It is well known that testosterone (T) under the influence of 5α-reductase enzyme is converted to dihydrotestosterone (DHT), which causes androgen-dependent diseases. The aim of this study was to synthesize new dehydroepiandrosterone derivatives (3a-e, 4a-i, 6 and 7) having potential inhibitory activity against the 5α-reductase enzyme. This paper also reports the in vivo pharmacological effect of these steroidal molecules. The results from this study showed that all compounds exhibited low inhibitory activity for 5α-reductase type 1 and 2 enzymes and they failed to bind to the androgen receptor. Furthermore, in the in vivo experiment, steroids 3b, 4f, and 4 g showed comparable antiandrogenic activity to that of finasteride; only derivatives 4d and 7 produced a considerable decrease in the weight of the prostate gland of gonadectomized hamsters treated with (T). On the other hand, compounds 4a, f and h showed 100% inhibition of the growth of prostate cancer cell line PC-3, with compound 4 g having a 98.2% antiproliferative effect at 50 μM. The overall data indicated that these steroidal molecules, having an aromatic ester moiety at C-3 (4f-h), could have anticancer properties.