Letro is an AI and will do nothing to reverse gyno.
You need a SERM to treat gyno, either nolvadex or raloxifene.
Gyno can take anywhere from a few weeks to over 9 months to treat depending how fibrous your lumps have become.
You would benefit form having blood work done when you cycle because if your estrogen is properly controlled with an AI you won't be getting gyno.
The negative health effects associated with high estrogen are far greater than gyno.
Stop Using Aromatase Inhibitors to Reverse gynecomastia! SERM's Only!