How does hormone therapy work?

[Other life style]

NOTICE -
The material presented in this document is presented strictly for educational purposes only! Because of the inherent risks associated with cross-gender hormone therapy, it is in the best interests of those considering such treatment to do so under medical supervision. This FAQ was prepared solely as a general primer for those seeking information on the subject and thus should not be treated as an authorative guide but rather as basis from which to conduct a informed dialog with your treatment provider.

How does hormone therapy work? -
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Essentually there are three types of naturally occurring hormones: Estrogens, progesterones, and testosterones. Females and males each have them in different ratios, but they are all present. Proportionally, females have more estrogens and progesterones, where as males more testosterones.
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The primary hormonal agents which cause the body to differentiate into female form and function are: Estrogens, which include natural and synthetic estradiols, estrones, and estriols that excite estrogenic receptors. And progesterones, which include synthetic progesterone analogues such as progestins, progestagens, and gestagens that excite progesteronic receptors.
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Various testosterones are collectively known as androgens. They excite androgenic receptors, causing the body to differentiate into male form and function. Natural and synthetic testosterones are generally referred to simply as androgens.
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Anti-hormones (typically in the form of anti-androgens) are useful in transsexual hormone therapy because they block hormone action or production. The basic mechanisms are:
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Androgen receptor antagonists which block the action of androgens at certain receptor sites.
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Androgen conversion inhibitors which block the conversion of one type of androgen to another.
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Gonadal androgen production inhibitors which suppress the pituitary signal that stimulates gonadal production of androgens.
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Adrenal androgen production inhibitors which directly suppress the adrenal production of androgens.
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Aggressive hormone therapy indirectly reduces gonadal hormone production by fooling the pituitary into thinking that there are plenty of hormones already in the body; consequently, the pituitary reduces the luteinizing hormone signals that stimulate the gonads thus reducing additional hormone production.
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Postnatally administered hormones as typically used in transsexual hormone therapy do not cause development of primary sex organs or genitalia (uterus, ovaries, vagina, testes, or penis) opposite those of birth. However, postnatal contrasexual hormone therapy does cause development of secondary sex characteristics in much the same manner as for the opposite gender.
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What effect does female hormone therapy have for the M-t-F transsexual? -
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The following effects have been observed in varying degrees, anywhere from slight to moderate, with extended treatment. High levels of estrogen will cause faster development up to a certain point, but generally do not create better results in the long term than more moderate treatment levels.
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Fertility decreases and sperm counts drop rapidly. Sometimes it will return to almost normal levels if hormonal treatments are discontinued within the first couple of months, but permanent sterility can occur in as little as six months. Estrogens, progesterone, progestins, and gonadal androgen production inhibitors are the chemicals primarily responsible for lowering fertility, although this should not be counted on for birth control since a slight sperm count can remain until the testes are surgically removed.
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Male sex drive decreases, spontaneous erections usually stop, and directly stimulated erections can become infrequent as well as difficult to maintain. Penile skin shrinks if erections are not regularly encouraged, testes and prostate atrophy, and semen secretion decreases usually resulting in less intense or unobtainable ejeculatory orgasms.
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Breast size increases. Typical growth is one to two cup sizes below closely related females (mother, sisters). The growth is not always symmetrical although neither is it for natal females. Sometimes the areoles and nipples swell, but generally not significantly, unless the body is less than a decade past puberty.
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Body fat is redistributed, tending to migrate away from the waist and toward the hips and bottom. The face becomes more typically female in shape.
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Body hair growth (not including head, face, or pubic area) usually slows, becomes less dense, and may lighten in color. Hair on the scalp may become thicker, and male pattern baldness generally stops advancing.
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In addition to those listed above the followings following effects are often reported although not supported by any specific medical literature available to us at the time this article was written:
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The metabolism decreases and if exercise is not increased, muscle tone is lost, especially from areas that were not well developed before hormone therapy began. Given a caloric intake and exercise regimen consistent with pre-hormonal treatment, one tends to gain weight, lose energy, need more sleep, and tend to become cold more easily.
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Outer skin layer becomes thinner, lending a finer translucent appearance and increased susceptibility to scratching and bruising. Tactile sensation may become more intense.
Oil and sweat glands become less active, resulting in dryer skin, scalp, and hair. Body odors (skin and urine) change, becoming less "tangy" or "metallic" and more "sweet" or "musky". Sometimes, tear glands also become less active, resulting in dryer eyes.
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Internal emotions are amplified, becoming more apparent, distinguishable, and influential. Some people report reduced anxiety and increased sense of well-being although this is likely a placebo effect. Changing the hormone therapy (adjusting dosages up or down in the regimen) sometimes causes short periods of depression or general moodiness.
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Female hormone therapy does not:
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Reduce facial hair growth significantly.
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Cause the voice to increase in pitch.
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Change the shape or size of bone structure. However, it may cause some slight loss of bone density.

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[Other life style]

How soon do these effects begin? -
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With effective and continuous dosages, most of the changes to which particular body is genetically prone will start within 2 to 4 months of entering therapy, becoming irreversible within 6 to 12 months, start beginning to level somewhat within 2 years, and be mostly done within approximately 5 years. The leveling generally takes longer if the testes are not removed. These timelines are of course generalizations based on what many have typically reported, but do not necessarily mean that everyone will find development, or reversibility, to be within these limits.
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What are the typical hormone treatment options? -
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The popular treatment combinations related to M-t-F hormone therapy are:
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Estrogen alone.
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Adding another type of estrogen.
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This may cause faster results for some people, but generally not better results in the long run.
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Adding an anti-androgen.
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Adding an anti-androgen may enable one to reduce the estrogen dosage while still obtaining acceptable development in a reasonable time frame, along with very similar results in the long run as opposed to a strictly high dose estrogen regimen. An anti-androgen fights the androgens remaining in the body by either by blocking the actions of androgens, or suppressing their production, rather than seeking to simply overwhelm them as is generally the case with strictly high dose estrogen treatments.
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Adding a progesterone.
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There is some indication that progesterone administered with estrogen may promote extra breast growth by increasing the volume of the lactation and ducting tissues. Some studies relating to birth control pills usage by natal females would seem to show that progesterones administered with estrogens reduce the risk of cancer from administration of estrogens alone. Yet, in some people, synthetic progesterones have a slightly androgenic effect and can apparently even antagonize estrogen absorption, although many believe that the use of non-synthetic progesterone may overcome this adverse effect and provide a healthier balance for an aggressive estrogen dosage.
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Note: Some endochrinologists seek to mimic a female menstrual cycle by decreasing or eliminating estrogen for one week of the month and/or adding or increasing progesterone for the same week. Generally this type of treatment is only preformed with patients who are also receiving anti-androgens so as to mitigate the effect of causing large variations in the endogenous androgen level. At this time we are not aware of any specific evidence that this type of treatment is either beneficial or harmful, although there are some indications that cycling progesterones may decrease the beneficial effect of estrogen on cardiovascular health, and may also promote extreme mood swings similar to PMS in natal females.
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How are these hormones administered? -
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Hormones are typically delivered by the following methods:
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Intramuscular injection
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Generally considered the safest and most efficient method, it is usually the least expensive option and causes less liver stress and clotting danger than oral delivery. The main disadvantages are pain and a slight infection risk from hypodermic needle usage. Sustained release intramuscular preparations (hormones suspended in oil) are recommended.
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Oral Delivery
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This is perhaps the most popular delivery method due to the convenience. Fairly steady hormone levels can be attained if divided into twice or thrice daily dosages. Athough there is a significantly increased stress on the liver since it has to process the hormones multiple times. Estrogen taken orally may also increase blood clotting factors and enhance the risk of thrombosis. Yet on the positive side, there are some indications that oral treatments are more beneficial for blood cholesterol levels than other methods.
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Suppositories
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Although perhaps one of the least popular methods, the rectal suppository is a most effective option if one can retain it long enough. Supplys a fairly steady hormone level which is perhaps 3 to 4 times as effective as oral delivery methods given the same weight (mg) of hormones.
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Transdermal patch or film
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Less liver stress and clotting danger than oral delivery. Steady hormone levels can be maintained if multiple patches are applied on staggered dates, although multiple simultaneous patches are typically required for pre-op dosages. Main disadvantages are inconvenience, skin irritation, and expense.
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Creams and Gels
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Absorption is variable depending on the preparation, and the nature of the skin it is applied to, yet also creates less liver stress and clotting danger than oral delivery. The main disadvantage is the low transfer rate into the body, too low to be effective unless it is very frequently rubbed on very large skin surfaces. Application to just the breast area does not limit the distribution to that area and the little estrogen absorbed is distributed throughout the body in insufficient quantity to make the breasts grow significantly. Generally the only obvious effect from this type of treatment is moister and healthier skin.
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Note: One should beware of non-prescription creams and gels from so called "transformation" outlets. If a preparation is not strong enough to require licensing, it is usually not strong enough to cause significant development either.

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