Low dose oral minoxidil for the treatment of female pattern hair loss

Dear Editors,

Female pattern hair loss (FPHL), also known as androgenetic alopecia (AGA) is the most common form of hair loss, impacting both men and women. ¹ Although various treatment options exist, including topical minoxidil and oral finasteride, their efficacy in female AGA has been a subject of debate. ² Among these options, oral minoxidil at low doses has emerged as a potential alternative for women with AGA who do not respond adequately to topical therapies or are unable to tolerate systemic treatments such as finasteride. ³ , ⁴

In this context, we present a case involving a 63‐year‐old postmenopausal woman with FPHL who underwent a 3‐month regimen of 1.25 mg oral minoxidil daily. Prior to this, topical treatments with minoxidil and bimatoprost had been administered for a year without significant improvement in hair growth. ⁵ The patient declined systemic treatment with finasteride. Given the significant impact of her hair loss on her quality of life, low‐dose oral minoxidil (LDOM) was proposed as an alternative treatment option. Hair density documentation using TrichoScan technology, a computer‐assisted method for determining hair density, was performed before treatment start and after 3 months. In order to enable precise comparison of hair density measurements of the treated area, a marking point was tattooed on a briefly shaved area of the scalp (1 cm²) with an 18‐gauge cannula and sterile black ink. The main outcome measure revealed a hair number of 98 hairs per square centimeter before treatment start (Figure 1A) and 140 hairs per square centimeter after 3 months of LDOM (Figure 1B). Mean hair diameter (µm) was a little less after 3 months (104.25 µm vs. 89.81 µm), which could be related to a higher number of newly grown hair. As a side effect hair growth on the face has been observed.

FIGURE 1.

(A) Trichoscan measurement revealed a hair number of 98 hairs per square centimeter before treatment start. (B) Trichoscan measurement revealed a hair number of 140 hairs per square centimeter after 3 months of LDOM. LDOM, low dose oral minoxidil.

Our findings suggest a hair growth‐promoting effect of LDOM, consistent with results from several other studies. ³ , ⁴ , ⁶ , ⁷ , ⁸ The mechanism of action of minoxidil in AGA is not fully understood. However, minoxidil acts as a vasodilator by opening potassium channels, likely resulting in enhanced microcirculation and the induction of growth factors that stimulate hair growth. ⁴ While topical minoxidil solutions have demonstrated efficacy in various trials, limitations arise with their use. ⁹ Firstly, they necessitate twice‐daily topical application, which can be inconvenient for many patients. Secondly, several local side effects, such as a poor and messy hair texture, skin irritation, or contact dermatitis, may occur, posing compliance challenges. Although published studies have reported good tolerance of LDOM, concerns persist regarding potential serious adverse events associated with oral administration, particularly with higher doses of minoxidil. ¹⁰ Given the limited number of patients included in these trials, not all potential side effects may have been captured. Despite our observations suggesting the safety and efficacy of LDOM in our patient, caution is warranted when drawing definitive conclusions about its clinical efficacy and safety profile. Therefore, oral Minoxidil for its use in AGA needs further investigation in larger trials.

CONFLICT OF INTEREST STATEMENT

The author declares no conflicts of interest.

ETHICS STATEMENT

The patient in this manuscript has given written informed consent to publication of her case details.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.