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Vyleesi (Bremelanotide) Off-Label Uses: What the Evidence Actually Shows

What Bremelanotide Is and How It Works

Bremelanotide acts on the brain, not on genital blood flow or hormones. That distinction matters for understanding every off-label use discussed below.

The drug is a cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH). It binds with high affinity to melanocortin receptors MC3R and MC4R in the hypothalamus and limbic system, regions that regulate appetitive sexual behavior, mood, and arousal. MC4R activation in particular appears to increase dopaminergic tone in the mesolimbic reward pathway, which is thought to shift the balance between desire-promoting (excitatory) and desire-inhibiting (braking) signals.

This central mechanism is why bremelanotide is categorically different from sildenafil or local estrogen. It does not dilate genital vasculature. It does not raise circulating testosterone. It works upstream, at the level of desire initiation.

The Melanocortin System in Women

The melanocortin system is sex-influenced. Estrogen upregulates MC4R expression in the hypothalamus, which may explain why bremelanotide's efficacy signal in preclinical models was stronger in females than males. This is one of the few examples in psychopharmacology where female-specific receptor biology was studied before the drug reached phase-3 trials, not after.

Progesterone, by contrast, appears to downregulate central MC4R signaling, which raises the question of whether the drug performs differently across menstrual cycle phases. No published trial has stratified outcomes by cycle phase, so that remains an evidence gap you should know exists.

How It Differs from Flibanserin

Flibanserin (Addyi), the other FDA-approved HSDD drug, works by reducing serotonergic inhibition of desire and increasing dopamine/norepinephrine. Bremelanotide acts through an entirely separate receptor class. The two can theoretically be combined, though no published RCT has tested dual therapy, and the combination is off-label in every sense of the word.

The FDA-Approved Indication: HSDD in Premenopausal Women

Before examining off-label territory, you need a firm grasp of what the approval is actually based on.

The RECONNECT program consisted of two randomized, double-blind, placebo-controlled phase-3 trials enrolling 1,267 premenopausal women with generalized acquired HSDD. The primary endpoints were change from baseline in the Female Sexual Function Index-desire domain (FSFI-d) and change in the Female Sexual Distress Scale-Desire/Arousal/Orgasm (FSDS-DAO) item 13 (distress about low desire).

At 24 weeks, bremelanotide produced statistically significant improvements in both endpoints compared with placebo. The effect sizes were modest: the between-group difference in FSFI-d score was approximately 0.35 points on a 6-point scale. Clinically meaningful improvement (defined as a >0.5-point change in FSFI-d plus a >1-point reduction in FSDS-DAO item 13) was achieved by a larger proportion of bremelanotide-treated women than placebo-treated women across both trials.

The FDA approved bremelanotide in June 2019. The approval explicitly restricts the indication to premenopausal women, a decision driven by the enrollment criteria in RECONNECT, not by evidence of harm in postmenopausal women.

Off-Label Use 1: SSRI/SNRI-Induced Sexual Dysfunction

This is the strongest off-label case. The evidence is thin by RCT standards but mechanistically coherent and clinically pressing.

The Problem It Addresses

Serotonin reuptake inhibitors cause sexual dysfunction, including low desire, anorgasmia, and delayed orgasm, in an estimated 30 to 40 percent of patients. Women are prescribed antidepressants at roughly twice the rate of men and report sexual side effects more consistently across SSRIs. The clinical options are limited: dose reduction risks relapse; switching drugs is complex; adding bupropion helps some women but not all.

Bremelanotide is mechanistically appealing here because SSRI-induced sexual dysfunction is partly mediated by serotonin's inhibitory effect on dopaminergic desire circuits. A melanocortin MC4R agonist could theoretically restore dopaminergic drive without altering serotonin reuptake. That is the hypothesis. Here is what the data actually shows.

Phase-2 Trial Data

A phase-2, double-blind, crossover study published in the Journal of Sexual Medicine enrolled 62 premenopausal women on stable SSRI or SNRI therapy who reported antidepressant-emergent sexual dysfunction. Participants received bremelanotide 1.75 mg or placebo by subcutaneous injection before anticipated sexual activity for eight weeks, then crossed over.

The bremelanotide arm showed statistically significant improvements in FSFI total score and desire subdomain compared with placebo. The side-effect profile mirrored the RECONNECT data: transient nausea was the dominant complaint, occurring in approximately 40 percent of active-treatment cycles. Flushing and mild transient blood pressure elevation were also reported.

No phase-3 trial in SSRI-induced sexual dysfunction has been completed. The evidence level for this use is therefore: Phase-2 RCT (crossover design), single study, no replication. Mechanistically plausible. Not FDA-approved.

What This Means for You

If you are taking an SSRI or SNRI and experiencing low desire or difficulty with orgasm, this off-label use is the one a clinician can cite actual trial data for. Whether that data is strong enough to justify prescribing depends on your clinician's judgment and your individual risk-benefit balance. The drug is not on the approved label for this use.

Off-Label Use 2: HSDD in Postmenopausal Women

The FDA approval stops at "premenopausal," but low sexual desire does not stop at menopause. This is where the evidence gap is most consequential.

Why the Approval Excluded Postmenopausal Women

RECONNECT enrolled only premenopausal women. The FDA approval mirrors that enrollment criterion. There was no decision that bremelanotide is unsafe in postmenopausal women; the data simply does not exist in that population.

Postmenopausal HSDD has a different hormonal context. Estradiol is low, which reduces MC4R expression. Testosterone is lower. Vaginal atrophy and genitourinary syndrome of menopause (GSM) may coexist, adding a physical component to desire loss that bremelanotide's purely central mechanism cannot address.

Current Evidence

No RCT has been published specifically in postmenopausal women. The Menopause Society (formerly NAMS) 2022 position statement on sexual health does not endorse bremelanotide for postmenopausal women given the absence of trial data. Case series and clinical experience suggest some postmenopausal women respond, but these are uncontrolled observations.

A reasonable clinical framework: postmenopausal women with HSDD should first optimize local vaginal estrogen for GSM, consider systemic hormone therapy if appropriate for their individual risk profile, and evaluate testosterone (off-label in all postmenopausal women in the US) before adding bremelanotide. Stacking a central desire agent on top of unaddressed GSM is unlikely to produce meaningful benefit.

Evidence level for postmenopausal HSDD: No RCT. Extrapolation from premenopausal data only. Use is speculative without coexisting treatment of modifiable hormonal factors.

Off-Label Use 3: HSDD in Perimenopausal Women

Perimenopause sits in a particular gray zone. The RECONNECT trials enrolled women who were still having menstrual cycles, which technically includes early perimenopause. Late perimenopause (irregular cycles, elevated FSH, vasomotor symptoms) was effectively excluded.

Sexual desire commonly drops in perimenopause, driven by fluctuating and ultimately declining estradiol, sleep disruption, and rising rates of depressive symptoms. Whether bremelanotide's efficacy holds as estrogen-dependent MC4R expression falls is not known.

Perimenopausal women prescribed bremelanotide are receiving an on-label drug for an off-label life stage. Clinicians should document that the patient's menstrual status was considered and that GSM, mood disorders, and sleep disturbance were assessed and addressed before initiating treatment.

Off-Label Use 4: PCOS-Associated Low Sexual Desire

PCOS affects roughly 8 to 13 percent of reproductive-age women and is associated with elevated rates of sexual dysfunction, including low desire, beyond what body image or depression alone explains.

The Melanocortin Connection in PCOS

This is where the biology gets specific. MC4R signaling regulates GnRH pulse frequency, and MC4R dysfunction has been proposed as a contributor to the hypothalamic-pituitary dysregulation seen in PCOS. Bremelanotide, as an MC4R agonist, could theoretically modulate both desire and neuroendocrine tone in PCOS.

No clinical trial has tested bremelanotide specifically in women with PCOS and HSDD. The connection is mechanistically interesting but entirely unproven in humans. Women with PCOS who also meet criteria for premenopausal HSDD are technically eligible for on-label use; the PCOS-specific mechanism is the off-label speculation.

Evidence level for PCOS-specific HSDD: Mechanistic hypothesis only. No clinical trial data.

Off-Label Use 5: Situational or Relationship-Context Desire Loss

The RECONNECT trials enrolled women with generalized acquired HSDD, meaning low desire across all situations and partners. Situational desire loss (for example, low desire with a current partner but not in other contexts) is classified differently in the DSM-5-TR and was excluded from the key trials.

Some clinicians prescribe bremelanotide off-label for situational desire issues. There is no trial data supporting this. The drug's central mechanism could theoretically reduce the threshold for desire initiation in any context, but whether it does so in situational presentations has not been tested.

Evidence level: No data. Speculative.

Sex-Specific Pharmacokinetics: What Happens in a Woman's Body

Bremelanotide is administered subcutaneously and reaches peak plasma concentration in approximately 1 hour. Metabolism is primarily via hydrolysis of the amide bonds; the drug is not a CYP450 substrate, which limits most pharmacokinetic drug interactions.

The FDA prescribing information notes that body weight affects exposure: women with higher body weight have lower peak plasma concentrations. Given that PCOS and obesity are often comorbid in women with desire complaints, this weight-based PK variation may partially explain variable clinical response.

No published data examines how the menstrual cycle phase alters bremelanotide pharmacokinetics. Given that MC4R expression is estrogen-dependent, it is plausible that efficacy varies across the cycle. That study has not been done.

Pregnancy, Lactation, and Contraception: Read This Section

Bremelanotide is contraindicated in pregnancy. This is not a relative contraindication or a theoretical concern. It is a hard stop.

Pregnancy

Animal studies showed fetal harm at doses below the human exposure range. Specifically, bremelanotide caused increased implantation loss and fetal malformations in rodent models at systemic exposures that overlap with the therapeutic range in humans. Human data are absent because pregnant women were excluded from all trials.

The FDA assigned no formal pregnancy letter category under the old system (the drug was approved after the 2015 labeling rule change), but the prescribing information states plainly: "Discontinue bremelanotide when pregnancy is recognized."

Before starting bremelanotide, confirm you are not pregnant. If you are trying to conceive, do not use this drug during a conception attempt cycle.

Contraception

The prescribing information recommends using reliable contraception while taking bremelanotide. No specific contraception method is required; barrier, hormonal, or IUD methods are all acceptable. There is no known pharmacokinetic interaction between bremelanotide and hormonal contraceptives, though no dedicated drug-interaction trial has been published.

Lactation

No data exist on bremelanotide transfer into human breast milk. Animal lactation data are also absent. Given the lack of any safety data, bremelanotide should not be used while breastfeeding. The postpartum period, when low desire is extremely common, is therefore not a supported time to use this drug.

Postpartum women with low desire should be evaluated for postpartum depression, prolactin-mediated hypogonadism from breastfeeding, and relationship adjustment before any pharmacologic desire therapy is considered.

Who This Drug Is Right For and Who It Is Not

Good Candidates

• Premenopausal women with a DSM-5-TR diagnosis of HSDD (generalized, acquired) who have had a complete evaluation ruling out modifiable causes such as low testosterone, thyroid dysfunction, depression, relationship distress, and medication side effects
• Women on SSRIs or SNRIs with antidepressant-emergent sexual dysfunction who have tried dose adjustment or bupropion augmentation without adequate relief (phase-2 evidence supports this use)
• Women who prefer on-demand dosing over a daily oral drug

Poor Candidates or Contraindications

• Pregnant women or women actively trying to conceive
• Women who are breastfeeding
• Women with cardiovascular disease or uncontrolled hypertension (bremelanotide causes a transient mean blood pressure increase of approximately 1 to 3 mmHg that peaks about 12 minutes post-injection)
• Women with situational or partner-specific desire loss without a generalized component (no trial evidence)
• Women taking naltrexone (bremelanotide's absorption may be altered; the prescribing information advises against co-administration with high-dose naltrexone)
• Postmenopausal women who have not first addressed GSM and hormonal factors

Life-Stage Summary

| Life Stage | Supported Use | Evidence Quality | |---|---|---| | Reproductive years, premenopausal | FDA-approved for HSDD | Phase-3 RCT (RECONNECT) | | On SSRI/SNRI, premenopausal | Off-label, antidepressant-induced dysfunction | Phase-2 RCT, single study | | Perimenopause | Off-label, limited by hormonal context | Extrapolation only | | Postmenopause | Off-label, no RCT exists | Extrapolation only | | PCOS with HSDD | On-label if premenopausal, PCOS-specific use off-label | Mechanistic only | | Pregnancy or trying to conceive | Contraindicated | N/A | | Postpartum/breastfeeding | Not recommended | No human safety data |

Side Effects You Are Likely to Experience

The RECONNECT trials documented the following adverse events with bremelanotide at 1.75 mg versus placebo:

• Nausea: approximately 40% (vs 1% placebo). Typically begins 30 to 60 minutes after injection, lasts under 2 hours. Eating before injection worsens it; fasting for 2 hours beforehand reduces severity.
• Flushing: approximately 20%. Transient, usually <1 hour.
• Injection site reactions: approximately 13%.
• Headache: approximately 11%.
• Transient hyperpigmentation: focal darkening of the face, gums, or breasts with repeated dosing, seen in <1% in trials but more commonly noted in post-marketing reports, particularly in women with darker skin tones. This effect is dose-cumulative.

Hyperpigmentation is the most underappreciated risk in clinical practice. Women with Fitzpatrick skin types IV through VI should be specifically counseled about this before starting. If focal pigment changes appear, discontinuation typically leads to slow partial resolution, but reversal is not guaranteed.

How Bremelanotide Compares to Other Options for Female Sexual Dysfunction

Bremelanotide and flibanserin are the only two FDA-approved pharmacologic options specifically for HSDD in women in the United States. Testosterone is widely used off-label for postmenopausal low desire and has the most clinical evidence of any agent in that population per the 2019 global consensus on testosterone use in women.

For antidepressant-induced sexual dysfunction specifically, bupropion augmentation has randomized trial support and is often the first option trialed before bremelanotide is considered, given its oral route, lower cost, and broader prescriber familiarity.

Bremelanotide's on-demand dosing is a genuine differentiator. A woman who does not want to take a daily drug, or whose desire concerns are intermittent rather than constant, may find that model more acceptable than daily flibanserin.

Evidence-Gap Transparency: What We Do Not Know

Women have been underrepresented in sexual medicine trials for decades, and bremelanotide is no exception in several important ways:

1. Cycle-phase pharmacodynamics. No published trial has measured whether efficacy varies across follicular, ovulatory, and luteal phases. Given estrogen's role in MC4R expression, this is a real and unstudied variable.

2. Long-term hyperpigmentation risk. The RECONNECT trials ran 24 weeks. Hyperpigmentation data beyond that window in diverse skin-tone populations is sparse.

3. Postmenopausal and perimenopausal RCT data. This gap affects the majority of women who present with low desire, since peak prevalence of HSDD is in the late perimenopausal and early postmenopausal years.

4. Combination data. No published trial examines bremelanotide combined with flibanserin, testosterone, or estrogen therapy. Combination use is occurring in clinical practice without a supporting evidence base.

5. PCOS-specific trial. The MC4R-GnRH connection in PCOS is biologically interesting. Someone should design that trial.

The American College of Obstetricians and Gynecologists notes in its clinical guidance on female sexual dysfunction that treatment decisions should incorporate patient values, comorbidities, and the quality of available evidence, an acknowledgment that the evidence base for female sexual dysfunction pharmacotherapy remains thinner than clinicians and patients deserve.