Inclusion Criteria:
* Women aged between 21 and 65 years;
* Premenopausal or postmenopausal women may be included;
* May or may not be using female sex hormones (estrogen with or without progesterone, or their derivatives);
* Women who have previously had sexual experiences with orgasm, desire, and arousal, for a minimum period of two years;
* FSD, defined according to DSM-IV diagnostic criteria, that is, the presence of a persistent or recurrent inability to achieve or maintain adequate physiological sexual arousal during sexual activity, meaning a reduction or absence of genital response (lubrication, clitoral swelling, or other genital responses such as genital pleasure sensations);
* FSD causes significant personal distress and/or interpersonal difficulty;
* FSFI questionnaire meeting criteria for female sexual dysfunction, i.e., \<26.5;
* Stable relationship for more than 6 months, with a sexually active partner who is present (cannot be traveling, for example) during the treatment period;
* Ability to read and understand the Informed Consent Form (ICF) and to complete the questionnaires.
Exclusion Criteria:
* Women who do not agree to use a contraceptive method and who have the capacity to become pregnant during the study;
* Women who do not agree to attempt sexual activity at least twice a week while taking the study medication;
* Serious relationship problems, defined as a CSI-16 score below 51.5, of non-sexual origin, and which, in the investigator's opinion, may influence sexual activities;
* History of unresolved sexual trauma or abuse, that could interfere with participation or the results of the study;
* Diagnosis of vaginismus, genitopelvic pain/penetration disorder and/or sexual aversion disorder;
* Uncontrolled diabetes at screening visit (HbA1C \> 10%);
* Prior spinal cord injury, with lower limb paralysis;
* History of abdominal or pelvic surgery that may have damaged pelvic nerves, including vulvectomy, colostomy, cytostomy, hysterectomy, or bladder suspension;
* Current testosterone use, or long-term testosterone use (such as chip) within the past 6 months;
* Patients with severe current depression, characterized by the use or need for the use of psychotropic medications, including bupropion, lithium, or neuroleptics (patients using antidepressant medications such as selective serotonin reuptake inhibitors may participate);
* Presence of genital lesions that impair analysis of local adverse effects on the genitalia;
* Presence of diseases that cause excessive vaginal discharge, such as recurrent urinary tract infection, vaginal infection and pelvic inflammatory disease.
* Abnormal Papanicolaou test within the past 3 years;
* History of gynecological cancer (history of uterine dysplasia can be included, provided it has been properly treated for at least 6 months);
* History of pelvic irradiation;
* Use of topical medications in the genital region that may interfere with PSI assessment as well as their absorption or drug interaction, including vaginal estrogens, lubricants, spermicides, creams or gels, vaginal douches;
* History of symptomatic hypotension, or diseases that increase the risk of symptomatic hypotension, such as patient with heart disease (including history of angina and/or heart failure) and nephropathies;
* Current use of nitrates, such as propatylnitrate (Sustrate®), isosorbide (Monocordil®, Cincordil®, Isordil®), nitroglycerin (Nitradisc®, Nitroderm TTS®, Nitronal®, Tridil®) and isosorbitol dinitrate (Isocord®)
* ECG findings that are clinically symptomatic, or that, in the Investigator's judgment, are considered significant and pose a risk to the research volunteer's participation;
* Findings on laboratory tests that, in the Investigator's judgment, are considered significant and offer risk to the research volunteer's participation or may hinder the study analyses;
* TSH outside the normal range for age and/or participants with hypothyroidism who started thyroid hormone replacement less than 3 months ago, even if TSH is within normal limits;
* BP outside safe limits: SBP below 90 mmHg or above 170 mmHg; or DBP below 50 mmHg or above 100 mmHg, except for situations such as "white coat" syndrome;
* Severe hypertension, considered to be the use of three or more antihypertensive drugs;
* Diseases that can cause clitoral priapism, such as sickle cell anemia, multiple myeloma or leukemia;
* History of clitoral priapism;
* Current relevant diarrhea, defined as duration over four weeks, association with abdominal pain or malabsorptive syndrome, or presence of mucus, pus, or blood in the stool;
* Pregnant or lactating;
* Current use of nitric oxide donors, guanylate cyclase stimulators (e.g. Riociguat), or 5- phosphodiesterase inhibitors (Sildenafil, Tadalafil, etc.);
* Any disease or condition or physical finding that the Investigator considers significant and that increases the risk of the research participant's participation or may interfere with the results, including serious debilitating diseases, presence of cancer, serious mental illness, persistent abuse of medication;
* Partners with significant erectile dysfunction, defined as the inability to maintain an erection to provide satisfactory sexual intercourse in most sexual encounters;
* Having participated in the BZ371CLI601 study;
* Known hypersensitivity to BZ371A or any of the components of the formulation;
* Significant tobacco or alcohol abuse that, in the investigator's opinion, may impair the participant's sexual function (light or moderate use of tobacco or alcohol is permitted);
* Less than 3 valid sexual encounters, defined as a "yes" answer to question 7 of the FSEP, or use of less than 3 doses of PSI in the run-in period.
