5 Reasons You Get a Metallic Taste in Your Mouth (And How to Avoid It) 9 Mouth and Lip Changes That Can Signal Vitamin B12 Deficiency AOL Vitamin B12 deficiency symptoms: Metallic taste in your mouth can mean you're lacking B12 Express.co.uk A metallic taste or constant dry mouth are symptoms you should never ignore. These issues can often signal underlying medical or oral health concerns. Low saliva allows bacteria to grow which