RESEARCH PROFILE
PT-141
Bremelanotide • Melanocortin Receptor Agonist
PT-141, also known as bremelanotide, is a synthetic cyclic peptide that activates melanocortin receptors involved in central sexual-response pathways.
An FDA-approved bremelanotide drug product, Vyleesi, is approved for acquired, generalized hypoactive sexual desire disorder in premenopausal women.
FDA APPROVED FOR A SPECIFIC INDICATION • CENTRAL MELANOCORTIN SIGNALING • HUMAN PHASE 3 EVIDENCE
PT-141 AT A GLANCE
Generic Name
Bremelanotide
Research Name
PT-141
Compound Type
Synthetic cyclic heptapeptide
Primary Targets
MC3R • MC4R
Primary Research Focus
Sexual desire • Sexual arousal • Central melanocortin signaling
Approved Drug
Vyleesi
Approved Population
Premenopausal women with acquired, generalized HSDD
Regulatory Status
FDA approved for a specific indication and product
IMPORTANT DISTINCTION
PT-141 acts differently from PDE5 inhibitors such as sildenafil or tadalafil.
PDE5 inhibitors primarily affect vascular smooth muscle and blood flow.
PT-141 acts centrally through melanocortin receptors in the brain.
This distinction is important because PT-141 is not simply another erectile-dysfunction drug.
Its FDA-approved indication concerns sexual desire in a defined female population, not erectile function in men.
WHAT IS PT-141?
PT-141 is a synthetic cyclic peptide derived from melanocortin research.
Its pharmaceutical name is bremelanotide.
The compound activates melanocortin receptors involved in regulation of sexual behavior and arousal.
Research has focused on:
Sexual desire
Sexual arousal
Melanocortin signaling
Female sexual dysfunction
Male erectile-function research
Central neuroendocrine pathways
FROM RESEARCH PEPTIDE TO APPROVED DRUG
Bremelanotide progressed through a formal pharmaceutical-development program and ultimately became the active ingredient in Vyleesi, an FDA-approved prescription drug.
That makes PT-141 different from many research peptides whose evidence base remains primarily preclinical.
FORMULATION MATTERS
The FDA-approved Vyleesi product is a specific subcutaneous drug formulation.
Research-grade or compounded PT-141 is not automatically equivalent to Vyleesi.
Differences may include:
Manufacturing controls
Concentration
Excipients
Sterility assurance
Device delivery
Stability
Regulatory oversight
MECHANISM OF ACTION
PT-141 acts primarily through central melanocortin-receptor signaling.
MC3R & MC4R
Bremelanotide activates several melanocortin receptors, with important activity at:
MC3R
MC4R
These receptors are expressed in the central nervous system, including regions involved in sexual and reproductive behavior.
HYPOTHALAMIC SIGNALING
Your Project source identifies the paraventricular nucleus, or PVN, as an important central region involved in PT-141's mechanism.
Activation of melanocortin signaling in this region is associated with downstream neural pathways involved in sexual response.
OXYTOCIN-RELATED PATHWAYS
Preclinical research suggests MC4R activation may influence oxytocin-producing neurons that project toward autonomic and spinal pathways involved in sexual function.
CENTRAL RATHER THAN PERIPHERAL ACTION
PT-141 does not depend primarily on direct vascular smooth-muscle relaxation.
This differentiates it mechanistically from sildenafil and other PDE5 inhibitors.
MC1R ACTIVITY
PT-141 also has some activity at MC1R, the melanocortin receptor involved in pigmentation.
This helps explain why repeated or frequent exposure can be associated with darkening of the skin, gums, or breasts.
MC2R & MC5R
Your Project source describes negligible or substantially lower activity at MC2R and MC5R compared with the central sexual-response receptors.
IMPORTANT MECHANISM LIMITATION
Central melanocortin activation provides a mechanistic basis for sexual-response research.
It does not mean PT-141 universally improves sexual desire, erectile function, orgasm, or relationship-related sexual concerns across all populations.
WHAT THE RESEARCH SHOWS
PHASE 3 HSDD EVIDENCE
The strongest human evidence involves premenopausal women with hypoactive sexual desire disorder, or HSDD.
Your Project profile identifies the two pivotal Phase 3 trials:
RECONNECT 1
RECONNECT 2
Together, these randomized trials enrolled approximately 1,200 women.
Participants self-administered subcutaneous bremelanotide on demand.
SEXUAL DESIRE
The Phase 3 program showed statistically significant improvements in measures of sexual desire compared with placebo.
REDUCTION IN DISTRESS
The trials also reported statistically significant improvements in measures of distress related to low sexual desire.
These outcomes formed the primary basis for FDA approval.
LONG-TERM EXTENSION
Your Project source cites a 52-week open-label extension.
Longer-term follow-up supported continued on-demand use in the approved population and did not identify a fundamentally new safety signal.
FEMALE DOSE-FINDING RESEARCH
Earlier randomized research also evaluated bremelanotide in women with female sexual dysfunction and helped inform later dose selection and Phase 3 development.
MALE ERECTILE-DYSFUNCTION RESEARCH
PT-141 has also been studied in men.
Your Project source cites Phase 2 intranasal studies involving men with erectile dysfunction, including evaluation in some men who did not respond adequately to sildenafil.
These studies showed pharmacodynamic activity.
However:
PT-141 is not FDA approved for erectile dysfunction or for use in men.
INTRANASAL RESEARCH
Earlier clinical studies examined intranasal administration.
The Project profile notes that the FDA-approved product is subcutaneous, not intranasal.
Intranasal PT-141 therefore remains an investigational or off-label context.
IMPORTANT EVIDENCE LIMITATIONS
Phase 3 evidence directly supports:
Premenopausal women
Acquired, generalized HSDD
Subcutaneous bremelanotide
The approved pharmaceutical formulation
The evidence does not establish FDA-approved use for:
Men
Postmenopausal women
Erectile dysfunction
Relationship-specific sexual problems
Intranasal administration
Routine libido enhancement in otherwise healthy individuals
SAFETY & RESEARCH CONSIDERATIONS
Because bremelanotide completed Phase 3 development and received FDA approval, its adverse-event profile is much better characterized than many investigational peptides.
NAUSEA
Nausea is the most commonly reported adverse effect.
Your Project profile notes that it occurred in approximately 40% of users in Phase 3 trials.
It was generally mild to moderate and tended to decrease with repeated use.
FLUSHING
Flushing is also commonly reported, particularly during the first several hours after administration.
HEADACHE
Headache occurred in a subset of trial participants.
INJECTION-SITE REACTIONS
Reported local effects include:
Redness
Pain
Itching
Soreness
TRANSIENT BLOOD-PRESSURE INCREASE
Bremelanotide can cause a temporary rise in blood pressure and reduction in heart rate.
The Project source notes that this effect usually peaks within several hours and returns toward baseline.
Because of this cardiovascular effect, the FDA label contains important contraindications.
UNCONTROLLED HYPERTENSION
Vyleesi is contraindicated in people with uncontrolled hypertension.
CARDIOVASCULAR DISEASE
The FDA-approved product is also contraindicated in people with known cardiovascular disease.
PIGMENTATION CHANGES
Frequent or near-daily exposure can cause focal hyperpigmentation involving areas such as:
Skin
Gums
Breasts
Some pigmentation changes may not fully resolve after discontinuation.
NAUSEA & GASTRIC EMPTYING
Bremelanotide can slow gastric emptying.
This may affect absorption of certain orally administered medications.
NALTREXONE INTERACTION
Your Project source identifies naltrexone as a notable interaction because delayed gastric emptying may reduce oral naltrexone exposure.
PREGNANCY
The FDA label does not recommend use during pregnancy.
IMPORTANT SAFETY DISTINCTION
The safety profile established for Vyleesi should not automatically be transferred to unapproved compounded, intranasal, or research-grade PT-141 formulations.
REGULATORY CONTEXT
BREMELANOTIDE IS FDA APPROVED
Bremelanotide is an FDA-approved active pharmaceutical ingredient in Vyleesi.
The FDA-approved indication is:
Treatment of acquired, generalized hypoactive sexual desire disorder in premenopausal women when the condition is not due to a coexisting medical or psychiatric condition, relationship problems, or medication effects.
FDA APPROVAL DATE
Your Project source identifies 2019 as the year of FDA approval.
APPROVED ROUTE
The approved Vyleesi formulation is administered subcutaneously.
NOT APPROVED FOR MEN
There is no FDA-approved PT-141 indication for men.
NOT APPROVED FOR ERECTILE DYSFUNCTION
Although Phase 2 research exists in men with erectile dysfunction, bremelanotide is not FDA approved for ED.
NOT APPROVED FOR POSTMENOPAUSAL WOMEN
The approved indication specifically applies to premenopausal women.
INTRANASAL PT-141
Intranasal PT-141 has been investigated clinically but is not an FDA-approved route or product.
COMPOUNDED PRODUCTS
Compounded or research-grade PT-141 products are not Vyleesi and should not be represented as FDA-approved formulations.
IMPORTANT REGULATORY DISTINCTION
FDA approval of Vyleesi ≠ approval of every PT-141 product
Approval for HSDD ≠ approval for ED
Approval in premenopausal women ≠ approval in men or postmenopausal women
Phase 2 research ≠ approved indication
ANALYTICAL DOCUMENTATION
Croix maintains available third party analytical documentation only for specific samples and lots that can be matched to corresponding laboratory reports.
LOT SPECIFIC ANALYTICAL DOCUMENTATION
Analytical documentation is displayed only when Croix has a corresponding laboratory report that can be matched to the specific product and lot.
No matching PT-141 COA is currently displayed.
IMPORTANT COA LIMITATION
When analytical documentation becomes available, results should apply only to the specific sample identified in the corresponding laboratory report.
A Certificate of Analysis for one sample does not establish the composition, purity, sterility, safety, efficacy, or characteristics of another sample, lot, batch, or product.
Croix requires the product, strength, lot or batch, sample ID, laboratory, and report date to be matched before analytical documentation is represented as supporting a product.
A passing COA does not establish FDA approval, clinical efficacy, medical suitability, or the characteristics of unrelated lots.
SELECTED RESEARCH & REFERENCES
Kingsberg SA, Clayton AH, Portman D, et al.
Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials.
Obstetrics & Gynecology. 2019.
Pivotal Phase 3 evidence supporting FDA approval.
Simon JA, Kingsberg SA, Portman D, et al.
Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder.
Obstetrics & Gynecology. 2019.
Long-term extension data.
Clayton AH, Althof SE, Kingsberg S, et al.
Bremelanotide for female sexual dysfunction in premenopausal women: a randomized, placebo-controlled dose-finding trial.
Women's Health. 2016.
Dose-finding human clinical research.
Diamond LE, Earle DC, Rosen RC, Willett MS, Molinoff PB.
Research examining intranasal PT-141 in healthy men and men with erectile dysfunction.
International Journal of Impotence Research. 2004/2006.
Male erectile-function research.
Safarinejad MR.
Research examining bremelanotide in women with sexual arousal disorder.
Human female sexual-function research.
Pfaus JG, Shadiack A, Van Soest T, Tse M, Molinoff P.
Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist.
Proceedings of the National Academy of Sciences. 2004.
Preclinical melanocortin sexual-response research.
Mayo Clinic / Merative Micromedex
Bremelanotide subcutaneous drug information.
Clinical safety and dosing reference for the FDA-approved product.
EVIDENCE NOTE
PT-141 has a genuine Phase 3 human evidence base and an FDA-approved drug formulation.
However, the strongest evidence is specific to subcutaneous bremelanotide in premenopausal women with acquired, generalized HSDD.
Research in men, erectile dysfunction, intranasal delivery, or other sexual-function contexts should not be presented as though those uses are FDA approved.
RESEARCH & EDUCATIONAL INFORMATION
This profile is provided for research and educational reference. It does not constitute individualized medical advice.
Bremelanotide is the active ingredient in Vyleesi, an FDA-approved prescription drug for acquired, generalized hypoactive sexual desire disorder in premenopausal women.
That approval applies to a specific drug product, formulation, route, patient population, and indication.
It should not be interpreted as FDA approval of unrelated PT-141 research products or as validation of use in men, postmenopausal women, erectile dysfunction, intranasal administration, or general libido enhancement.
Analytical documentation presented by Croix applies only to the specific samples and lots identified in corresponding laboratory reports.