What Is PT-141?
PT-141, also known as Bremelanotide, is a cyclic heptapeptide melanocortin agonist derived from the Melanotan II research programme. Unlike MT-II, PT-141 has greater selectivity for MC4R and MC3R, with reduced off-target effects. In 2019, PT-141 was FDA-approved as Vyleesi (intranasal formulation) for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women — making it the first peptide-based sexual dysfunction treatment approved for women.
Mechanism of Action
PT-141 acts centrally via MC4R activation in the hypothalamus and limbic system, in contrast to PDE5 inhibitors (sildenafil, tadalafil) which act peripherally on smooth muscle. This central mechanism means PT-141 addresses desire and arousal at the neurological level, not just vascular response.
- Increases dopaminergic and oxytocinergic signalling in reward pathways
- Effective in both psychogenic and organic sexual dysfunction models
- Does not require sexual stimulation to initiate effect — a key distinction from PDE5 inhibitors
Clinical Trial Data
- Phase III RECONNECT trials (n=1,247): PT-141 intranasal demonstrated significant increases in satisfying sexual events (SSEs) vs placebo in women with HSDD
- Male research: Early trials showed efficacy for psychogenic erectile dysfunction; not currently approved for this indication
- Common adverse effects: Nausea (40%), flushing (20%), transient blood pressure increase — managed by co-administration with anti-emetics in later protocols
Research Notes
PT-141 is the most clinically validated melanocortin peptide. Research continues into male sexual dysfunction, pain modulation, and inflammation.
Related compounds: Melanotan II, Selank.