Hair loss medicines:
what the trials show

Finasteride 1 mg: the longest controlled data

Two Phase III trials enrolled 1,553 men aged 18 to 41 with male pattern hair loss and randomized them to finasteride 1 mg a day or placebo for one year, and 1,215 of them continued in blinded extensions. Over five years, the placebo group kept losing hair. In a later analysis of the same men, finasteride 1 mg was associated with a 93% lower likelihood of further visible hair loss compared with placebo over 5 years (95% CI 89% to 97%).

A 10-year open-label study from Japan followed 523 men taking finasteride 1 mg daily. 91.5% were rated as improved and 99.1% as having no further progression. There was no placebo group, so this shows what happened on treatment, not what would have happened without it.

Dutasteride 0.5 mg: the strongest ranking, from indirect data

A network meta-analysis of 23 studies in men with androgenetic alopecia, published in JAMA Dermatology in 2022, ranked oral dutasteride 0.5 mg first for total hair count. At 24 weeks it was 7.1 hairs/cm² above oral finasteride 1 mg (95% CI 5.1 to 9.3). The authors combined trials that did not compare the drugs directly, so the ranking is an estimate, not a head-to-head result.

Topical finasteride: local action with less systemic exposure

The phase III trial of a topical finasteride spray enrolled 458 men with male pattern hair loss, with three arms: spray and placebo tablet, vehicle spray, and oral finasteride 1 mg. At 24 weeks, total hair count rose by 20.2 hairs on average with the spray versus 6.7 with placebo (P < 0.001). The authors report that the peak plasma finasteride level was more than 100 times lower with the topical form, and that serum DHT fell less (34.5% versus 55.6% with oral finasteride).

Minoxidil: oral and topical

Oral minoxidil has no long controlled trial in men with androgenetic alopecia, according to the network meta-analysis above. In that analysis, 2% topical minoxidil produced 8.5 hairs/cm² less than oral dutasteride at 24 weeks (95% CI 4.8 to 12.3).

For low-dose oral minoxidil, the largest safety series is a multicenter study of 1,404 patients across 10 centers in six countries. It is retrospective. Hypertrichosis was reported in 15.1% of patients, the overall adverse event rate was 20.6%, and systemic adverse events led to discontinuation in 1.2%. No life-threatening events were reported. A 2021 JAAD review of oral minoxidil found 17 studies with 634 patients, most in androgenetic alopecia, and called the drug well tolerated in healthy patients, while asking for larger randomized studies at different doses.

Time course: what the numbers can and cannot show

Most of the controlled data measure change at 24 to 48 weeks. Finasteride is the only one with five-year controlled data in this set. Results are measured while the medicine is taken; these trials do not measure what happens after stopping, and a result at one point in time is not a prediction for the next five years for one person.

Hair loss is also not only about the scalp. Trials measure hair count and photographs, and only some measure how people feel about their hair. A systematic review and meta-analysis from Leeds Beckett University, of 37 studies, found limited evidence of a severe effect on mental health and quality of life, with most studies showing a moderate impact at most, and it recommends screening with validated measures.

What this does not say

• These trials used brand or standard products at the studied doses. Our medicines are compounded or generic versions and were not tested in them.
• The Japanese 10-year figures come from a single-group study with no placebo, and the sample size is inconsistent in the record.
• Indirect comparisons in a network meta-analysis are estimates. Dutasteride and finasteride were not compared head to head in the pooled trials.
• Oral minoxidil data come largely from retrospective and small series. Side effects of finasteride are covered in our second article.

Sources

1. 1.Kaufman KD et al. Eur J Dermatol 2008;18(4):400-406 (PMID 18573712). Analysis of the two Phase III finasteride trials, five-year photographic assessment. PubMed
2. 2.Yanagisawa M et al. Long-term (10-year) efficacy of finasteride in 523 Japanese men with androgenetic alopecia. Clin Res Trials 2019. Clinical Research and Trials
3. 3.Gupta AK et al. Relative efficacy of minoxidil and the 5-alpha reductase inhibitors in androgenetic alopecia treatment of male patients: a network meta-analysis. JAMA Dermatol 2022;158(3):266-274. JAMA Dermatology
4. 4.Piraccini BM et al. Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial. J Eur Acad Dermatol Venereol 2022;36(2):286-294. JEADV
5. 5.Vañó-Galván S et al. Safety of low-dose oral minoxidil for hair loss: a multicenter study of 1404 patients. J Am Acad Dermatol 2021;84(6):1644-1651. JAAD
6. 6.Randolph M, Tosti A. Oral minoxidil treatment for hair loss: a review of efficacy and safety. J Am Acad Dermatol 2021. JAAD
7. 7.Rhodes T et al. Prevalence of male pattern hair loss in 18-49 year old men. Dermatol Surg 1998;24(12):1330-1332. Dermatologic Surgery
8. 8.Psychosocial impact of androgenetic alopecia on men: a systematic review and meta-analysis. Leeds Beckett University repository (eprint 9899). Leeds Beckett University