Before you start
Sit comfortably and allow yourself a quiet rest first. Avoid starting immediately after rushing, climbing stairs or exercising if you want a resting check-in. Follow any product-specific instructions about eating, caffeine, smoking or timing. Use the same general time and routine when trying to understand a trend.
Set up the camera
Use steady, even light on your face. Avoid a bright window behind you, rapidly changing light and strong shadows. Place the device on a stable surface, clean the lens and frame your uncovered face inside the guide. Remove anything that blocks a large area of skin if it is safe and comfortable to do so.
During and after the scan
Keep still, look toward the camera and breathe normally. Do not talk unless asked. If the app reports poor quality, adjust conditions and try again rather than relying on the number.
A result that differs from your normal pattern is a reason to repeat carefully, not an automatic conclusion. Record context such as illness, stress, poor sleep or recent activity if the product allows it.