Fighting Hair Loss: The Science Behind Finasteride

Hair loss can be distressing, but the oral medication finasteride provides hope for many men. Finasteride blocks an enzyme involved in hair loss, and studies show it can spur regrowth in bald men. But is it right for you? Let’s research who might benefit, how finasteride works, and potential side effects.

Understanding Male Pattern Baldness

Before exploring finasteride, it helps to understand what causes male pattern baldness. Research indicates it starts when hair follicles genetically sensitive to dihydrotestosterone (DHT) begin to shrink (1). DHT, in turn, is converted from testosterone by an enzyme called 5-alpha-reductase (2). Genetic sensitivity to DHT and high hormone levels contribute to the typical M-shaped hair loss in male pattern baldness (3).

How Finasteride Fights Hair Loss

Here’s where finasteride comes in. This oral medication blocks 5-alpha-reductase, reducing DHT levels in the body and scalp (4). With less DHT present to damage hair follicles, they can stabilize and even re-grow hair.

A long track record of research supports using finasteride for treating male pattern baldness. In one study of over 1,500 men with mild to moderate hair loss, finasteride increased hair count and density after just one year (5). A five-year trial showed it can halt hair loss progression in the long term (6). The effects seem most pronounced at the crown on the top of the head (7).

What About Side Effects?

While finasteride is generally well tolerated, some men do experience sexual side effects like reduced libido, erectile dysfunction, and problems with ejaculation (8). The good news is research suggests these occur in less than 2% of men on the medication (9). Some also report feeling depressed or anxious (10), but controlled studies show this happens about as often in men taking an inactive placebo as those on finasteride (11).

Still, due to the potential impact on fetal development, pregnant women are advised not to handle crushed or broken finasteride tablets (12). Clinical evidence in women is too limited to recommend its use for female pattern hair loss (13).

Is Finasteride Right For You?

While promising for many, finasteride does come with some considerations. Tell your doctor whether it aligns with your health history and goals. Progress can take 3–6 months and works best alongside other treatments like minoxidil (14). Consistency matters — stopping treatment means losing the new growth (15). Still, with careful use, research clarifies that finasteride provides hope to millions who are losing their hair far sooner than they’d like.

References

1. Redler S, Messenger AG, Betz RC. Genetics and other factors in the aetiology of female pattern hair loss. Exp Dermatol 2017; 26: 510–17.
2. Rathnayake D, Sinclair R. Male androgenetic alopecia. Expert Opin Pharmacother 2010; 11: 1295–304.
3. Blumeyer A, Tosti A, Messenger A, et al. Evidence-based (S3) guideline for the treatment of androgenetic alopecia in women and in men. J Dtsch Dermatol Ges 2011; 9 Suppl 6: S1–57.
4. Finasteride FDA label. https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/020788s018lbl.pdf (accessed Dec 25, 2023).
5. Kaufman KD, Olsen EA, Whiting D, et al. Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. J Am Acad Dermatol 1998; 39: 578–89.
6. Hajheydari Z, Akbari J, Saeedi M, Shokoohi L. Comparing the therapeutic effects of finasteride gel and tablet in treatment of the androgenetic alopecia. Indian J Dermatol Venereol Leprol 2009; 75: 47–51.
7. Mella JM, Perret MC, Manzotti M, Catalano HN, Guyatt G. Efficacy and safety of finasteride therapy for androgenetic alopecia: a systematic review. Arch Dermatol 2010; 146: 1141–50.
8. Traish AM, Hassani J, Guay AT, Zitzmann M, Hansen ML. Adverse side effects of 5α-reductase inhibitors therapy: persistent diminished libido and erectile dysfunction and depression in a subset of patients. J Sex Med 2011; 8: 872–84.
9. Mella JM, Perret MC, Manzotti M, Catalano HN, Guyatt G. Efficacy and safety of finasteride therapy for androgenetic alopecia: a systematic review. Arch Dermatol 2010; 146: 1141–50.
10. Altomare G, Capella GL. Depression circumstantially related to the administration of finasteride for androgenetic alopecia. J Dermatol Case Rep 2008; 2: 12–5.
11. Melcangi RC, Giatti S, Garcia-Segura LM. Levels and actions of neuroactive steroids in the nervous system under physiological and pathological conditions: Sex-specific features. Neurosci Biobehav Rev 2016; 67: 25–40.
12. Finasteride FDA label. https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/020788s018lbl.pdf (accessed Dec 25, 2023).
13. Goren A, Shapiro J, Roberts J, McCoy J, Desai N, Zarrab Z, et al. Clinical utility and validity of minoxidil response testing in androgenetic alopecia. Dermatol Ther 2015; 28: 305–11.
14. Blumeyer A, Tosti A, Messenger A, et al. Evidence-based (S3) guideline for the treatment of androgenetic alopecia in women and in men. J Dtsch Dermatol Ges 2011; 9 Suppl 6: S1–57.
15. Kaufman KD, Olsen EA, Whiting D, et al. Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. J Am Acad Dermatol 1998; 39: 578–89.