Sobetirome (GC-1)
Sobetirome (GC-1) is a synthetic thyroid hormone receptor beta-selective agonist investigated for dyslipidaemia and, later, demyelinating disease. It lowers cholesterol and raises metabolic rate in animals with reduced cardiac effect, and circulates in the fat-loss grey market.
01 Overview
Sobetirome was one of the first designed TR-beta-selective thyromimetics, showing potent lipid-lowering and metabolic effects in rodents and early human work with minimal tachycardia. Interest later shifted to central nervous system applications after a brain-penetrant prodrug (sobetirame/sobetirome ester) showed remyelinating potential.
02 Mechanism
Selective thyroid hormone receptor beta agonist that activates hepatic and metabolic gene programmes (lipid oxidation, LDL clearance, thermogenesis) while largely sparing cardiac TR-alpha.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Grey-market (unvalidated) | 50–100 mcg/day | Oral | No established human protocol; extrapolated only |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Cholesterol loweringPotent lipid lowering demonstrated in rodents and primates. | Large LDL reduction in animals | Preclinical | |
| Increased metabolic rateRaises energy expenditure and fat oxidation in animal models. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Thyroid axis suppressionCentral TSH suppression expected from thyromimetic action. | Moderate | Expected | Preclinical | |
| Unknown human safetyLong-term human safety, including cartilage/liver effects seen in the class, is undefined. | Moderate | Uncharacterised | Unconfirmed |