1. Androgenetic Alopecia
Finasteride has been shown to be effective against androgenetic alopecia. Literature suggests this drug improves hair loss by 30% within six months of therapy [2]. Although it is effective, its systemic use causes various side effects, such as gynecomastia, decreased ejaculate volume, male infertility and high-grade prostate cancer. This limits the long-term utilization of the medicine.
Alternatively, topical finasteride show better results for androgenetic alopecia with more favorable side effect profile than systemic therapy. A systemic review concludes that topical finasteride decreases the rate of hair loss and increases total and terminal hair count. Furthermore, it has been shown to effectively reduce the concentration of DHT in both scalp and plasma [3].
Finasteride has also been explored for the female pattern baldness but it didn’t produce any significant results [4]. Moreover, one study was conducted to look at the effect of 5α reductase enzyme inhibitor, finasteride, on androgenic alopecia in female-to-male transgender patients. All the patients who took one 1 mg oral finasteride improved one grade on the Norwood-Hamilton scale after 4-6 months of initiating therapy [5].
2. Central Serous Chorioretinopathy
Central serous Chorioretinopathy (CSC) is an idiopathic disorder characterized by the accumulation of fluid behind the retina causing serous detachment of the macula, resulting in impaired vision. It has been proposed that elevated testosterone levels are associated with the pathogenesis of CSC. Research suggests that 5α reductase enzyme inhibitor, which prevents the conversion of testosterone into dihydrotestosterone, might be effective for treating CSC [6].
One study was designed to evaluate the safety and effectiveness of finasteride in patients with CSC. It found that patients who took finasteride for CSC reported improvement in visual activity. Furthermore, a reduction in macular thickness and subretinal fluid was observed, suggesting the efficacy of finasteride in treating this disorder [7].
3. Prostate cancer
Androgens play a key role in the pathophysiology of prostate cancer. 5α reductase inhibitors, including finasteride, prevent the formation of primary androgen (dihydrotestosterone) in prostate tissues. They might prove effective in treating or preventing prostate cancer.
A study named Prostate Cancer Prevention Trial (PCPT) was designed to study the effect of finasteride on prostate cancer. Almost 19,000 men aged 50 or older having PSA levels of 3ng or lower were enrolled. The subjects were randomly assigned to receive either 5 mg finasteride or an equivalent placebo once a day for seven days. The researchers found that finasteride delays or prevents the occurrence of prostate cancer [8].
Interestingly, it was observed that high-grade tumors were more prevalent in the treatment group as compared to the placebo group [8]. Later, it was suggested that it might be due to finasteride’s impact on prostate volume and its potential to suppress low-grade cancer rather than its effect on tumor morphology. Furthermore, the high-grade tumors were detected earlier and were less extensive in the treatment group as compared to the control group [9].
4. Hirsutism
Hirsutism is a condition characterized by excessive growth of the body and facial hairs. It is often associated with high levels of androgens. Finasteride may benefit people with hirsutism. A study was conducted to check the impact of 5α-reductase inhibitors on hirsutism in women with PCOS. Subjects enrolled in the study were administered with a placebo or finasteride once a day for seven months. The results found that finasteride produced a reduction in hirsutism score and was found to be well tolerated and effective [10].
