Androgen

An androgen is any hormone that drives the changes of a testosterone-led puberty: a deeper voice, facial and body hair, more muscle, and oilier skin. Testosterone is the main one, and dihydrotestosterone (DHT), which the body makes from it, is the most potent.

Where you'll meet it

In the names of the medicines that block them (anti-androgens), on blood results, and in almost every conversation about feminizing hormones, where lowering androgens is half the job. On masculinizing hormones the word turns up less, but it is the whole point: testosterone is an androgen, and the changes you are after are androgen effects.

Everyone has them

Androgens are not a male-only hormone. Every body makes some, from the testes, the ovaries and the adrenal glands, and the difference between people is mostly in how much. That is why a lab sheet has reference ranges for both sexes, and why neither range fits a trans person on hormones very well.

The adrenal glands keep making a small amount of weaker androgens (DHEA is the one you may see named) whatever else is going on. They are not enough to masculinize someone, and they are why testosterone on a blood test rarely reads as zero, even after an orchiectomy.

How androgens work

An androgen acts by fitting into a receptor on a cell, the androgen receptor, a bit like a key in a lock. Skin, hair follicles, the voice box, muscle and genital tissue are all full of them. There are two broad ways to cut an androgen's effect: make less of it (spironolactone partly, cyproterone, a GnRH agonist, estrogen itself), or block the lock so the key cannot turn (bicalutamide, and spironolactone partly). That difference is why testosterone on a blood test means different things depending on which medicine you take.

Why DHT gets its own mention

Much of what people dislike about androgens, scalp hair loss and body hair especially, is driven by DHT rather than testosterone itself. An enzyme called 5-alpha reductase makes the conversion, and some hair-loss medicines work by blocking it. Some feminizing prescribers add one for scalp hair; it is not a standard part of most regimens.

On masculinizing hormones, DHT is also why someone on testosterone may start losing hair from the crown or temples, if it runs in the family. Blocking DHT can slow that, but it can also slow the growth of facial and body hair and some genital growth, which is the trade-off the masculinizing risks page mentions.

How it's measured

Most monitoring measures total testosterone, as the stand-in for androgens as a whole. On feminizing hormones, guidelines commonly cite a target under about 50 ng/dL (under about 1.7 nmol/L). On masculinizing hormones, the aim is roughly the typical adult male range, often given as around 400 to 700 ng/dL (about 14 to 24 nmol/L). Your prescriber sets your actual target. DHT is rarely tested routinely. SHBG, a protein that carries testosterone in the blood, is sometimes checked when the total figure and how you feel do not match. How to read your hormone blood results explains the units.

Common questions

More is faster. On testosterone, pushing the level above the target range does not bring changes faster in any reliable way. It mostly raises hematocrit and side effects.

Androgens are the enemy on feminizing HRT. Lowering them is the aim, but the remaining trace matters less than people fear, and a very low figure is not a sign you are doing better than someone at the top of the target range.

What to ask

Ask which of your medicines lowers androgens and which blocks them, and what your testosterone result is expected to look like as a result. If scalp hair loss worries you, on either plan, ask what options your prescriber is willing to discuss and what each one costs you in other changes.

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