There is considerable controversy over the earliest age at which it is clinically, morally, and legally safe to use GnRH analogues, and for how long. The sixth edition of the World Professional Association for Transgender Health 's Standards of Care permit it from Tanner stage 2 but do not allow the addition of hormones until age 16, which could be five or more years later. Sex steroids have important functions in addition to their role in puberty, and some skeletal changes (such as increased height) that may be considered masculine are not hindered by GnRH analogues.
Early versus delayed treatment: For men who need (or will eventually need) hormone therapy, such as men whose PSA levels are rising after surgery or radiation or men with advanced prostate cancer who don’t yet have symptoms, it’s not always clear when it is best to start hormone treatment. Some doctors think that hormone therapy works better if it’s started as soon as possible, even if a man feels well and is not having any symptoms. Some studies have shown that hormone treatment may slow the disease down and perhaps even help men live longer.
Using appropriate tests for monitoring hormone therapy is crucial in establishing the appropriate dosing regimen. This reduces the chance of undesirable side effects and maximizes beneficial effects. For example, excessive use of androgens (testosterone, androstenedione, DHEA, and testosterone derivatives) can activate subclinical prostate tumors which are androgen-dependent. Monitoring is especially important in older males. By the age of 70, at least 50% of men have subclinical prostate cancer. These men are especially susceptible to prostate growth stimulation by androgens.