hi, i have a question about propecia that i cant seem to find in the archives– if propecia raises testosterone and DHT is a byproduct of testosterone, then wouldnt taking propecia in effect block DHT and also increase the chance that your body is producing more DHT from the increase in test.? also, you state that scalp itching is not a sign of mpb, yet i’ve read way too many instances of people with scalp itch and hair loss –do all these people have scalp problems that only seem to appear as soon as they start losing their hair?–thx for best hairloss blog on the net!!
Your question is confusing and I do not think you have the correct information. Propecia (finasteride 1mg) is a 5-alpha-reductase inhibitor which blocks the conversion of testosterone to dihydrotestosterone (DHT). The body often increases testosterone as a result, which implies some internal feedback loop may exist. Increases of testosterone levels by 18% have been reported, but the data on long term testosterone levels is not available with people on Propecia.
With regard to itching of the scalp with hair loss, this could be explained as an indirect effect of reduced hair volume, more drying, and certainly more sun exposure.
If you look at the flow diagram, you will see where testosterone fits into the overall cycle and that DHT is formed with the help of the enzyme 5-alpha reductase.
Graphic source: GentlePharmacy