What is Lumen?

Content last verified May 4, 2026 · by the AI Tools Set Research Team

Lumen is a handheld device and app that measures your metabolism from your breath and uses AI to give daily personalized nutrition and workout guidance based on whether you are burning fat or carbs. It helps optimize metabolic flexibility.

Health-focused users use it to understand and improve their metabolism, receiving tailored meal and activity recommendations each day.

Key Features of Lumen

Metabolic measurement: Breath-based fat vs carb reading.
Daily AI guidance: Personalized nutrition targets.
Workout suggestions: Activity based on metabolism.
Progress tracking: Metabolic flexibility over time.

Use Cases for Lumen

Measure metabolism
Optimize nutrition
Improve metabolic flexibility
Guide daily eating
Track health

Pros & Cons

Pros

✓

Unique metabolic data

✓

Daily personalization

✓

Actionable guidance

✓

Holistic

Cons

✗

Requires a device

✗

Subscription plus hardware

Pricing

Device

$249 one-time

✓Lumen device

✓App access

✓Onboarding