ATX-304: The Easy Guide for 2026

AMPK (AMP-activated protein kinase) is your body’s energy sensor. It switches on when energy runs low, such as during:

• Exercise
• Fasting
• Calorie restriction

When AMPK turns on, cells burn more fuel and take in more glucose. That’s why ATX-304 is often compared to exercise.

Scientists have tried to target AMPK for years, but no direct AMPK activator has been approved yet.

ATX-304 keeps AMPK switched on longer. It does this by slowing the removal of the “on” signal (a phosphate group) from AMPK.

In research, this led to:

• More glucose uptake in muscle
• More fat burning
• Less fat production in the liver
• Higher energy use by cells

Phase 1b Trial (2026)

In June 2026, Cambrian Bio presented results from an 8-week, double-blind, placebo-controlled trial in prediabetic adults with overweight or obesity.

The company reported statistically significant improvements in:

These results were presented at the American Diabetes Association’s 2026 meeting.

Phase 2a Trial in Type 2 Diabetes

An earlier 28-day trial tested O304 in people with type 2 diabetes who were also taking metformin. Results showed:

• Lower fasting blood sugar
• Better insulin sensitivity (HOMA-IR)
• Improved blood flow in small blood vessels
• Lower blood pressure

No safety signals were observed, and the compound was well tolerated.

Animal Studies

• Fatty liver: In mice with progressive fatty liver disease, ATX-304 reduced body fat, lowered cholesterol, and reduced liver fat and scarring.
• Exercise-like effects: In mice, O304 activated AMPK in the heart, increased glucose uptake, and improved heart pumping, similar to exercise.

Early trials have reported it as well tolerated, with no safety signals in the Phase 2a study. But the trials were short and small, so long-term safety is still unknown.

No. ATX-304 is an investigational compound still in clinical development.

Based on the Phase 1b results, Cambrian Bio plans to move ATX-304 into Phase 2 studies at higher doses to test its effects on body weight, fat loss, and energy use.

• What is ATX-304? An investigational oral AMPK activator being studied for obesity, diabetes, and fatty liver disease.
• Is ATX-304 a peptide? No. It’s a small molecule taken by mouth.
• Why is ATX-304 called an exercise pill? It activates AMPK, the same energy sensor that turns on during exercise.
• Does ATX-304 cause weight loss? The Phase 1b trial showed less liver and belly fat and higher resting metabolism. Phase 2 trials will test weight loss directly.
• Is ATX-304 FDA-approved? No. It’s still in clinical trials.

• ATX-304 (O304) is an oral AMPK activator, not a peptide.
• It works by boosting how cells use energy, unlike appetite-suppressing GLP-1s.
• 2026 Phase 1b results showed less liver and belly fat and higher resting metabolism.
• Early trials found it well tolerated, but long-term safety is unknown.
• It’s not FDA-approved and is heading into Phase 2.

• JCI Insight (PMC) – PAN-AMPK Activator O304 Improves Glucose Homeostasis and Microvascular Perfusion in Mice and Type 2 Diabetes Patients (2018)
• JCI Insight – AMPK Activator ATX-304 Reduces Oxidative Stress and Improves MASLD via Metabolic Switching
• Business Wire via Times Argus – Cambrian Bio Presents Positive Human Data for ATX-304 (June 2026)
• Cambrian Bio – Amplifier Therapeutics Doses First Patients in Phase 1B Trial (2023)
• Betagenon – Phase IIa Results of O304 in Type 2 Diabetes (2017)
• CORDIS (European Commission) – AMPK-DIAB Project: O304 for Type 2 Diabetes