This figure of a .5mg Dutasteride dose resulting in a 55% decrease in scalp DHT appears quite frequently. It tends to go something like this (from July of 05):
Bryan said:
Slartibartfast said:
sam said:
Dutasteride levels: 90% serem, 55% scalp
Finasteride equiv: 70% serem, 38% scalp.
I seem to remember Bryan talking about these figures and how another, contradictory study demonstrated that scalp and serum DHT levels decrease by broadly similar amounts - in percentage terms.
Exactly. Those specific numbers Sam quoted don't mean diddly-squat.
Bryan
Perhaps people should read the 55% figure for dutasteride in tandem with the 38% figure for finasteride (quoted above), as they presumably came from the same study. Yet in the case of Finasteride this research is more often quoted:
"The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia"
University of Oklahoma Health Sciences, Oklahoma City, USA.
...OBJECTIVE: We attempted to determine the effect of finasteride on scalp skin and serum androgens. METHODS: Men with androgenetic alopecia (N = 249) underwent scalp biopsies before and after receiving 0.01, 0.05, 0.2, 1, or 5 mg daily of finasteride or placebo for 42 days. RESULTS: Scalp skin DHT levels declined significantly by 13.0% with placebo and by 14.9%, 61.6%, 56. 5%, 64.1%, and 69.4% with 0.01, 0.05, 0.2, 1, and 5 mg doses of finasteride, respectively. Serum DHT levels declined significantly (P <.001) by 49.5%, 68.6%, 71.4%, and 72.2% in the 0.05, 0.2, 1, and 5 mg finasteride treatment groups, respectively."
It seems illogical to say that .5mg of dutasteride reduces serum DHT by significantly more than finasteride, yet lowers scalp DHT by significantly less than it. This is particularly strange given dutasteride's out-performance of finasteride in hair count studies and so I'll treat the 55% figure with some suspicion.
Slarti