Hormone replacement therapy (HRT) is, for many transgender people, an essential part of their overall transition plan. For male to female transgender people, it will typically involve lowering testosterone levels while introducing feminizing levels of estrogen and sometimes progesterone. By lowering the testosterone level, one of the major effects will be to stop any further development of male secondary sex characteristics. In most cases, starting an antiandrogen earlier in life can translate into a higher amount of passing privilege. If you start before puberty sets in, you can completely prevent any development of male secondary sex characteristics.
There are multiple strategies when it comes to effectively inhibiting testosterone production in a transgender woman. One of the most common strategies is to use an antiandrogen such as spironolactone or cyproterone acetate to block the Androgen Receptors (AR). These AR antagonists will bind with the androgen receptors which will prevent the testosterone from binding to them. If the testosterone is unable to bind to the ARs, then the cells will no longer activate the associated secondary male genes. This will stop further development of those characteristics. However, in most cases it will not reverse the body changes that have already occurred.
The second strategy is usually not employed unless the first approach is not reducing the testosterone levels enough. In that case, an Antigonadotropin such as leuprorelin or cetrorelix can be used. These drugs will suppress the gonadotropin-releasing hormone which in turn inhibits the release of gonadotropins. Without these gonadotropins, the testes cannot make testosterone which definitely drops the levels where they need to be. This is an extremely effective method for when AR antagonists just aren’t getting the job done. Of course, both of these strategies are reversible and if you stop taking whichever one you are on, it will result in a resumption of male secondary sex characteristics. Estrogen will also act as a antigonadotropin though it would require a much higher dose than is typically given to trans women and with that higher dose comes an increased blood clot risk.
The last strategy for reducing testosterone levels is the permanent option which is a surgery known as an orchidectomy. It is often referred to as a bilateral orchidectomy and with it, the surgeon surgically removes both testes which are the main testosterone producers in the body. Small amounts of testosterone are also produced in the adrenal glands by both men and women. After an orchidectomy, the trans woman will typically have a slightly lower testosterone level than a cis woman as women also produce small amounts of testosterone in their ovaries. The big disadvantage to an orchidectomy is that it, and the obvious sterility it results in, is permanent. One thing to be aware of is that after an orchidectomy you will experience hot flashes if you go off of your estrogen and if you are off of it for more than a year, bone density loss can occur.
An orchidectomy does have some really good benefits. The biggest benefit is not having to take an antiandrogen which can save you money and one less drug for your liver to process is not a bad thing at all. Often, your endocrinologist can lower your dosage of estrogen after an orchidectomy. In many cases, feminization can often occur a little faster which is a plus for transition. It can also help with your dysphoria and self esteem as you say goodbye to a pair of male parts. Physically, tucking becomes a lot easier and a lot less painful. One point that needs to be made is that if you do get an orchidectomy, make sure the surgeon leaves your scrotal sack in place as this is used for GRS. If that skin is missing, they will need to take it from somewhere else.