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06.06.2010


Testosterone enanthate works just as well when you take finasteride too

Testosterone enanthate

Finasteride
Testosterone enanthate injections build just as much muscle mass and power if you take finasteride at the same time [structural formulas shown below]. At least: they did in this study of over 65s who injected 200 mg testosterone once a fortnight. And before you ask: no, the researchers were not on the payroll of a pharmaceuticals company. They were paid by the American government.

Testosterone converts into the androgen DHT in the body. Many undesirable side effects of testosterone, such as acne, hair loss, increased aggression, an enlarged prostate and the increased chance of prostate cancer associated with this, are to a large extent the work of DHT.

The enzyme 5-alpha-reductase is responsible for converting testosterone into DHT. Finasteride blocks this enzyme. In test tube studies, DHT attaches better to the androgen receptor than testosterone. If you block 5-alpha-reductase with finasteride, is testosterone still anabolic? Yes, in animal studies. And in humans? That's the question these researchers wanted to answer.

So they gave 70 men, all of whom had a low T level, a placebo, testosterone enanthate, or testosterone enanthate plus 5g finasteride, for a period of three years. The figure below shows what happened to the muscle power, lean body mass and fat mass in the three groups.


Testosterone enanthate works just as well when you take finasteride too

Testosterone enanthate works just as well when you take finasteride too

Testosterone enanthate works just as well when you take finasteride too


We copied the table below from another publication by the same researchers, based on the same study. [J Clin Endocrinol Metab. 2004 Feb; 89(2): 503-10.]


Testosterone enanthate works just as well when you take finasteride too


Adding finasteride to the testosterone did not have a protective effect on the prostate. But this probably would have been the case if the men had taken higher doses of testosterone.

If less testosterone is converted into DHT, it would seem to be a reasonable assumption that more testosterone is being converted into estradiol. And, lo and behold, that's what happens after six months. The figure below is also from the 2004 study.


Testosterone enanthate works just as well when you take finasteride too


So chemical athletes who are worried about the androgenic effects of taking testosterone could use finasteride, you could conclude from the study. The addition of finasteride either does not reduce the muscle building effect of testosterone, or it only does so minimally. A possible downside for athletes, certainly if they take finasteride over an extended period of time, is that finasteride raises estradiol levels. And that increases the chance of developing gyno.

Source:
J Clin Endocrinol Metab. 2005 Mar; 90(3): 1502-10.