@bjohnson511 to me it seems that any drug, or any dose of any drug, that is effective in reducing estrogen to below detectable levels, would have the same side effects. The letrozole insert does say that a 20% dose was effective. Rather than studying different, new drugs, I think it would be helpful to study the best dose, perhaps based on weight and age. But if effective, I would speculate that side effects will remain the same. Interested in hearing otherwise!