Peptide Library/Fat Loss & Metabolic/GC-1

GC-1

InvestigationalModerate Research

Also known as: Sobetirome · Thyroid Receptor Beta Agonist

A selective thyroid hormone receptor beta agonist that enhances metabolic rate and fat oxidation without the cardiac side effects of traditional thyroid hormones.

Overview

GC-1 (Sobetirome) is a selective thyroid hormone receptor beta (TRbeta) agonist that provides the metabolic benefits of thyroid hormone — increased metabolic rate, enhanced fat oxidation, and improved lipid profiles — without the cardiac side effects mediated by thyroid receptor alpha (TRalpha). Traditional thyroid hormones (T3/T4) activate both receptor subtypes, with TRalpha mediating cardiac effects (tachycardia, arrhythmia risk) and TRbeta mediating metabolic effects (cholesterol reduction, fat oxidation, energy expenditure). GC-1 selectively activates TRbeta, providing a cleaner metabolic enhancement profile. In clinical studies, it has demonstrated significant reductions in LDL cholesterol and triglycerides while increasing metabolic rate.

It is also being studied for its potential in treating X-linked adrenoleukodystrophy (X-ALD) and non-alcoholic fatty liver disease.

Mechanism of Action

Selectively binds and activates thyroid hormone receptor beta (TRbeta) with ~10x selectivity over TRalpha. TRbeta activation in the liver increases LDL receptor expression (lowering cholesterol), enhances fatty acid oxidation, and increases energy expenditure. In the brain, TRbeta activation may promote remyelination.

Key Benefits

Increased metabolic rate

Enhanced fat oxidation

Significant cholesterol reduction

No cardiac side effects (TRbeta selective)

Potential liver fat reduction

May support brain health and myelination

Potential Side Effects

Potential thyroid axis suppression with extended use

Mild GI discomfort

Headache (uncommon)

Monitor thyroid function

Common Stacks

This peptide is commonly combined with the following compounds for synergistic effects:

AICARCardarine (GW-501516)L-Carnitine5-Amino-1MQ

Known Interactions

The following interactions have been documented for GC-1. Always consult a healthcare professional before combining compounds.

Contraindicated (1)

Thyroid (T3/T4)Contraindicated

GC-1 is a thyroid receptor beta agonist. Combining with exogenous thyroid hormone risks thyrotoxicosis — excessive thyroid signaling affecting heart, bones, and metabolism.

View all compound interactions

Scientific References

GC-1, a Thyroid Hormone Receptor Beta-Selective Agonist, Reduces Cholesterol in Humans

Ladenson PW, Kristensen JD, Ridgway EC, et al.

Journal of Clinical Endocrinology & Metabolism (2010)

Sobetirome: A Case History of Bench-to-Clinic Drug Discovery and Development

Scanlan TS

Heart Failure Reviews (2010)

Quick Reference

Typical Dose

100mcg-500mcg

Frequency

1x daily AM

Route

Oral or injectable

Half-Life

~8-12 hours

Cycle Length

4-16 weeks; 5 on 2 off or daily, followed by 4-6 weeks recovery

FDA Status

Investigational — Phase 1 clinical trials completed. Being developed for X-ALD. Not yet FDA approved.

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This information is for educational purposes only. Consult a qualified healthcare professional before using any peptide. Dosing information reflects commonly reported protocols and may not be appropriate for everyone.

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