PT-141 10 mg

PT-141 is the common research name for bremelanotide, a synthetic peptide with a cyclic structure. As a melanocortin receptor agonist, it binds to a receptor family that mediates signals in the central nervous system and in peripheral tissues. It is precisely this breadth of central and peripheral signaling that makes the molecule interesting for research.

Melanocortin receptors: a family with several roles

Melanocortin receptors are G protein-coupled receptors that are activated by the body's own melanocortins such as alpha-MSH. Among other functions, MC1R is involved in skin pigmentation, while MC4R plays a central role in the brain in regulating energy balance and body weight. At therapeutic exposures, bremelanotide binds to MC1R and MC4R; both receptors shape its pharmacological profile. MC1R and MC4R therefore occur in different tissues and can trigger different cellular responses.

Binding to MC4R is considered particularly relevant for central effects. However, there is no exclusive selectivity for this receptor. According to the prescribing information for Vyleesi (bremelanotide), exactly how activation of the melanocortin receptors leads to changes in sexual desire is not fully understood; the mechanism remains an active field of research.

The US approval: acquired, generalized HSDD

The US approval of Vyleesi covers acquired, generalized HSDD in premenopausal women when low sexual desire causes marked distress or interpersonal difficulty and cannot be explained by a medical or psychiatric condition, relationship problems or the effect of a medication. Acquired means that the low desire developed later; generalized means that it is not limited to specific situations.

HSDD describes a reduced sexual desire that is accompanied by distress or interpersonal difficulty. The diagnosis therefore requires more than a situationally low libido and calls for differentiation from explainable causes. Distress is central to the diagnosis, not the mere frequency of sexual activity.

The approval is tied to the finished product that was studied. It covers neither men nor postmenopausal women and does not represent a general enhancement of sexual performance. It does not establish any approval for the research variant.

RECONNECT: desire and distress as endpoints

Two randomized, double-blind, placebo-controlled phase 3 studies investigated bremelanotide in women with HSDD. A total of 1,267 women were enrolled and followed over a 24-week core phase. The two co-primary endpoints assessed sexual desire and distress related to low desire using questionnaires completed by the participants themselves (phase 3 studies of bremelanotide in HSDD).

Compared with placebo, there was a difference of plus 0.35 points in the desire score and a reduction of 0.33 points in the distress score. These values are mean differences on questionnaire scales, not percentages and not a count of sexual events.

A secondary endpoint assessed the number of satisfying sexual events. Here, the prescribing information for Vyleesi reports no significant difference between bremelanotide and placebo. Desire and distress on the one hand, and event frequency on the other, therefore remain measures to be considered separately. The study design accounts for this distinction by treating desire and distress as separate primary endpoints.

Buy PT-141: the research variant

PT-141 is available as a variant with 10 mg of active substance per vial. This figure refers to the amount in the vial, not the concentration. Buy PT-141 now and view the variant in the shop.