Hair loss medicines and what the evidence shows

The European S3 guideline assessed the evidence for each option and turned it into recommendations for men and women^[1]. The 2017 Japanese guideline lists finasteride, dutasteride and 5% minoxidil solution as first-line treatments for men, and 1% minoxidil solution for women. It states that finasteride and dutasteride tablets are contraindicated for female pattern hair loss^[2].

Sources for the table: minoxidil foam in women^[3], minoxidil tablets versus solution^[4], side effects of low-dose tablets in 1,404 patients^[5], finasteride^[6], dutasteride^[7], spironolactone^[8], side effects of spironolactone tablets^[9] and the AAD page on female pattern hair loss (checked 2026-10-18).

Minoxidil on the scalp is the standard option for both sexes. Oral minoxidil is off-label for hair loss: the tablet was developed as a blood pressure medicine, and using it for hair is a prescriber’s decision based on your health and your other medicines.

Interest in the tablet has grown. A randomised trial in 90 men compared a 5 mg minoxidil tablet once a day with 5% solution twice a day. After 24 weeks the tablet was not superior overall, although photo assessment favoured it on the crown. Almost half of the men on the 5 mg tablet (49%) had extra body or facial hair^[4]. A separate retrospective study followed 1,404 patients on low doses, two-thirds of them women. Systemic side effects were uncommon and led 1.2% to stop treatment; 1.7% stopped because of any side effect, and no life-threatening effects were seen^[5]. Guidance still differs: the 2017 Japanese guideline advised against oral minoxidil^[2].

Both lower dihydrotestosterone (DHT), the hormone that shrinks follicles in pattern hair loss. In two one-year trials of 1,553 men, finasteride improved hair count, photos and the men’s own assessments, while men on placebo kept losing hair^[6]. Propecia, the finasteride tablet marketed for male pattern hair loss, received US FDA approval in December 1997, according to the FDA compounding risk alert (checked 2026-10-18).

Dutasteride blocks both forms of the enzyme. In a trial of 917 men, dutasteride 0.5 mg increased hair count and width more than finasteride 1 mg after 24 weeks, with similar side effects^[7]. A finasteride spray is another route: in a trial of 458 men it increased hair count more than placebo (20.2 versus 6.7 hairs) with blood levels of the drug more than 100 times lower than the tablet^[10]. The FDA says it has not approved any topical finasteride, and it received 32 adverse event reports for compounded versions between 2019 and 2024.

A meta-analysis of 15 placebo-controlled trials (4,495 men) found a 1.57-fold risk of sexual dysfunction with these medicines: 1.66 for finasteride, and 1.37 for dutasteride, which was not statistically significant^[11]. The FDA’s alert on compounded topical finasteride lists erectile dysfunction, lower libido, anxiety, depression, suicidal thoughts, brain fog and insomnia among reported events, and most of those reports said symptoms continued after stopping.

Minoxidil is the first-line medicine for women. Guidance on finasteride and dutasteride differs. The NHS states that women should not use finasteride, and the Japanese guideline lists both as contraindicated for female pattern hair loss^[2]. The American Academy of Dermatology notes that dermatologists may prescribe them off-label for some women, and that no prescription hair loss tablet is an option during pregnancy or when planning one, because these medicines may cause birth defects (both checked 2026-10-18). Spironolactone and low-dose minoxidil tablets are other options a doctor may add. See female pattern hair loss for the evidence in women.

Expect months rather than weeks. Trials judged results after 24 weeks to two years^[6][7], so a fair review of a new medicine comes after about six months. The NHS notes that these treatments work only while they are used, so hair loss usually resumes after stopping.

Yes, after a consultation. In Korea a clinic usually issues a prescription that you fill at a pharmacy (약국, yakguk) nearby. Finasteride and dutasteride are prescription medicines in Korea. The doctor decides how many weeks of supply to give.

Check the rules of the country you are going back to. Japan’s Ministry of Health, Labour and Welfare allows travellers to bring up to one month’s supply of prescription medicine for personal use; more requires an Import Confirmation obtained before leaving home (MHLW guidance, checked 2026-10-18). Travel planning is covered in treatment on a short trip.