What you need to know about finasteride

man looking at hair line
April 22, 2020

What you need to know about finasteride

Androgenetic alopecia, male pattern hair loss, MPHL, balding. Whatever you call it, losing your hair can be less than ideal, so what can you actually do about it? 

One tried and tested option available is finasteride. To understand how finasteride works, first we need to understand a little about male pattern hair loss. Hair loss results from the miniaturization of hair follicles over time, particularly in the vertex, anterior/ mid, frontal and temporal regions of the scalp. This may start in your 20s, and becomes more common with age. Over time, unfortunately, hair may become permanently lost. Different men experience hair loss at different ages and different parts of their head partially due to genetics, and partially due to their body’s production and distribution of DHT. 

Dihydrotestosterone, or DHT, increases balding in the scalp; men with hair loss have more DHT in the balding part of their scalp compared to other areas of the scalp. The male body converts testosterone to DHT via the enzyme 5-alpha reductase. Finasteride is an inhibitor of 5 alpha-reductase, and therefore works by blocking the conversion of testosterone to DHT. 

Studies have shown the ability of finasteride to lower bald scalp DHT levels to similar levels of a “hairy scalp”, and therefore function as an effective tool in the treatment of hair loss. Many methods, including photographic assessments as well as DHT and testosterone concentrations derived from analysing hair and scalp samples, have been utilised to compare the effects of finasteride compared to placebo treatments. These studies utilised a double-blind protocol, meaning both the researchers and the participants are unaware whether they are receiving a placebo or  finasteride treatment. Consistently, researchers have revealed finasteride’s effectiveness in reducing DHT levels and therefore protecting men against further hair loss. 

The general consensus is finasteride should be used to reliably prevent further hair loss- some researchers definitely think there is a chance it can lead to some increased growth, but it’s best to rely on finasteride as an effective preventative measure.  

Things you should know…

It is important to know that finasteride should not be handled by pregnant women.

Some men experience negative sexual function side effects after taking finasteride - this may include decreased libido, ejaculation disorder or erectile dysfunction; talk to your doctor if you think you may be experiencing any of these symptoms. Generally, finasteride has a good tolerability profile. 

Finasteride has been shown to be effective and safe in clinical trials up to 5 years.


  • Eur J Dermatol. 2002 Jan-Feb; 12(1): 38-49        Long-term (5-year) multinational experience with finasteride 1 mg in the treatment of men with androgenetic alopecia. https://www.ncbi.nlm.nih.gov/pubmed/11809594
  • McClellan KJ, Markham A. (1999). Finasteride: a review of its use in male pattern hair loss. Drugs, 57(1), pp. 111-26.     https://www.ncbi.nlm.nih.gov/pubmed/9951956
  • Ryu, H.K., Kim, K.M., Yoo, E.A., Sima, W.Y. and Chung, B.C. (2006). Evaluation of androgens in the scalp hair and plasma of patients with male-pattern baldness before and after finasteride administration. British Journal of Dermatology, 154(4), pp. 730-744.  https://www.ncbi.nlm.nih.gov/pubmed/16536818
  • Olsen, E. A., Whiting, D.A., Savin, R., Rodgers, A., Johnson-Levonas, A.O., Round, E., Rotonda, J. and Kaufman, K.D. (2012). Global photographic assessment of men aged 18 to 60 years with male pattern hair loss receiving finasteride 1 mg or placebo. Journal of the American Academy of Dermatology, 67(3), pp. 379-386. https://www.ncbi.nlm.nih.gov/pubmed/22325459
  • Dallob, A.L., Sadick, N.S., Unger, W., Lipert, S., Geissler, L.A., Gregoire, S.L., Nguyen, H.H., Moore, E.C. and Tanaka, W.K. (1994). The Effect of Finasteride, a 5a-Reductase Inhibitor on Scalp Skin Testosterone and Dihydrotestosterone Concentrations in Patients with Male Pattern Baldness. Journal of Clinical Endocrinology and Metabolism, 79(3), pp. 703-736.     https://www.ncbi.nlm.nih.gov/pubmed/8077349
  • Ustuner, E.T. (2013). Cause of Androgenic Alopecia: Crux of the Matter. Plast Reconstr Surg Glob Open, 1(7).      https://www.ncbi.nlm.nih.gov/pubmed/25289259
  • https://www.nps.org.au/medicine-finder/finasteride-1mg-tablets

Research over.
Time for action.