I previously wrote about dutasteride possibly being approved by the US FDA to treat hair loss in 2015. In August 2014, GlaxoSmithKline (GSK) published 6-month interim results from a Japanese clinical study of 120 male patients with androgenetic alopecia taking 0.5 mg of dutasteride daily. You can also download the findings by clicking on the Result Summary tab here and then clicking on the pdf link there.
It should be noted that all patients were Japanese and four patients withdrew from the trial. Key findings:
- 81 percent of patients saw at least some increase in vertex hair count (10 percent saw a great increase, 33 percent saw a moderate increase).
- 71 percent of patients saw at least some increase in frontal hair count (8 percent saw a great increase, 32 percent saw a moderate increase).
- Only one patient saw a decrease in vertex hair count, and only one patient saw a decrease in frontal hair count. It is not clear if this was the same patient. Both saw only a slight decrease.
(My note: For all intents and purposes, this implies that Dutasteride guarantees at the very least hair loss cessation after 6 months of use).
- 11 percent of patients reported erectile dysfunction as a side effect and slightly smaller percentages of patients reported decreased libido, ejaculation disorders and sexual dysfuntion.(My note: Since each patient can report more than one side effect, I am guessing that most of the 11 percent reporting erectile dysfunction also reported the other sexual side effects I listed above. However, the end of the pdf states that 38 percent of patients had side effects, which I think is an error as they are ignoring multiple side effect reports).
For 6 months, I found the hair loss related results slightly better than expected, but the side effects slightly worse than expected. I am assuming here that something like 15-20 percent of patients had side effects rather than 38 percent as reported, based on my assumption that multiple side effects on one person were reported individually (i.e., double, triple… counted) for some reason.
If 38 percent of patients really did get side effects, we will not see Dutasteride getting approved to treat hair loss in the US or Japan in my opinion.