stop | Discontinue after 8 weeks if there is no improvement1 | The label sets 8 weeks as the point to judge response |
| Storage | At or below 25°C; do not freeze; protect from light1 | No refrigeration required |
In practice, trial participants used it far less than the monthly ceiling. Across both phase 3 trials the median number of injections was 10 over the 24-week double-blind period, and most women used it two to three times a month and no more than once a week1. Pharmacokinetically, bremelanotide peaks in the blood about an hour after injection, its absolute bioavailability under the skin is about 100%, and its mean terminal half-life is about 2.7 hours1 — it is an on-demand drug, not one that builds up over weeks.
What the phase 3 trials showed
Approval rested on RECONNECT: two identical 24-week, randomized, double-blind, placebo-controlled trials (studies 301 and 302) in premenopausal women with HSDD. Of 1,267 women randomized, 1,247 were in the safety population; mean age was 39, and 96.6% were enrolled at U.S. sites3. The two co-primary endpoints were the change in the desire domain of the Female Sexual Function Index (FSFI-D, scored 1.2–6) and the change in distress about low desire (FSDS-DAO item 13, scored 0–4)1.
| Endpoint | Study 301 | Study 302 |
|---|---|---|
| FSFI desire score — mean change, bremelanotide vs placebo | +0.5 vs +0.21 | +0.6 vs +0.21 |
| Difference from placebo in desire (published analysis) | 0.30, P<.0013 | 0.42, P<.0013 |
| Distress score — mean change, bremelanotide vs placebo | −0.7 vs −0.41 | −0.7 vs −0.41 |
| Difference from placebo in distress (published analysis) | −0.37, P<.0013 | −0.29, P=.0053 |
| Left the double-blind phase early, bremelanotide vs placebo | 40% vs 13%1 | 39% vs 25%1 |
Both trials met both endpoints, and the effect was consistent between them1,3. The size of the effect is modest: on a desire scale running from 1.2 to 6, the average gain over placebo was roughly a third to four-tenths of a point3. The label also flags an interpretive problem: far more women on bremelanotide than on placebo dropped out before week 24, so the label adds an exploratory analysis limited to women who completed the treatment period1. Not every woman improves, and the label's instruction to stop at 8 weeks without improvement reflects that.
Longer-term data come from the 52-week open-label extension. Of 856 women eligible after the core phase, 684 enrolled and 272 completed it; the most common drug-related adverse events were nausea (40.4%), flushing (20.6%) and headache (12.0%), and the authors reported no new safety signals4. Because the extension had no placebo group, its efficacy figures are descriptive only4.
Evidence tier: clinical trials — for the approved indication only. The RECONNECT data apply to premenopausal women with acquired, generalized HSDD using the 1.75 mg autoinjector. They do not establish a dose or a benefit for postmenopausal women, for men, or for use as a performance enhancer.
Side effects from the label
| Adverse reaction (phase 3, pooled) | Bremelanotide (n = 627) | Placebo (n = 620) |
|---|---|---|
| Nausea | 40.0% | 1.3% |
| Flushing | 20.3% | 0.3% |
| Injection site reactions | 13.2% | 8.4% |
| Headache | 11.3% | 1.9% |
| Vomiting | 4.8% | 0.2% |
| Cough | 3.3% | 1.3% |
| Fatigue | 3.2% | 0.5% |
Figures are from Table 1 of the Vyleesi label1. Nausea is the defining side effect. It usually began within an hour of the dose and lasted about two hours; it was most common after the first injection (21% of patients) and fell to about 3% with later doses. Thirteen percent of women on the drug took an anti-emetic, and 8% left the trials because of nausea1. Overall, 18% of women on bremelanotide stopped because of adverse reactions, against 2% on placebo1.
Blood pressure and heart rate
Every dose causes a transient rise in blood pressure and a fall in heart rate. In clinical studies the maximum increases were 6 mmHg systolic and 3 mmHg diastolic, peaking 2–4 hours after the dose, with heart rate falling by up to 5 beats per minute; values usually returned to baseline within 12 hours1. For that reason Vyleesi is contraindicated in uncontrolled hypertension or known cardiovascular disease and is not recommended for women at high cardiovascular risk1.
Skin darkening (focal hyperpigmentation)
In the phase 3 trials, focal hyperpigmentation — including of the face, gums and breasts — occurred in 1% of women using up to 8 doses a month, and in none on placebo. In a separate study of daily dosing, 38% developed it after 8 consecutive days. Women with darker skin were more likely to be affected, and resolution was not confirmed in all patients after stopping1. This is the main reason the label discourages frequent use.
Interactions, pregnancy and other cautions
Bremelanotide may slow stomach emptying and delay the absorption of oral medicines; the label specifically says to avoid it with oral naltrexone products used to treat alcohol or opioid dependence, because it can significantly reduce naltrexone levels1. It advises stopping if pregnancy is suspected and using effective contraception during treatment1. Exposure rises with kidney and liver impairment — up to twofold in severe kidney impairment1.
Vyleesi vs 'research PT-141'
Bremelanotide was developed by Palatin Technologies, which ran the phase 3 trials, and licensed to AMAG Pharmaceuticals for North America before FDA approval in 20195. Earlier in development it was also tested intranasally — the label still describes a 20 mg intranasal dose used in an alcohol interaction study1 — but the approved product is the subcutaneous autoinjector. Every number on this page comes from that product.
Powder sold online as 'PT-141' for research is a different situation. It is not Vyleesi, it is not FDA-regulated, and its purity, sterility and actual content are unverified. The approved dose is a fixed 1.75 mg delivered by a device; a research vial has to be reconstituted and drawn up by hand, which adds a measuring step the trials never had (our syringe units guide explains why small-volume measurement is error-prone). Doses above 1.75 mg, daily use and use by men or postmenopausal women sit outside anything FDA reviewed — and the label's hyperpigmentation data show that daily dosing in particular changes the risk picture1.
Questions worth raising with a prescriber
- Does my situation fit the label — premenopausal, acquired and generalized HSDD, not explained by another condition, a relationship issue or a medication?
- Is my blood pressure well controlled, and do I have any cardiovascular risk that makes the transient rise after each dose a concern?
- Am I taking oral naltrexone or any oral medicine whose timing matters, given that bremelanotide can slow absorption?
- What is the plan if nausea is severe after the first dose — an anti-emetic, or stopping?
- How will we judge at 8 weeks whether it is working?
This guide summarizes the FDA label and published trials; it is not personal dosing advice. For the broader safety picture across compounds, see Are peptides safe?, and for how the on-demand pharmacokinetics compare with weekly peptides, the half-life guide.
FAQ
References
Primary sources — PubMed / NEJM / The Lancet.
- U.S. FDA. VYLEESI (bremelanotide injection), for subcutaneous use — Prescribing Information. AMAG Pharmaceuticals. Revised 6/2019. https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/210557s000lbl.pdf
- DailyMed (U.S. National Library of Medicine). VYLEESI (bremelanotide injection) — current label, revised 02/2021. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8c9607a2-5b57-4a59-b159-cf196deebdd9
- Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstet Gynecol. 2019;134(5):899-908. https://pmc.ncbi.nlm.nih.gov/articles/PMC6819021/
- Simon JA, Kingsberg SA, Portman D, et al. Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. Obstet Gynecol. 2019;134(5):909-917. https://pmc.ncbi.nlm.nih.gov/articles/PMC6819023/
- Dhillon S, Keam SJ. Bremelanotide: First Approval. Drugs. 2019;79(14):1599-1606. https://pubmed.ncbi.nlm.nih.gov/31429064/