what are the effects of testosterone treatment?

Testosterone causes a variety of changes that happen to different extents and at different paces depending on the person, but the effects are more or lessly the same.

Things testosterone does (Permanently):
-Enlarges the clitoris (It's difficult to say how much, it really depends on the person, and the longer you take it the bigger it'll get but it stops growing eventually. It's also one of the first changes more people notice)
-Voice deepens
-Jawline and facial structure becomes more masculine.

Things testosterone does (That may revert if you ever stop taking T):
-Hair thickens and becomes more coarse
-More body hair/Facial hair (Reverts to some degree, depends on how long you took T and how long you've been off of it. Sometimes it goes away 100% sometimes note.)
-Fat redistribution to a more 'masculine' shape.
-Muscle is easier to gain.
-Menstral periods stop (May still experience spotting or stuff like that, takes a couple of months to kick in usually.)
-Oilier skin and increased acne
-Increased sex drive/Vaginal dryness

It's also good to note that testosterone will not make your breasts disappear or anything like that, basically the effects of T just cover or coat what you already have but what's there isn't really going to completely dissapear.

 

http://www.camh.ca/en/hospital/care_program_and_services/hospital_services/Documents/hormones-FTM.pdf