Androgen Receptor

Nitrogen Retention

Whether the body is holding more protein than it loses. A practical readout of net anabolism rather than a mechanism in its own right.

Prostate-Specific Antigen

Tracks prostate activity and size. Useful mostly as a trend in men over forty rather than a single reading.

Adipose Tissue

Stores fat and houses most of the body's aromatase, so more fat mass means more conversion of androgen to estrogen.

Amygdala

The threat detector. Dense in androgen receptors, and the structure most implicated in the anger, vigilance and fear side of what these compounds do. Splitting it out of the limbic system matters because threat processing and reward processing sit in the same blob otherwise, and compounds pull them in opposite directions.

Bone Marrow

Where red cells are built. Androgens push it harder, which is why they were once a treatment for anaemia and why haematocrit climbs on cycle.

Heart Muscle

Carries androgen receptors like skeletal muscle does, and thickens under the same signal. Unlike a bicep, a thicker left ventricle fills less well.

Kidney

Controls sodium and water balance and produces erythropoietin, so it sits behind both the bloat and the rising red cell count.

Limbic System

The emotional core of the brain, and androgen-receptor rich. This is where mood, threat response and aggression are set, and where steroid mental effects are thought to land.

Prostate

Growth here is driven mainly by DHT rather than testosterone, which is why compounds that resist 5-alpha-reductase are gentler on it.

Scalp Hair Follicle

In a genetically susceptible scalp, DHT binding shrinks the follicle a little with each cycle. The predisposition is inherited; the androgen sets the pace.

Sebaceous Gland

Oil glands in the skin. Androgen signalling raises output, and heavier oil plus keratin plugging is how steroid acne starts.

Skeletal Muscle

The intended target. Dense in androgen receptors, and the tissue where the whole risk trade is being made.

Tendon and Ligament

Connective tissue adapts far slower than muscle. A strength jump that outpaces it is the setup for a tear.

Testis

Makes testosterone and sperm, and needs LH and FSH from the pituitary to do either. Cut that signal and it shrinks and goes quiet.

Acne

Oil production plus blocked follicles, worst on back and shoulders. Tracks androgenic strength more than dose.

Male Pattern Hair Loss

Permanent thinning at the crown and hairline in those genetically predisposed. Androgens accelerate a process that was already going to happen, and the loss does not come back.

Prostate Enlargement

A larger prostate with weaker urine flow and night waking. Driven by DHT more than by testosterone itself.

Virilization

Male traits appearing in a female user: deeper voice, facial and body hair, clitoral growth. Voice change and clitoral growth are usually permanent, which makes this the one side effect that cannot be managed after the fact.

Androgen Receptor Density

How many androgen receptors a tissue actually has. It is not fixed: training raises it, and sustained high-dose exposure lowers it in some tissues, which is part of why results flatten and doses creep upward.

Collagen Synthesis

Building the protein that tendon, ligament, joint surface and skin are made of. It moves slower than muscle does, and not every androgen supports it equally.

Gene Transcription

Genes being read into protein. The androgen receptor is a transcription factor, so this is the actual first step after binding: everything else downstream is a consequence of which genes get switched on and in which tissue.

Muscle Protein Synthesis

The rate at which muscle is built. Androgen receptor activation raises it and holds it raised, which is the entire point of the exercise.

Myonuclei

The nuclei inside a muscle fibre, each running a patch of it. Androgens add them, and animal work shows the added ones persist for a long time after the drug is gone. This is the cell-level reason a past cycle is never entirely undone.

Red Blood Cell Production

Red cell manufacture, driven by erythropoietin from the kidney. Androgens raise both the signal and the marrow's response to it.

Satellite Cells

Dormant stem cells beside each muscle fibre. Androgens push them to divide and fuse into the fibre, which is where new myonuclei come from.

Androgen Receptor Density

How many androgen receptors a tissue actually has. It is not fixed: training raises it, and sustained high-dose exposure lowers it in some tissues, which is part of why results flatten and doses creep upward.

Myostatin Signalling

The body's own brake on muscle growth. Lowering it removes a ceiling rather than adding a push, which is a different kind of effect from raising protein synthesis.

Protein Breakdown

Muscle being taken apart, driven largely by cortisol at the glucocorticoid receptor. Blocking it is the anti-catabolic half of how steroids work.