Just an interesting observation, something I've been wondering for a while now, about Finasteride dosages. I recently read a few articles on pubmed about finasteride, tested among others on rats, and then compared it to humans.
Now, what surprises me is that at dosages of 51 mg/kg Finasteride on rats, it "only" gives a reduction in DHT values of a little less then 60 %, while in other studies on humans dosages at 1-5 mg give a reduction of around 70-80 % of DHT serum hormones. Physiologically, that just doesn't make any sense. The only thing that might perhaps explain this is that Finasteride was given to the rats in a suspension, perhaps this reduced the effect of Fina.
Any thoughts about my remarks here. Or anyone know more studies about different dosages of Finasteride tested on rats to compare with? I could only find one, you would think they would test the stuff a bit more on rats.
These are the articles mentioned:
- on rats with fina 51 mg/kg (DHT 59% lower)
http://endo.endojournals.org/cgi/reprint/136/4/1381.pdf
- on humans fina 5mg (DHT 73% lower)
http://jcem.endojournals.org/cgi/rap...jc.2006-2203v1
- on humans fina 1-5mg (DHT ca. 70-75% lower)
The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia.
Drake L, Hordinsky M, Fiedler V, Swinehart J, Unger WP, Cotterill PC, Thiboutot DM, Lowe N, Jacobson C, Whiting D, Stieglitz S, Kraus SJ, Griffin EI, Weiss D, Carrington P, Gencheff C, Cole GW, Pariser DM, Epstein ES, Tanaka W, Dallob A, Vandormael K, Geissler L, Waldstreicher J.
University of Oklahoma Health Sciences, Oklahoma City, USA.
BACKGROUND: Data suggest that androgenetic alopecia is a process dependent on dihydrotestosterone (DHT) and type 2 5alpha-reductase. Finasteride is a type 2 5alpha-reductase inhibitor that has been shown to slow further hair loss and improve hair growth in men with androgenetic alopecia. 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. CONCLUSION: In this study, doses of finasteride as low as 0.2 mg per day maximally decreased both scalp skin and serum DHT levels. These data support the rationale used to conduct clinical trials in men with male pattern hair loss at doses of finasteride between 0.2 and 5 mg.
Now, what surprises me is that at dosages of 51 mg/kg Finasteride on rats, it "only" gives a reduction in DHT values of a little less then 60 %, while in other studies on humans dosages at 1-5 mg give a reduction of around 70-80 % of DHT serum hormones. Physiologically, that just doesn't make any sense. The only thing that might perhaps explain this is that Finasteride was given to the rats in a suspension, perhaps this reduced the effect of Fina.
Any thoughts about my remarks here. Or anyone know more studies about different dosages of Finasteride tested on rats to compare with? I could only find one, you would think they would test the stuff a bit more on rats.
These are the articles mentioned:
- on rats with fina 51 mg/kg (DHT 59% lower)
http://endo.endojournals.org/cgi/reprint/136/4/1381.pdf
- on humans fina 5mg (DHT 73% lower)
http://jcem.endojournals.org/cgi/rap...jc.2006-2203v1
- on humans fina 1-5mg (DHT ca. 70-75% lower)
The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia.
Drake L, Hordinsky M, Fiedler V, Swinehart J, Unger WP, Cotterill PC, Thiboutot DM, Lowe N, Jacobson C, Whiting D, Stieglitz S, Kraus SJ, Griffin EI, Weiss D, Carrington P, Gencheff C, Cole GW, Pariser DM, Epstein ES, Tanaka W, Dallob A, Vandormael K, Geissler L, Waldstreicher J.
University of Oklahoma Health Sciences, Oklahoma City, USA.
BACKGROUND: Data suggest that androgenetic alopecia is a process dependent on dihydrotestosterone (DHT) and type 2 5alpha-reductase. Finasteride is a type 2 5alpha-reductase inhibitor that has been shown to slow further hair loss and improve hair growth in men with androgenetic alopecia. 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. CONCLUSION: In this study, doses of finasteride as low as 0.2 mg per day maximally decreased both scalp skin and serum DHT levels. These data support the rationale used to conduct clinical trials in men with male pattern hair loss at doses of finasteride between 0.2 and 5 mg.
