The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis.
Topic: Hormone Therapy

Androgenetic alopecia, or male pattern hair loss, is a hair loss disorder mediated by dihydrotestosterone, the potent form of testosterone. Currently, minoxidil and finasteride are Food and Drug Administration (FDA)-approved, and HairMax LaserComb, which is FDA-cleared, are the only treatments recognized by the FDA as treatments of androgenetic alopecia.

PICO
Population: Patients with androgenetic alopecia
Intervention: Treatment with minoxidil, finasteride, or HairMax LaserComb
Comparison: Placebo or alternative treatments
Outcomes: Effectiveness of treatments for androgenetic alopecia

Included studies:
title: Topical minoxidil in early male pattern baldness.
abstract: One-hundred twenty-six healthy men with early male pattern baldness completed a 12-month double-blind, controlled trial of 2% and 3% topical minoxidil. Subjects were initially randomly assigned to use placebo or 2% or 3% topical minoxidil. After 4 months of study, the placebo group was crossed over to 3% topical minoxidil. Both objective measurement of hair growth by counting of vellus, terminal, and total hairs in a vertex target balding area and subjective assessment by subject and investigator were done. Treatment of subjects with topical minoxidil for 4 months resulted in a statistically significant increase in terminal hair growth in comparison with placebo therapy. In addition, subjects initially treated with placebo, when crossed over to topical minoxidil, showed a significant increase in the number of terminal hairs. No subject had a net hair loss in the target area during the study. These results indicate that topical minoxidil can increase terminal hair growth in early male pattern baldness.
title: Androgenetic alopecia: treatment results with topical minoxidil.
abstract: A double-blind 12-month trial was conducted to evaluate the safety and efficacy of topical minoxidil in patients with androgenetic alopecia. During the first 4 months of the study, patients applied a topical solution containing either 2% minoxidil, 3% minoxidil, or placebo to their scalps twice daily. At the end of the fourth month, patients taking placebo were crossed over to treatment with 3% minoxidil solution. Of 60 patients enrolled in the study, 43 were evaluable at month 12. Hairs were counted in a 1-inch target area and classified as vellus, indeterminate, and terminal; the latter two classifications were combined as nonvellus hairs for further statistical analysis. All three groups had significant increases in total, nonvellus, and terminal hair counts between baseline and month 4 and between month 4 and month 12. At month 4 the average total hair counts increased from a baseline mean of 158.2 to 270.2 in the 2% minoxidil group, from 156.6 to 287.0 in the 3% minoxidil group, and from 162.6 to 246.9 in the placebo group. At month 12 the means were 415.6, 448.5, and 471.1 in the 2% minoxidil, 3% minoxidil, and placebo-3% minoxidil crossover subjects, respectively. The increases from month 4 to month 12 were highly significant for each group (p = 0.0001). Average increases in nonvellus hair counts between months 4 and 12 were 216, 181, and 264 in the 2% minoxidil, 3% minoxidil, and placebo-to-3% minoxidil crossover groups, respectively, all highly significant differences from zero (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
title: Dose-response study of topical minoxidil in male pattern alopecia.
abstract: Fifty-eight men with Hamilton scale type III vertex or type IV male pattern baldness were studied to determine the dose-response activity of low concentrations of topical minoxidil in promoting hair growth. The patients were treated with topical minoxidil at doses of 0.01%, 0.1%, 1%, or 2% or placebo in a randomized double-blind design for 6 months. At the end of 6 months, patients using 0.1%, 1%, and 2% topical minoxidil solutions showed a significantly greater difference in the mean increase of nonvellus hair growth in comparison with those using 0.01% minoxidil or placebo. There was a clear dose-response correlation for the increase of nonvellus hairs in the 0.1%, 1%, and 2% minoxidil treatment groups. There was a statistically significant difference in patient's self-evaluation of overall hair growth and degree of decreased hair shedding in the 1% and 2% minoxidil groups when compared with the other study groups. From this study we conclude that significant increases in nonvellus hair counts occur with 0.1% and greater doses of minoxidil. However, only in patients treated with the 1% and 2% solutions of minoxidil was there clinically perceptible hair growth.
title: Finasteride in the treatment of men with frontal male pattern hair loss.
abstract: Finasteride, a specific inhibitor of type II 5alpha-reductase, decreases serum and scalp dihydrotestosterone and has been shown to be effective in men with vertex male pattern hair loss.
title: A randomized, placebo-controlled trial of 5% and 2% topical minoxidil solutions in the treatment of female pattern hair loss.
abstract: To pical minoxidil solution 2% stimulates new hair growth and helps stop the loss of hair in men with androgenetic alopecia and women with female pattern hair loss. Results can be variable, and historic experience suggests that higher concentrations of topical minoxidil may enhance efficacy.
title: The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: results of a randomized placebo-controlled study of dutasteride versus finasteride.
abstract: Male pattern hair loss (MPHL) is a potentially reversible condition in which dihydrotestosterone is an important etiologic factor.
title: Androgenetic alopecia in the female. Treatment with 2% topical minoxidil solution.
abstract: Women generally regard their hair loss as socially unacceptable and go to great measures to conceal their problem. In some cases, the negative self-image brought about by hair loss may be the basis of psychiatric illness. The purpose of this study was to evaluate a 2% topical minoxidil solution (Rogaine/Regaine, The Upjohn Co, Kalamazoo, Mich) for the treatment of female androgenetic alopecia. A 32-week, double-blind, placebo-controlled trial was conducted in 11 US centers. Three hundred eight women with androgenetic alopecia were enrolled. Two hundred fifty-six of these women completed the trial. A refined photographic technique was used to objectively determine the number of nonvellus hairs regrown.
title: A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men.
abstract: Topical minoxidil solution 2% stimulates new hair growth and helps stop the loss of hair in individuals with androgenetic alopecia (AGA). Results can be variable, and historical experience suggests that higher concentrations of topical minoxidil may enhance efficacy.
title: Efficacy, safety, and tolerability of dutasteride 0.5 mg once daily in male patients with male pattern hair loss: a randomized, double-blind, placebo-controlled, phase III study.
abstract: Dutasteride (Avodart) is a dual inhibitor of both type I and type II 5 alpha reductases, and thus inhibits conversion of testosterone to dihydrotestosterone, a key mediator of male pattern hair loss.
title: Topical minoxidil in the treatment of androgenetic alopecia in women.
abstract: Twenty-eight women with mild to moderate androgenetic alopecia were randomly assigned to apply either 2 percent topical minoxidil or placebo (vehicle) to their involved scalp areas twice daily. At the end of thirty-two weeks, there was a statistically significant increase of nonvellus target area hairs in the minoxidil-treated versus the vehicle-treated group (p = 0.006). Investigator assessment of moderate regrowth showed better results in subjects who used 2 percent topical minoxidil solution than those who used vehicle (p = 0.007), although subjects discerned no difference between treatment groups. Two percent topical minoxidil appears to be effective in the treatment of female androgenetic alopecia.
title: Treatment of female androgenetic alopecia with minoxidil 2%.
abstract: The safety and efficacy of minoxidil 2% for the treatment of female androgenetic alopecia was assessed in a 32-week double-blind placebo-controlled trial. Thirty-three women aged 22 to 44 years with hair loss classified as Ludwig's grade I or II were enrolled, and 28 completed the trial. Before the administration of treatment, mean nonvellus hair counts were taken within a 1-cm2 target area of the scalp. For the 15 patients in the minoxidil group, the mean count was 169 hairs compared with 161 hairs for the 13 patients in the placebo group. At the completion of the trial, the patients treated with minoxidil 2% had a mean nonvellus hair count of 195 hairs versus a mean hair count of 177 for patients in the placebo group; 60% (9) of the patients in the minoxidil group showed minimal to moderate hair growth compared with 46% (6) of the patients in the placebo group. No serious side effects were encountered during this study, nor any significant changes in safety parameters. There were no dropouts due to medical events related to minoxidil 2%.
title: The growth of human scalp hair mediated by visible red light laser and LED sources in males.
abstract: Low level laser therapy (LLLT) has been used to promote hair growth. A double-blind randomized controlled trial was undertaken to define the safety and physiologic effects of LLLT on males with androgenic alopecia.
title: Myosin-ATPase-activity and contractile properties after physical training.
title: Low-level light therapy for androgenetic alopecia: a 24-week, randomized, double-blind, sham device-controlled multicenter trial.
abstract: Androgenetic alopecia (AGA) is a common disorder affecting men and women. Finasteride and minoxidil are well-known, effective treatment methods, but patients who exhibit a poor response to these methods have no additional adequate treatment modalities.
title: Finasteride increases anagen hair in men with androgenetic alopecia.
abstract: The growth of scalp hair is a cyclical process of successive phases of growth (anagen) and rest (telogen). In previous clinical trials in men with androgenetic alopecia, treatment with finasteride increased scalp hair counts in a defined area (i.e. increased hair density).
title: HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial.
abstract: The use of low levels of visible or near infrared light for reducing pain, inflammation and oedema, promoting healing of wounds, deeper tissue and nerves, and preventing tissue damage has been known for almost 40 years since the invention of lasers. The HairMax LaserComb is a hand-held Class 3R lower level laser therapy device that contains a single laser module that emulates 9 beams at a wavelength of 655 nm (+/-5%). The device uses a technique of parting the user's hair by combs that are attached to the device. This improves delivery of distributed laser light to the scalp. The combs are designed so that each of the teeth on the combs aligns with a laser beam. By aligning the teeth with the laser beams, the hair can be parted and the laser energy delivered to the scalp of the user without obstruction by the individual hairs on the scalp. The primary aim of the study was to assess the safety and effectiveness of the HairMax LaserComb laser phototherapy device in the promotion of hair growth and in the cessation of hair loss in males diagnosed with androgenetic alopecia (AGA).
title: Finasteride improves male pattern hair loss in a randomized study in identical twins.
abstract: This study compared the efficacy of finasteride with placebo in the treatment of male pattern hair loss (androgenetic alopecia) in nine pairs of male identical twins.
title: Progression of hair loss in men with androgenetic alopecia (male pattern hair loss): long-term (5-year) controlled observational data in placebo-treated patients.
abstract: Relatively little is known about the progression of androgenetic alopecia (AGA; male pattern hair loss) in untreated men. We evaluated the long-term (5-year) progression of AGA in men treated with placebo in a controlled clinical trial setting. We analyzed pooled data over 5 years from two replicate studies with finasteride 1 mg/day in men with predominantly vertex-pattern AGA. Each study consisted of an initial 1-year, randomized, double-blind, placebo-controlled base study and four consecutive, 1-year, double-blind, placebo-controlled extension studies. Change over time in scalp hair growth was evaluated by four predefined endpoints: scalp hair counts; assessment of standardized clinical photographs by an expert panel; investigator clinical assessment; and patient self-assessment. All four predefined endpoints demonstrated progressive scalp hair loss in men receiving placebo over the 5-year study period, with a loss of 239 hairs from baseline (26.3% decline in hair density) measured in the target area at 5 years (p < 0.001 vs. baseline). Similarly, visible progression of scalp hair loss was demonstrated by global photographic assessment, with 75% of placebo patients rated as worsened from baseline at 5 years. We found that scalp hair loss continued in a progressive manner over a 5-year period in placebo-treated men with AGA.
title: Use of topical minoxidil therapy for androgenetic alopecia in women.
abstract: Androgenetic alopecia is the most common cause of hair loss in men and women. Androgenetic alopecia in women begins as a diffuse and progressive thinning of the frontoparietal area of the scalp. In women, hair loss at any age is socially unacceptable and may be the basis of psychiatric illness.
title: The effects of minoxidil, 1% pyrithione zinc and a combination of both on hair density: a randomized controlled trial.
abstract: Recent studies of antidandruff shampoos or tonics containing antifungal or antibacterial agents produced effects suggestive of a potential hair growth benefit.