Muscle Protein Synthesis

Androgen Receptor

The receptor every anabolic-androgenic steroid is designed to hit. Binding moves it into the nucleus where it switches on genes for muscle protein synthesis, and in other tissues for hair loss, prostate growth and oil production.

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.

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.

Lean Mass

Muscle actually gained. The reason any of this is being taken.

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.

Skeletal Muscle

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

Strength

Force produced. Rises faster than tendon and ligament can adapt, which is the risk built into the benefit.

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.