Glossary
The words that get used about hormones as if everyone already knows them. Some come from endocrinology, some from the lab sheet that comes back after a blood test, and some from forums, where half the vocabulary is drug names and the other half is shorthand. Each entry gives the plain meaning first, then where you will meet the word, what it means for you, the common questions, and which guide goes deeper.
A few entries matter more than the rest. Estradiol and the anti-androgens are the medicines most feminizing plans are built from. Peak and trough, SHBG and hematocrit are the words that make a blood result make sense, and worth understanding before anyone changes a dose because of one. How to read your hormone blood results puts them together.
The same medicine often goes by different names in different countries, and so does the same route in: informed consent in one place, a gender clinic referral in another. Where a term is used mainly in one country, the entry says so.
I add terms as they come up in the guides, so this list grows. If a word you have hit is not here, tell me and I will write it.
Terms A–Z
A
Androgen
Hormones such as testosterone and DHT that drive a testosterone-led puberty. Everyone makes some; what differs is how much, and how medicines lower or block them.
Anti-Androgen
A medicine that lowers testosterone or blocks its effect. Usually taken with estrogen; which one you get depends on where you live.
B
Bicalutamide
An anti-androgen that blocks testosterone's effect without lowering its level. Needs liver checks; less studied in trans people.
Bridging Prescription
Hormones prescribed by a GP while you wait for a gender clinic, as harm reduction. Mostly a UK term; whether a GP offers it varies.
C
Cyproterone Acetate
The usual anti-androgen outside the US. Very effective; now prescribed at lower doses because of meningioma risk, with prolactin and liver checks.
D
DVT (Deep Vein Thrombosis)
A blood clot in a deep vein. Estrogen raises the risk, oral more than patches or gel; smoking, surgery and long flights raise it most.
E
Endocrinologist
A doctor who specialises in hormones. Useful for complicated cases and part of some clinic routes; many people on HRT never need one.
Estradiol
The estrogen used in feminizing HRT, identical to the body's own. Comes as tablets, patches, gel, injections and implants; measured in pg/mL or pmol/L.
G
GnRH Agonist
An injection or implant that shuts down the body's own sex hormone production. A strong anti-androgen; expensive, and estrogen alongside it is essential.
H
Hematocrit
The percentage of your blood that is red cells. Testosterone raises it, so it is watched on every masculinizing blood test.
I
Informed Consent
Prescribing hormones after a thorough explanation of effects and risks, without requiring a psychological assessment first. The medical checks and monitoring stay the same.
M
Microdosing
Informal term for lower-dose hormones, usually for slower or partial change. It slows changes; it cannot choose which ones, and it is not contraception.
Monotherapy
One hormone medicine on its own. In feminizing care, estrogen without a separate anti-androgen, which works only if testosterone is actually suppressed.
P
Peak and Trough
The highest and lowest levels between doses. Why the timing of a blood test matters as much as the number, and why some people feel the swing.
Prolactin
A pituitary hormone that estrogen and cyproterone can raise. Usually a small, harmless rise; checked in case it keeps climbing.
S
SHBG
A blood protein that binds sex hormones. It decides how much of your total level is actually free to act, and oral estrogen and testosterone push it in opposite directions.
Spironolactone
The usual US anti-androgen. Cheap and mild; causes frequent urination and light-headedness, and needs potassium checks.
T
Testosterone Undecanoate
A long-acting testosterone injection given every few months. Common outside the US; steadier levels and fewer jabs, but slower to adjust.
Transdermal
Through the skin: patches, gels and sprays. Lower clot risk than oral estrogen and steady levels; gel can transfer to other people.
W
WPATH
The international professional body behind the Standards of Care, the guidelines most clinics and insurers point to. Guidelines, not law.
Not sure where to begin?
The Start Here guide covers what hormones change, how people get a prescription, what the blood tests are for and what it costs.
start here →