Triiodothyronine (T3) is the ultimate form made from the binding monojodotyrosine and diiodotyrosine, which production is regulated by the pituitary acting on the basis of the so-called. feedback (re-synthesize T3 to form iodotyrosine), thyroid gland causing intensification of metabolism and protein anabolism and participating in lipolysis. It affects the level of serotonin from the brain, improving overall mood and preventing depressions.