THRB
THRB thyroid hormone receptor beta — the molecular target that 1 compounds in the wiki act on.
In one line: The thyroid-hormone receptor — your body's metabolic thermostat.
THRB is a receptor for thyroid hormone, which sets your whole-body metabolic rate — how fast you burn energy. Too little and everything slows (fatigue, weight gain, cold); the right amount keeps metabolism humming.
Thyroid medication works here to treat an underactive thyroid. Some physique competitors misuse it to burn faster, but that also burns muscle and suppresses your own thyroid — so it's a legitimate medicine and a risky shortcut, depending on how it's used.