PT-141 (bremelanotide) is an MC3R/MC4R agonist FDA-approved for female HSDD — the only peptide with regulatory approval for sexual function via central melanocortin receptor activation.
Product definition
What is PT-141?
PT-141 (bremelanotide) is an MC3R/MC4R agonist FDA-approved for female HSDD — the only peptide with regulatory approval for sexual function via central melanocortin receptor activation.
PT-141 (bremelanotide; Palatin Technologies / AMAG Pharmaceuticals) is a cyclic heptapeptide derived from the Melanotan research program that produced the first FDA-approved pharmacological treatment for female HSDD in 2019. Its structure is an α-MSH ring-closed analog: the N-terminal acetyl group of α-MSH is removed, enabling cyclization that reduces MC1R selectivity while preserving MC3R/MC4R engagement.
The pharmacological mechanism is distinct from other sexual function treatments: PT-141 acts centrally via hypothalamic MC4R activation, a receptor distribution concentrated in the arcuate nucleus, PVN, and VMH — regions governing sexual motivation, appetite, and autonomic function. This CNS mechanism contrasts with PDE5 inhibitors (peripheral vascular) and testosterone (hormonal). The RECONNECT Phase III program documented this mechanism's clinical utility in premenopausal women, providing a validated model for studying CNS-mediated sexual arousal pharmacology.
Research context
How is PT-141 described in the research literature?
PT-141 activates melanocortin receptors (primarily MC3R and MC4R) in hypothalamic circuits, producing central sexual arousal signals without peripheral hormone modulation. Reduced MC1R activity versus Melanotan 2 minimizes tanning effects. Phase III RECONNECT trials demonstrated significant improvement in sexual desire and associated distress in premenopausal women with HSDD.
Compound profile
Key facts about PT-141
- Class
- Cyclic heptapeptide MC3R/MC4R agonist
- Selectivity
- MC3R > MC4R >> MC1R (reduced tanning vs MT-2)
- Molecular weight
- ~1,025 Da
- Half-life
- ~2.7 hours in vivo
- CAS
- 189691-06-3
- Clinical status
- FDA-approved (Vyleesi) for female HSDD, 2019
- Research category
- MC4R neuropharmacology, sexual function, hypothalamic circuits
- Storage
- Lyophilized: −20°C. Reconstituted: 2–8°C, use within 30 days
Research areas
What research areas is PT-141 associated with?
- FDA-approved as Vyleesi (2019) for female HSDD — the only completed regulatory approval for central MCR-mediated sexual function
- MC3R/MC4R selective — reduced MC1R tanning activity versus Melanotan 2 for cleaner receptor dissection
- Central mechanism (hypothalamic MC4R) vs peripheral mechanism — unique pharmacological profile in sexual function research
- Phase III RECONNECT data: statistically significant improvements in desire and distress endpoints
- Reference compound for MC4R neuropharmacology and hypothalamic sexual arousal circuit research
- Derived from the Melanotan program — bridges pigmentation biology research to neuroendocrine function
Research audience
Who researches PT-141?
PT-141 is used by researchers in MC4R neuropharmacology, hypothalamic circuit biology, central sexual arousal mechanisms, melanocortin receptor selectivity studies, and neuroendocrine pharmacology. It is the pharmacologically validated reference compound for any research addressing MC3R/MC4R-mediated sexual function.
Preclinical research overview
What does the preclinical literature say about PT-141?
PT-141 emerged from the Melanotan 2 research program when investigators studying MT-2's pigmentation effects in rats observed unexpected sexual behavior effects — erections and lordosis in treated animals — attributable to MC4R activation in hypothalamic circuits. This discovery pivoted Palatin Technologies' research program toward investigating melanocortin receptor agonism as a mechanism for sexual dysfunction treatment.
The preclinical to clinical progression documented the MC4R sexual arousal pathway step by step: rodent behavioral studies established the mechanism, Phase II trials in humans confirmed dose-dependent effects on arousal and desire in premenopausal women and erectile function in men (though the male indication was not pursued to approval), and Phase III RECONNECT documented the approved HSDD endpoint.
In preclinical research contexts, PT-141 is used to study hypothalamic MC4R biology independent of the sexual function application — the receptor is expressed in circuits governing feeding behavior, energy homeostasis, and autonomic function, making MC4R pharmacology relevant to metabolic neuroscience beyond sexual function research.
Common questions
Frequently asked about PT-141
How does PT-141 differ mechanistically from PDE5 inhibitors like sildenafil?
PDE5 inhibitors (sildenafil, tadalafil) act peripherally — they enhance vascular response to sexual stimulation by preventing cGMP degradation in penile/clitoral tissue. They require sexual stimulation to work and have no central nervous system activity. PT-141 acts centrally via hypothalamic MC4R activation — it generates the CNS sexual arousal signal that drives desire and motivation, independent of peripheral vascular function. The two mechanisms are pharmacologically distinct and potentially complementary in research designs.
Can PT-141 be used in male sexual function research?
Yes — PT-141 has been studied in male erectile function in Phase II trials, where it showed dose-dependent improvements in erection quality. The FDA approval was for female HSDD, but the MC4R mechanism is not sex-specific: the receptor is expressed in both male and female hypothalamic circuits governing sexual motivation. Male sexual function research using PT-141 is an established part of the preclinical and early clinical literature.
What is the storage and stability profile of PT-141?
Lyophilized PT-141 is stable at −20°C. Reconstituted, store at 2–8°C and use within 30 days. The cyclic disulfide bridge is stable under neutral storage conditions but should not be exposed to reducing agents. At approximately 2.7 hours half-life, PT-141 clears relatively quickly — protocols requiring prolonged CNS MCR exposure may need to account for this in dosing design.
Research Use Only
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