PT-141

1,267 women

Two 24-week trials randomized 1,267 women. Average desire and distress scores improved over placebo. The number of satisfying sexual events did not significantly increase.¹²⁶⁸

Who the approval covers

The US indication is acquired, generalized hypoactive sexual desire disorder in premenopausal women. Other medical conditions, medicines and relationship problems must be considered when assessing low desire.¹²⁶⁹

How large was the benefit?

The average advantage over placebo was 0.35 points on a desire scale running from 1.2 to 6, and a 0.33-point reduction on a distress item running from 0 to 4. Individual experiences varied.¹²⁶⁸

Longer follow-up

Of 684 participants entering the open-label extension, 272 completed it. Everyone received bremelanotide, and entrants had already completed the earlier trial. The extension describes people able and willing to continue.¹²⁷⁰

Side effects and practical limits

40%

Nausea occurred in 40% of treated participants and 1.3% with placebo. About 8% stopped because of it. A separate trial found that taking ondansetron beforehand did not significantly reduce nausea.¹²⁶⁹

Blood pressure and pigmentation

Each dose can temporarily raise blood pressure and lower heart rate. Uncontrolled hypertension and known cardiovascular disease are contraindications. Focal skin darkening sometimes persisted after treatment stopped.¹²⁶⁹

Timing and stopping

The label specifies use at least 45 minutes before anticipated sexual activity. It recommends no more than eight doses a month and stopping after eight weeks without improvement. The best timing window and duration of benefit remain incompletely established.¹²⁶⁹

Medicines and pregnancy

Delayed stomach emptying can change oral-drug absorption, including naltrexone used for addiction treatment. The label advises effective contraception and stopping if pregnancy is suspected. A completed ten-person milk study has no posted results.^1269,1271

Other uses and newer research

The male evidence

Early studies measured erectile responses with different doses and routes. The frequently quoted 342-man trial is under an Expression of Concern. Its result is uncertain.^{1272,1273,1274,1275}

Brain imaging

A crossover study found altered brain responses to erotic stimuli in 31 women who completed both visits. More reported increased desire during the following day with bremelanotide. In-scanner arousal ratings did not differ.¹²⁷⁶

Weight and kidney research

Short inpatient weight trials and a later tirzepatide combination study offer preliminary findings. The kidney study treated sixteen people and eight finished; only one of seven evaluable participants reached its main protein-reduction threshold.^{1277,1278,1279}

East Asian research

A completed Korean bridging study enrolled 193 women, with no posted results. Chinese sources include an oral-formulation patent tested in dogs. Japanese publications add questionnaire and laboratory-method context.^{1280,1281,1282,1283}

Common questions

01 Who is Vyleesi approved for?

In the United States, Vyleesi is approved for premenopausal women with acquired, generalized hypoactive sexual desire disorder. Low desire must cause distress and must not be explained by another medical or psychiatric condition, a relationship problem, or a medicine or drug.¹²⁶⁹

02 What do acquired and generalized mean?

Acquired means low desire developed after a period of normal sexual desire. Generalized means it occurs across situations, types of stimulation and partners. Those definitions describe the population covered by the approval.¹²⁶⁹

03 How much did it help in the main trials?

Across two 24-week trials, the average benefit over placebo was 0.35 points on the desire scale and a 0.33-point reduction on the low-desire distress item. The desire scale runs from 1.2 to 6; distress runs from 0 to 4. Participants varied in how much benefit they reported.^1268,1269

04 Did participants have more satisfying sexual experiences?

The trials found no significant difference in the number of satisfying sexual events. A separate analysis found that a greater share of encounters was rated satisfying, but that analysis was performed after the fact. The two results measure different things.¹²⁶⁸

05 How often did people stop because of side effects?

In the placebo-controlled trials, adverse reactions caused 18% of Vyleesi recipients and 2% of placebo recipients to stop. Nausea was the most common reason: about 8% stopped because of it.¹²⁶⁹

06 What do we know about longer-term use?

The extension followed 684 volunteers from the original trials for up to another year; 272 completed it. Everyone received bremelanotide. Entrants had already completed the earlier trial without a serious adverse event, so the extension describes a selected group that had stayed in treatment.¹²⁷⁰

07 What if someone takes it for weeks and feels no benefit?

The prescribing information calls for stopping Vyleesi after eight weeks if symptoms have not improved.¹²⁶⁹

08 How common is nausea?

Nausea affected 40% of Vyleesi recipients and 1.3% of placebo recipients in the main trials. It was most common with the first dose and usually lasted about two hours. Thirteen percent of treated participants used an anti-nausea medicine.¹²⁶⁹

09 Does taking ondansetron beforehand prevent the nausea?

A trial in 228 healthy women tested 8 mg of oral ondansetron 30 minutes before a single Vyleesi dose. It did not significantly reduce nausea. The label does not recommend that pretreatment; treatment after nausea starts has not been formally studied.¹²⁶⁹

10 What happens to blood pressure and heart rate?

Each dose can temporarily raise blood pressure and lower heart rate. In the label's clinical studies, maximal increases were about 6 mmHg systolic and 3 mmHg diastolic, peaking two to four hours after dosing. Values usually returned to baseline within 12 hours. Uncontrolled hypertension and known cardiovascular disease are contraindications.¹²⁶⁹

11 Can it darken the skin permanently?

Focal darkening can affect the face, gums and breasts, and resolution was not confirmed in every participant after stopping. About 1% reported it with intermittent trial use. It was much more frequent in a separate daily-dosing study and in people with darker skin.¹²⁶⁹

12 How long does it take to work, and how long does it last?

The label specifies administration at least 45 minutes before anticipated sexual activity. It says the duration of benefit and the best timing window have not been fully established. The approximately 2.7-hour blood half-life covers drug elimination. It does not give the duration of a person's sexual response.¹²⁶⁹

13 Was Vyleesi studied as a daily treatment?

The pivotal HSDD trials used it as needed, typically two or three times a month. Current labeling allows no more than one dose in 24 hours and recommends no more than eight doses a month. Short studies of daily exposure found more pigmentation and do not establish a daily HSDD regimen.¹²⁶⁹

14 Why does the label warn about oral medicines?

Bremelanotide can slow stomach emptying and change how quickly or how much of an oral medicine is absorbed. The label highlights medicines that require a minimum concentration or a rapid onset. Indomethacin and oral naltrexone had important interactions in the pharmacology studies.¹²⁶⁹

15 What is the interaction with naltrexone?

Vyleesi can substantially reduce exposure to oral naltrexone. The label advises avoiding the combination when oral naltrexone is used to treat alcohol or opioid addiction because treatment failure could have serious consequences.¹²⁶⁹

16 Was it tested with alcohol?

A crossover study included 24 healthy adults who received a single intranasal bremelanotide dose with or without alcohol. It found no clinically important pharmacokinetic interaction or orthostatic blood-pressure signal under those conditions. Repeated use and heavier drinking were not tested in that experiment.¹²⁸⁴

17 What is known about pregnancy and breastfeeding?

Human pregnancy data are too limited to estimate risk, and animal studies found developmental harm. The label advises effective contraception and stopping if pregnancy is suspected. A milk-transfer study in ten breastfeeding women finished in 2025, but its registry has no posted results. Milk exposure and infant effects are unresolved.^1269,1271

18 Do kidney or liver problems change exposure?

Yes. Drug exposure rises as kidney function worsens and also rises with mild or moderate liver impairment. The label requires no adjustment for mild or moderate impairment but calls for caution in severe impairment. Severe liver impairment has not been studied.¹²⁶⁹

19 Have liver injuries been reported in the trials?

One acute hepatitis case occurred in the open-label extension. No alternative cause was found, and a role for bremelanotide could not be excluded. The wider development program did not show an imbalance in liver-test abnormalities. The label and publication differ in their account of the patient's exposure and recovery.^1270,1269

20 Does the approval cover men or women after menopause?

No. The current US indication covers premenopausal women with the specified form of HSDD. The older studies in men examined erectile responses, often with different doses and routes.^1269,1272

21 Why is the often-quoted 34% response in men questionable?

It comes from a 2008 intranasal trial whose journal issued an Expression of Concern in 2023. The abstract reports 51 positive clinical results versus 13 with placebo, but does not give the analyzed denominators behind its percentages. The result should stay flagged as uncertain.^1274,1275

22 Has combining it with sildenafil been studied?

An acute crossover study in 19 men tested low-dose sildenafil with intranasal PT-141. The combination increased measured erectile response during laboratory stimulation. These men already responded to Viagra or Levitra; the study did not test a long-term regimen for nonresponders.¹²⁸⁵

23 Do we know exactly how it improves desire?

Bremelanotide activates several melanocortin receptors. A small crossover study found changes in brain responses to erotic stimuli in 31 women who completed both visits. It offers clues about brain processing; the full mechanism of HSDD improvement is unknown.^1269,1276

24 How is the approved product stored?

The Vyleesi autoinjector is stored at or below 25°C, protected from light, and must not be frozen. Those instructions apply to the finished autoinjector formulation; a reconstituted vial has a different stability question.¹²⁶⁹

25 Did the earlier trial find more satisfying sexual events?

Yes. The earlier dose-finding trial reported an increase of 0.7 events a month in the two higher-dose groups combined, versus 0.2 with placebo. Its first secondary outcome failed the prespecified statistical sequence, so later questionnaire results were exploratory. The larger RECONNECT trials did not confirm an increase in event count.^1286,1268

26 Why do summaries quote different response rates?

They use different definitions of improvement. The journal reported responses using its study anchors; FDA favored a larger change on the desire scale than the sponsor had proposed. A response percentage needs its exact definition and placebo comparison to be useful.^1268,1287

27 Has PT-141 been studied for weight loss?

Yes. Two small inpatient trials found reduced food intake and short-term weight loss in women with obesity. Treatment lasted four or fifteen days and used frequent injections. Later combination research used tirzepatide. Long-term weight control remains an investigational use.^1277,1278

28 What did the tirzepatide combination study actually test?

Everyone first received tirzepatide for four weeks, then 96 participants entered four different treatment groups for another four weeks. The company reported 4.4% weight loss with the combination versus 1.6% in the group switched to placebo, measured across the full eight weeks. No detailed peer-reviewed report was available in the cited sources.¹²⁷⁸

29 Is there evidence that PT-141 helps kidney disease?

A small uncontrolled study treated sixteen people with diabetic kidney disease; eight finished treatment. The conference poster reports that one of seven evaluable patients reached its main protein-reduction threshold. Some other measures improved, but substantial dropout and conflicting company summaries leave the size of any benefit uncertain.^1279,1288

30 Is PT-141 the same as Melanotan II?

They are closely related molecules with different chemical endings. Bremelanotide has a free carboxyl group; Melanotan II has a carboxamide. Vyleesi contains a specified bremelanotide acetate formulation. Research or side effects involving one molecule need to be identified accurately before being applied to the other.^1289,1290

31 Have compounded PT-141 injections been recalled?

Yes. FDA's enforcement database returned four batch-specific recall records involving compounded PT-141 and lack of sterility assurance. They concerned products from four compounding businesses, with recalls initiated between 2018 and 2022. These records concern those products and batches; none of the four is a Vyleesi recall.¹²⁹¹

32 What did the newer animal study find?

A 2025 study in female hamsters found that bremelanotide did not increase sexual reward in its conditioning test. It also found no drug-related change in the measured receptor expression. Together with earlier mixed rat findings, it leaves the proposed brain-reward explanation open.¹²⁹²

33 Is there a pill or nasal version?

The US-approved product is a subcutaneous autoinjector. Earlier human studies used nasal sprays. A Chinese patent describes an oral formulation tested in six dogs: a 100 mg capsule produced exposure similar to a 1.75 mg injection, with dose-adjusted absorption above 1%. Human effectiveness and safety of that oral formulation remain unestablished.^{1269,1293,1281}

34 What does research from East Asia add?

A Korean phase 3 bridging study enrolled 193 women and is marked completed, with no posted results. A Chinese patent describes an oral formulation tested in dogs. Japanese papers cover a translated screening questionnaire and laboratory measurement.^{1281,1282,1283,1280}

35 Where does the claim that effects last 24 hours come from?

In a small crossover study, 31 women completed both treatment visits. At follow-up 24 hours later, 21 reported increased desire after bremelanotide and 8 after placebo. They were asked about any increase during that day. The study did not measure a continuous 24-hour effect or establish the best timing before sex.^1276,1294