Background: Finasteride and dutasteride are inhibitors of the enzyme 5-alpha-reductase which inhibits the conversion of testosterone to dihydrotestosterone. Dutasteride inhibits both type I and type II 5-alpha-reductase while finasteride inhibits only the type II enzyme. As both isoenzymes are present in hair follicles, it is likely that dutasteride is more effective than finasteride. Aims: To compare the efficacy, safety and tolerability of dutasteride and finasteride in men with androgenetic alopecia. Methods: Men with androgenetic alopecia between 18 and 40 years of age were randomized to receive 0.5 mg dutasteride or 1 mg finasteride daily for 24 weeks. The primary efficacy variables were hair counts (thick and thin) in the target area from modified phototrichograms and global photography evaluation by blinded and non-blinded investigators. The secondary efficacy variable was subjective assessment using a preset questionnaire. Patients were assessed monthly for side effects. Results: Ninety men with androgenetic alopecia were recruited. The increase in total hair count per cm[2] representing new growth was significantly higher in dutasteride group (baseline- 223 hair; at 24 weeks- 246 hair) compared to finasteride group (baseline- 227 hair; at 24 weeks- 231 hair). The decrease in thin hair count per cm[2] suggestive of reversal of miniaturization was significantly higher in dutasteride group (baseline- 65 hair; at 24 weeks- 57 hair) compared to finasteride group (baseline- 67 hair; at 24 weeks- 66 hair). Both the groups showed a similar side effect profile with sexual dysfunction being the most common and reversible side effect. Limitations: Limitations include the short duration of the study (6 months), the small sample size and the fact that it was an open-label study. Conclusions: Dutasteride was shown to be more efficacious than finasteride and the side-effect profiles were comparable.