Hemoglobin gives blood its red color, which shows through your skin as a healthy complexion. When iron is low, hemoglobin drops, and you become noticeably pale. Check your inner lower eyelids — pull them down gently and look in a mirror. They should be vibrant red. If they're pale pink or white, you may be significantly iron deficient. Your gums, nail beds, and lips may also appear paler than usual.