Eligibility Criteria:
Inclusion Criteria:
* Written informed consent before starting any study related procedures;
* Men 18 to 40 years of age;
* Men with mild to moderate vertex male pattern hair loss according to a modified Norwood/Hamilton classification scale (III vertex, IV or V);
* Participants willing to have a tattoo in the target area;
* Outpatients;
* Ability to comprehend the full nature and purpose of the study, including possible risks and side effects;
* Ability to co-operate with the Investigator and to comply with the requirements of the entire study.
Exclusion Criteria:
* Clinically relevant abnormal skin scalp findings which could interfere with the aim of the study; in particular, abrasion, actinic keratosis, inflammatory disorders or any other abnormality;
* Participants who had had hair transplant surgery or hair weaving;
* Clinically relevant abnormal laboratory values indicative of physical illness;
* Ascertained or presumptive hypersensitivity to the active principle and/or formulations' ingredients; history of anaphylaxis to drugs or allergic reactions in general, which the Investigator considers may affect the outcome of the study;
* History of local infections of skin and subcutaneous tissues of the head in the 3-months period before the trial inclusion;
* Relevant history of renal, hepatic, gastrointestinal, cardiovascular, respiratory, skin, haematological, endocrine or neurological diseases, that may interfere with the aim of the study;
* Suspicion of malignancy, including prostate cancer;
* History of infertility or difficulty fathering children;
* Participants who wish to conceive children during the study or whose sexual partner(s) is pregnant;
* Participants with active seborrheic dermatitis;
* History of varicocele;
* Concurrent use of systemic corticosteroids, topical corticosteroids in the balding area studied, anabolic steroids, or over-the-counter "hair restorers";
* Use of the following drugs with antiandrogenic properties within 6 months of study entry: flutamide, cyproterone acetate, estrogen, progesterone, cimetidine, spironolactone or ketoconazole;
* Participants who had been treated with any of the following drugs within the past year: minoxidil (topical or oral), zidovudine, cyclosporine, diazoxide, phenytoin, systemic interferon, psoralens, streptomycin, penicillamine, benoxaprofen, tamoxifen, phenothiazines or cytotoxic agents;
* Use of finasteride or dutasteride within previous 12 months;
* Light or laser treatment of scalp within previous 3 months;
* Participation in the evaluation of any drug for 3 months before this study, calculated from the first day of the month following the last visit of the previous study;
* History of drug, alcohol \[\>2 drinks/day defined according to USDA Dietary Guidelines 2010\], caffeine (\>5 cups coffee/tea/day) or tobacco abuse (10 cigarettes/day).