PT-141 dosage protocol

What the compound is

Bremelanotide (Vyleesi™), also known as PT-141, is a synthetic peptide analog of the neuropeptide hormone alpha melanocyte-stimulating hormone (α-MSH) (PMID 31429064). It was initially developed by Palatin Technologies (PMID 31429064, PMID 15134289). PT-141 was originally developed as a nasal spray (PMID 15134289). Bremelanotide is administered as a self-administered, on-demand subcutaneous therapy (PMID 31429064).

How it is thought to work

Bremelanotide acts as a melanocortin receptor agonist (PMID 31429064). It has high affinity for the melanocortin type 4 receptor, which is thought to be important for sexual function (PMID 31429064). This mechanism suggests that it may modulate brain pathways involved in sexual response (PMID 31429064).

The physiology of hypoactive sexual desire disorder (HSDD) is complex, and multiple hormones and neurotransmitters are believed to balance excitation and inhibition of sexual desire (PMID 34510696).

Human evidence so far

Bremelanotide is approved in the USA for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD), which is characterized by low sexual desire causing distress or interpersonal difficulty (PMID 31429064). HSDD is a condition where there is a deficiency of sexual thoughts, feelings, or receptiveness to sexual stimulation for at least 6 months, causing personal distress, and not due to another medical condition (PMID 34510696).

Clinical trials in humans have shown that bremelanotide improves the total Female Sexual Function Index (FSFI) score, as well as its desire and arousal subscales (PMID 40543759). It also reduces distress associated with sexual dysfunction (PMID 40543759). Bremelanotide was one of two medications approved for HSDD at the time of one review (PMID 34510696). Earlier, in 2003, a phase IIb trial in men with erectile dysfunction (ED) was completed, and phase III trials were planned for 2005 (PMID 15134289).

Open questions and limitations

While bremelanotide is FDA-approved for HSDD, investigational peptides, in general, require rigorous validation through well-designed clinical trials to establish safety and efficacy for healthspan extension, as noted in a review on therapeutic peptides in gerontology (PMID 42021992). The DSM-5's combined diagnostic category for HSDD and female sexual arousal disorder (FSAD) may inaccurately characterize these distinct conditions, potentially impacting access to effective treatments (PMID 35102537).