Does spironolactone lower testosterone in men?

Probably yes... Most of the studies done seem to deal with females with high testosterone levels, but I would assume the same biochemical pathways would be applicable to males. If you are worried about total and free testosterone levels as a male, as well as serum estradiol, you may want to avoid this medication. Some of its effect may center around an increase in shbg or TBG which decreases free testosterone.