The primary objectives of this clinical trial performed with Vyleesi (Bremelanotide Injection) are:

• to evaluate if Bremelanotide (BMT) is secreted in breast milk of lactating women treated with a single dose of BMT 1.75 mg SC.
• to measure the concentration and characterize the pharmacokinetics of BMT secreted in breast milk of lactating women treated with a single dose of BMT 1.75 mg SC.

This open-label, pharmacokinetic (PK) study will be performed in 10 healthy lactating female subjects between 10 days and 6 months post-partum (inclusive). The maximum duration of subject participation in the study will be approximately 29 days, consisting of 3-week Screening period, a 1 day treatment period, and up to a 7 day follow-up period.

Inclusion Criteria (Main Criteria):

• Female subjects ≥18 to 55 years of age (inclusive) and premenopausal
• Lactating, between 10 days and 6 months postpartum (inclusive).
• Exclusively breastfeeds their infant prior to participation in the study
• Is willing to pump and store breastmilk for feeding her infant for a minimum of 48 hours in advance of study initiation and discontinue breastfeeding their infant for the duration of their study participation (beginning from time of dosing with BMT) and a minimum of 24 hours following the Safety Follow-Up visit (i.e., a minimum of 48 hours following dosing with BMT).
• Ensure at the time of screening that the breastfed infant can feed from a bottle during maternal participation in the study
• The subject is not pregnant, and does not intend to become pregnant before, during, or within 1 complete menstrual cycle or 2 months after administration of study drug
• Subjects of childbearing potential who are sexually active with a nonsterilized male partner must have stable, continuous use of an acceptable method of contraception throughout the duration of the study, and for at least 60 days after the dose of study drug

Exclusion Criteria (Main Criteria):

• Breastfeeding is not well established in the mother-infant pair (e.g., poor latching of the infant or low milk supply).
• Any condition that interferes with the successful collection of milk from one or both breasts including but not limited to lactation mastitis (typically presents as a tender, hot, swollen area of the breast that may or may not involve an infection), milk blister that may present as a blocked nipple pore, breast abscess, etc.
• Has used any investigational compound and/or an experimental medical device within 28 days before Screening.
• Has taken BMT within 24 hours of participation in the study

Lactating mother