The side effects with dutaseride are not exactly random. Being healthy will reduce your chance of getting sides.
Dutasteride side effects (n= 8231)
Age, International Prostate Symptom Score, Body Mass Index, diabetes and glucose intolerance, but not serum testosterone or Total Prostate Volume, were significant independent predictors of sexual dysfunction. (1)
(1) Low serum testosterone levels are poor predictors of sexual dysfunction. 2010
There was another study that measured scalp DHT reduction (2) and got very different results. Which, to me, makes it questionable about the accuracy of measurement or it may mean that there is a large variation in people’s responses or something else.
The dusteride dose of 2.5-mg was better than the dutasteride dose of 0.5-mg at suppressing scalp DHT (79% vs 51%),
5 mg finasteride suppressed scalp DHT to a similar degree as 0.1 mg dutasteride group (41% and 32%, respectively).
The 2.5mg group had the highest satisfaction in scalp hair growth of 72% compared with 56% from 0.5mg.
There were no significant differences in total adverse events, serious adverse events, or withdrawals due to adverse events among any of the treatment groups, including placebo.
The only subject to develop gynecomastia was in the placebo group.
(2) The importance of dual 5a-reductase inhibition in the treatment of male pattern hair loss: Results of a randomized placebo-controlled study of dutasteride versus finasteride. 2006 (n=416)