This is admittedly anecdotal but I had horrible frontal shedding on dutasteride until I added RU. I have read a lot of anecdotal reports of increase frontal shedding on dutasteride. Perhaps it is because the testosterone increase is greater than finasteride. Studies show that scalp testosterone rose 24% for Finasteride, 46% for 0.05mg Dutasteride, 44% for 0.1mg Dutasteride, 104% for 0.5mg Dutasteride. Now does that matter? I am not sure. Stolen from another forum user "If dutasteride increases scalp T more than finasteride, it's probably mostly to the extent that dutasteride prevents that T from becoming DHT to begin with. Keep in mind, you can sample sebaceous excretions. You can't sample the DP in vivo."
Perhaps it's throwing us into Telogen Effluvium because the hormone suppression is just so great.
It's hard to tell. I don't want to tell people to use a non FDA approved drug but I really believe I needed a topical AA on dutasteride.