Hair Loss: Finasteride, Laser Light or Minoxidil - What Will Really Help Men & Women Regrow Lost Scalp Hair?

Men may be at a higher risk, but androge-netic hair loss is not a male exclusive.

Minoxidil, Finasteride, and low-level laser light therapy are Food and Drug Administration-approved/-cleared treatments for androgenetic alopecia, but do they actually work? That was one of the questions Areej Adil and Marshall Godwin tried to answer in a recent review; a systematic review and meta-analysis the scientists from the Memorial University of Newfoundland published in the Journal of the American Acadamy of Dermatology very recently and a paper of which its authors claim that I will clear up the confusion about the seemingly conflicting results of individual studies.
For their paper, Adil and Godwin searched the usual suspect databases, i.e. PubMed, Embase, and Cochrane including all relevant articles that were published before or in December 2016, with no lower limit on the year. Included were only randomized controlled trials (RCT) of "good or fair quality based on the US Preventive Services Task Force quality assessment process" (Adil 2017). The initial search produced a list of 45 articles of which 22 were excluded.

The "Norwood-Hamilton" classification is used to qualify the degree and type of hair loss. IIIa-V is the type subjects in most studies in this meta-analysis had. If you have hair loss and want some hints that may help you identify the type and cause of losing hair, check out this free article in the American Family Physician.

Eventually, the scientists' insights into the efficacy of nonsurgical treatments of androgenetic alopecia in comparison to placebo for improving hair density, thickness, growth were thus based on 23 papers - and 24 interventions.

• 4 studies on minoxidil 5% in men
• 5 studies on minoxidil 2% in men
• 5 studies on minoxidil 2% in women
• 3 studies on low-level laser light (LLLLT)
• 4 studies on finasteride 

Based on this dataset Adil et al. conducted a separate meta-analysis for 5 groups of studies that tested the following hair loss treatments: low-level laser light therapy in men, 5% minoxidil in men, 2% minoxidil in men, 1 mg finasteride in men, and 2% minoxidil in women.
All treatments were superior to placebo (P < 00001) in the 5 meta-analyses. Other treatments were not included because the appropriate data were lacking.

Figure 2: The meta-analysis confirms the efficacy of each and every of the treatments (Adil 2017).

The meta-analysis main message is: these treatments actually work. Or, to say in the scientists' own words:  "all treatments were superior to placebo (P < 00001)" (Adil 2017). In that, it should be obvious that the majority of studies investigating treatments for androgenetic alopecia were done in men. However, with the ever-increasing number of women (both obese and normal-weight) suffering from PCOS, it is particularly interesting to see that the over-the-counter minoxidil solutions (for women those are usually dosed at "only" 2%) are similarly effective as the high(er)-dose treatments for men.

How much hair can you expect to regrow?

For women Adil et al. (2017) report an average increase in hair growth amounted to 112.41 hairs/cm² in response to 2% minoxidil (vs. placebo). For men, the treatments that showed a mean difference in hair count listed from highest to lowest for men are

• finasteride 1 mg daily - 18.37 hairs/cm²,
• low-level laser light therapy (LLLLT) - 17.66 hairs/cm², 
• 5% minoxidil twice daily - 14.94 hairs/cm², 
• 2% minoxidil twice daily - 8.11 hairs/cm², and
• platelet rich plasma injections (3 months post) - 27.6 hairs/cm² (see bottom line)

In view of its - in some cases - extreme systemic (side) effects and considering the fact that it was the only treatment in which the scientists observed a significant heterogeneity (I² = 91%; P < 0.001 | note: I² statistic describes the percentage of variation across studies that is not due to chance), I would clearly recommend you stay away from finasteride until you've tried all the other venues.

Addendum: Using platelet-rich plasma as a "one-time" treatment alternative

Figure 3: Scalp of 29-year old at baseline (left) and 3 months (right) after treatment w/ PRP (Gkini 2014).

Studies investigating the effects of platelet-rich plasma injections, such as Gkini et al. (2014), found significant increases in hair growth after only three treatment sessions that were performed with an interval of 21 days. The unfortunate truth, however, is that, after a peak at 3 months (see photo on the right for a visual of the results in a 29-year old man | +27.6 hairs/cm²), the hair density started declining again and a single "booster session" after 6 months alone only slowed that decline, it didn't reverse it. Accordingly, it would seem as if you'd have to undergo the procedure thrice a year to get optimal results.

Speaking of which: Other studies confirm the observations Gkini et al. made, reporting an average increase of 28.37 hairs/cm² (45.9 hairs/cm², 12.3 hairs/cm² and 27.7 hairs/cm² in Gentile 2015; Kang 2009 and Cervelli 2014, respectively).

Quite impressive, but, with an average cost of $300-$500 per session, i.e. $900-$1500 for a single treatment, not exactly cheap (make sure the PRP for the is produced from your blood according to a standardized procedure - Gentile et al. for example combined PRP they extracted using the Cascade-Selphyl-Esforax system and PRP extracted according to the P.R.L. Platelet Rich Lipotransfert system).
References:

• Adil, Areej, and Marshall Godwin. "The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis." Journal of the American Academy of Dermatology (2017).
• Cervelli, V., et al. "The effect of autologous activated platelet rich plasma (AA-PRP) injection on pattern hair loss: clinical and histomorphometric evaluation." BioMed research international 2014 (2014).
• Dressler, Corinna, et al. "Efficacy of topical caffeine in male androgenetic alopecia." JDDG: Journal der Deutschen Dermatologischen Gesellschaft 15.7 (2017): 734-741.
• Finner, Andreas M. "Nutrition and hair: deficiencies and supplements." Dermatologic clinics 31.1 (2013): 167-172.
• Gentile, Pietro, et al. "The effect of platelet‐rich plasma in hair regrowth: a randomized placebo‐controlled trial." Stem cells translational medicine 4.11 (2015): 1317-1323.
• Gkini, Maria-Angeliki, et al. "Study of platelet-rich plasma injections in the treatment of androgenetic alopecia through an one-year period." Journal of cutaneous and aesthetic surgery 7.4 (2014): 213.
• Kang, J‐S., et al. "The effect of CD34+ cell‐containing autologous platelet‐rich plasma injection on pattern hair loss: a preliminary study." Journal of the European Academy of Dermatology and Venereology 28.1 (2014): 72-79.
• Leavitt, Matt, et al. "HairMax LaserComb® laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial." Clinical drug investigation 29.5 (2009): 283.
• Rushton, D. H. "Nutritional factors and hair loss." Clinical and experimental dermatology 27.5 (2002): 396-404.