Last updated: May 8, 2026

Onyx is a fitness and recovery tracking app. It is not a medical device. It is not a diagnostic tool. It is not a substitute for advice from a licensed healthcare provider.

What Onyx does

Onyx reads metrics from Apple Health (heart rate variability, resting heart rate, sleep, body temperature, etc.) and uses them to:

• Compute a daily recovery score
• Surface illness early-warning patterns when several signals shift away from your baseline at once
• Recommend training intensity and nutrition in light of your current state
• Power Coach, an AI assistant that reasons against your data

These are signals. Useful ones. But signals can be wrong, especially during the first weeks of use while your baselines stabilize.

What Onyx is not

Onyx is not:

• A diagnosis
• A prescription
• A replacement for a doctor, nurse, dietitian, physical therapist, or any other healthcare professional
• A substitute for emergency medical care

When to see a clinician

See a healthcare professional if you experience any of the following, regardless of what Onyx says:

• Persistent or severe symptoms (chest pain, shortness of breath, fever, dizziness, etc.)
• New or worsening pain during exercise
• Symptoms that don't improve with rest