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Androgenetic alopecia (AA) is the most common hair loss condition that affects both men and women (1). Despite that, right now, there are only two medications approved by the FDA for hair loss treatment – topical minoxidil, for men and women, and finasteride 1mg tablet (Propecia®), for men (2).
Recently, the topical form of finasteride has been circulating in the market and is being sold as an alternative treatment option for androgenetic alopecia.
Even without FDA approval, can topical finasteride be considered effective, and should it be a part of your hair loss treatment regimen?
Finasteride for androgenetic alopecia – how does it work?
Firstly, it is important to understand how androgenetic alopecia causes hair loss.
Males and androgenetic alopecia
In males with androgenetic alopecia, the 5α-reductase enzyme converts testosterone to a more potent form, dihydrotestosterone (DHT). DHT is the androgen that causes hair miniaturization or the conversion of terminal hair with thicker, darker, and longer strands to miniaturized or vellus-like hair (see fig. 1)
Miniaturized hair strands are thinner, lighter, shorter, and shed easily. With that, inhibiting hair miniaturization is the goal in the management of androgenetic alopecia. This is achieved by inhibiting the enzyme that produces DHT. Hence a 5α-reductase inhibitor, such as finasteride, is the cornerstone of AA treatment.
Currently, finasteride 1 mg, a 5α-reductase inhibitor, is the only oral medication approved by the FDA to treat AA. It should be taken once a day for at least six months for noticeable improvement and further continued as maintenance (3). When the drug is discontinued, hair loss is expected to resume approximately 12 months after (2).
Females and androgenetic alopecia
It is worth noticing that females are experiencing hair loss due to androgenetic alopecia too. Unlike in males, female AA is not mainly dependent on androgen (testosterone) excess since most females who have AA do not have high androgen levels nor possess characteristic signs of androgen excess, like postmenopausal women (4,5).
Increased sensitivity of the hair follicles to androgens despite having normal levels also leads to hair miniaturization and loss (4).
Despite that, studies have shown that female pattern hair loss can be improved with the treatment of other anti-androgen systemic medicines like spironolactone and cyproterone acetate but not so much with oral finasteride (4).
Despite oral finasteride’s efficacy, topical finasteride has recently gained popularity, especially for males who do not want to take any systemic medications and for females with androgenetic alopecia whom oral finasteride is not indicated.
So in terms of efficacy, can topical finasteride be at par with its oral form?
Topical finasteride for androgenetic alopecia – does it work?
Topical finasteride vs. placebo
In 1997, the first clinical trial on topical finasteride as a treatment for male pattern baldness, which lasted for 16 months, was completed. In this study, a 0.005% finasteride solution applied twice a day was found to decrease the rate of hair loss compared to placebo with just six months of application.
Topical vs. oral finasteride
A study involving 45 male patients with AA was published in 2002. The subjects were divided into two treatment groups – finasteride 1% gel with placebo tablet and the finasteride 1mg tablet with the placebo gel.
The gels were applied twice daily, and the pills were taken once a day for six months. This study showed that increased terminal hair counts were seen after three months in the group that received the finasteride gel (+ oral placebo), while similar improvement was seen in the other group (oral finasteride + placebo gel) after just one month of treatment.
However, at the end of the treatment period, there was no significant difference between the two groups as all subjects experienced increased hair thickness, hair counts, and decreased bald areas (2,9). This study showed that, in terms of efficacy, topical finasteride had comparable results with oral finasteride.
Topical finasteride vs. topical spironolactone
In 2018, a study was conducted comparing the efficacy of topical finasteride with another anti-androgenic drug, spironolactone, in the management of both female and male pattern baldness.
Thirty-two subjects were divided into two groups. One group applied topical finasteride 0.1% solution while the other, spironolactone 5% solution for six months.
This study showed that both medications were good treatment options for AA. Furthermore, both spironolactone 5% and finasteride 0.1% topical solutions worked better on females compared to males with AA (10).
Topical finasteride for female androgenetic alopecia
Since it’s a multifactorial disease, different treatment modalities had been tried to manage female AA. In 2019, a study was conducted on 119 postmenopausal women with AA treated with formulations with either topical finasteride 0.5% and minoxidil 2% or 17β-estradiol 0.05% and minoxidil 2% once a day for 18 months.
This study showed that treatment with topical finasteride and minoxidil showed significant improvement and higher efficacy than 0.05% 17β-estradiol and minoxidil 2% solution (11).
In another study, the combination of topical finasteride 0.25% and minoxidil 3% solution showed significantly superior efficacy than minoxidil 3% alone in terms of increased hair diameter.
However, both solutions can increase hair density among postmenopausal women with AA after six months of treatment (12).
Topical finasteride for male androgenetic alopecia
In 2011, an aggressive multifaceted approach using topical and systemic medications for male AA was assessed. A formulation with finasteride, dutasteride, and minoxidil lotion (NuH Hair) was applied once a day and tested among males with AA (13).
The participants were also given the option to use all or any of the following with the NuH lotion:
It was instructed for ketoconazole shampoo to be scrubbed on the scalp for 100 seconds and the foam to be left on for 10 minutes before rinsing off. Aside from being an antifungal, ketoconazole can also inhibit a 5α-reductase.
The participants who used NuH Hair along with all medications noted significant hair growth within one month of treatment. Those who used NuH Hair alone reported significant improvement by three months. The authors of this pilot study concluded that aggressive management of AA leads to substantial and rapid hair growth.
Another study showed that the combination of 3% minoxidil with 0.1% finasteride lotion exhibited higher efficacy than 3% minoxidil alone based on global photographic assessment after six months of treatment for men with male pattern baldness (14).
In yet another study, topical finasteride 0.25% with minoxidil 3% solution had superior efficacy than minoxidil 3% alone for promoting hair growth among males with AA after six months of treatment (15).
A compounded formulation with minoxidil 10%, finasteride 0.1%, biotin 0.2%, and caffeine citrate 0.05% hydroalcoholic solution was used among five males with AA in the 2020 year study.
The participants were asked to apply the topical formulation twice daily for six months. After the treatment period, all participants had visually noticeable improvement of thicker and more voluminous hair with more scalp coverage (16).
Topical finasteride’s side-effects: Is it safer?
We are already familiar with side effects of oral finasteride like gynecomastia, breast tenderness, male breast cancer, decreased testicle size, testicle pain, sexual disorder, male infertility, and prostate cancer (2).
How about topical finasteride? Is it safer?
In a study, 18 males with AA received either finasteride 0.25% solution applied twice a day or finasteride 1mg tablet taken once a day. It was noted that both finasteride forms reduced plasma DHT in just seven days.
Hence, even the topical form of finasteride can reach the systemic circulation making it possible to cause side effects (17). The following side effects were noted among the participants:
In the second part of the study, 32 males with AA were treated with different doses of 0.025% topical finasteride. Among the different doses used, 100µL (0.2275mg) and 200µL (0.455mg) may be the most effective treatment regimen for AA since higher doses of 300µL and 400µL showed higher blood concentrations, thus increasing risks of possible side effects. The following side effects were documented in this study (18):
However, the same study compared how oral and different strengths of topical finasteride affected DHT levels in the scalp and serum. Lower levels are needed in the blood to reduce the chances of side effects.
DHT Reduction in Scalp and Serum (blood) / Oral vs. Topical finasteride
Figure 2 shows that even though 1 mg of oral finasteride still caused the greatest reduction of DHT in the scalp, comparable results can still be achieved with topical finasteride.
Furthermore, topical finasteride (0.1% and 0.025%) is less likely to cause side effects since its associated decrease in serum DHT is less compared to the oral form. The topical 0.25% finasteride, however, should be used with caution since it can still reduce serum DHT as with the oral form.
Topical finasteride in the market
Topical finasteride is relatively new in the market. As a result, only a few companies are currently producing it.
These companies may manufacture topical finasteride as a single medication or in combination with minoxidil. One of the popular sellers of topical finasteride is MinoxidilMax, which offers the following solutions:
|EssenGen-6 Plus||finasteride 0.05%, minoxidil 6%|
|Maxogen-X||finasteride 0.15%, minoxidil 7%, and other|
|DualGen-15||finasteride 0.1%, minoxidil 15%, and other|
Androgenetic alopecia is a debilitating psychosocial and chronic condition with no ultimate cure – continued medication is needed to stop progression and to achieve lasting results.
Finasteride 1mg/day, the only FDA-approved oral drug for male androgenetic alopecia, is proven to be effective. However, its potential side effects limit its preference, especially for long-term treatment.
Existing studies that prove the efficacy of topical finasteride make its use promising. I personally offer topical finasteride as an alternative, especially for those who have been using oral finasteride for a long time and refuse to continue it further.
After all, in the management of any disease, multiple treatment options and modalities should always be offered to patients to attain maximum efficacy and treatment compliance. As usual, its use has to be monitored by a dermatologist to detect possible side effects, if any.