The aim of the present study was to examine the effect of prolonged use of finasteride on serum levels of dihydrotestosterone (DHT), estradiol (E2), progesterone, testosterone and androstenedione in women during the menstrual period. Further, to screen and compare the 5α-reductase activities through the expression of SRD5A1, SRD5A2 and AR gene and to determine the level of VEGF, VKOR and SAA gene expression and DNA damage. A total of 30 Saudi women aged between 25 to 35 years were enrolled in the study. The selected women were divided into two groups. The first group (n=15) received 5 mg finasteride/day for prolonged period of one year and second group (n=15) was taken as a healthy control. ELISA technique was used for measuring the serum levels of the targeted hormones and Comet assay was used for checking the DNA integrity.Our findings revealed significant decrement of DHT, E2, p sterone and androstenedione levels and elevated levels of testosterone in group treated with daily oral doses of 5 mg finasteride/day compared to the control subjects. mRNA expression suggested that finasteride has concrete effects on the gene expression of the selected genes from the treated group in comparison to the control group. In addition, finasteride induced DNA damage and heavy menstrual bleeding was noted in women treated with finasteride. In conclusion, the present findings revealed that finasteride has adverse health effects in women associated with gonadal sex steroids alterations, DNA damage and heavy menstrual bleeding with no consensus in treatment of androgenetic alopecia in women.