DOSEGUY

GC-1

guinea pig

Also seen as: Sobetirome

The Dose Guy’s verdict
Sep 1, 2026
4 sources

GC-1 is a clever idea with no human evidence behind it. A thyroid-receptor agonist built to hit the liver and spare the heart, which would solve the biggest problem with running thyroid hormones for a cut. But that promise lives entirely in animal studies and one primate. Until someone puts it in a person for fat loss, it stays on my watch list, not in a protocol.

Would I take it?No, still a lab compound.

What it is

GC-1 is a synthetic thyromimetic, a molecule shaped to activate thyroid hormone receptors without being thyroid hormone. The pitch is selectivity: it prefers the beta receptor, which drives liver metabolism, cholesterol clearance, and fat oxidation, over the alpha receptor, the one that speeds your heart, wastes your muscle, and thins your bones. That split is why liothyronine works but costs you, and why a compound that could deliver the metabolic burn without the systemic ride would matter.

The receptor preference predicts that GC-1’s effects concentrate in the liver and spare the heart and skeleton. The metabolic numbers in mice and one monkey are real, but nobody has tested whether that selectivity holds in a person running it for body composition.

What the research shows

No human trials. Zero. Everything below is animal or in-vitro work. Read it as “interesting,” not “evidence it works in you.”

Zero human trials for obesity or weight loss. The entire case rests on rodents and one monkey:

In diet-induced obese mice, sustained GC-1 delivery significantly reduced body weight and fat mass within 10 days and reduced serum cholesterol and glucose within 7 days.Sci Rep 2016 · mouse
In one obese prediabetic rhesus macaque, four months of sustained low-dose GC-1 delivery reduced abdominal white adipose tissue from 36% to 18% by MRI.2018 · case study · n=1 · 4 months
In high-fat-fed male rats, GC-1 caused fasting hyperglycemia and hyperinsulinemia through increased endogenous glucose production and reduced hepatic insulin sensitivity.Diabetes 2013 · rat
In a cholestasis mouse model, dietary GC-1 for two to four weeks raised serum transaminases and retained bile acids in hepatocytes.Am J Pathol 2020 · mouse
No randomized human efficacy trial of GC-1 for obesity or weight loss exists.as of Aug 2026

Realistic protocols

There’s no defensible human protocol for GC-1. Nobody has measured a dose, a timeline, or a side-effect profile in a person for this purpose. The vendor world sells it as a research chemical at oral doses loosely extrapolated from animal work, but that math is a guess, not a protocol. If you run it anyway, start at the lowest dose you can source, keep the run short, and get a thyroid panel, liver enzymes, fasting glucose, and lipids before and after. You’re the experiment, and a thyromimetic that raised liver enzymes in mice deserves more monitoring, not less. For an actual thyroid-driven cut with human data behind it, liothyronine exists, warts and all.

Side effects

No human safety data exists, so everything here is extrapolated from animals:

monitorFasting blood sugar may rise. The rat data showed hyperglycemia and insulin resistance at the liver, the opposite of what you want on a cut.
monitorGC-1 raised liver transaminases and retained bile acids in hepatocytes in mice. For a compound whose entire pitch is targeting the liver, a liver-injury signal deserves respect. Check liver enzymes.
unknownThe whole point of GC-1 is sparing the heart and bone. Whether it actually does that in a human at the doses vendors sell is untested. If it doesn’t, you’re running unmonitored thyroid hormone.
unknownLong-term effects on the thyroid axis are unknown. Whether GC-1 suppresses endogenous thyroid production the way liothyronine does hasn’t been measured in a person.

Where to buy

All American Aminos–
$50 / unit
✓ verified Sep 12
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