At first, they stimulate LH production so that testicles produce MORE T but eventually, the constant stimulation of LH stops its production, thus resulting in testicles no longer producing T. Some other anti-androgens only block T (bicalutamide, flutamide), others block it and reduce it through various mechanisms (spiro, cyproterone acetate) and some reduce its conversion to DHT (finasteride, dutasteride).