The Weird Reason Your Lip Tastes Like Metal

You're brushing your teeth in the morning. You're not sure if you've accidentally done anything to your gums until you rinse out the toothpaste and gargle some water to wash out your mouth. Suddenly, there's a metallic taste on your lips. Or maybe the memory is from your childhood: You were playing outside, and you cut your finger on a sharp edge and instinctively put your bleeding thumb in your mouth to suck on it and supposedly stop the bleeding. Again, you taste metal. 

It's safe to say that the reason for the weird taste is your own blood. Perhaps you saw the TikTok video of what it means if your mouth tastes like blood after working out. While there are several serious reasons for this, there is also the possibility that you accidentally bit down on your lip while moving about. But why exactly does blood taste like metal? 

Mostly, this has to do with what's in your blood, per ASH US. Blood contains red blood cells, white blood cells, platelets, plasma, and organic and inorganic substances like iron, glucose, enzymes, lipids, hormones, and amino acids. What gives blood its metallic taste is iron, or more specifically, how the said iron interacts with your taste buds. Your saliva contains metal-binding proteins called chelators. When these proteins come into contact with the iron ions in your blood, your brain registers the taste of metal on your lips.

The iron in your blood has a very specific and important role, according to the University of California San Francisco Health. Quite a concentration of your body's iron content is found in the protein called hemoglobin that's present in your red blood cells. Hemoglobin is responsible for transporting oxygen from your lungs to the tissues. The iron ions binding to the oxygen in your blood are an important part of this exchange, per ASH US. The iron found in hemoglobin is also what gives blood its characteristic red hue. This happens when the iron content comes into contact with oxygen. 

Now that you know the main reason why your mouth tastes like metal when there's blood in it, it might be worth looking into other potential explanations. There are instances when a metallic taste in your mouth may indicate a more serious predicament, and not all of them have to do with the presence of actual blood.

Gum diseases like gingivitis or periodontitis, sinus infections, food allergies, pregnancy-induced hormone changes, nerve damage due to dementia, and chronic kidney disease (CKD) can all lead to a metallic taste in your mouth, according to Insider. 

You may have also heard of people going through chemotherapy and tasting metal on their lips. "While the intention of the therapy is to target cancer cells, they can sometimes damage healthy oral cells and lead to a metallic taste," shared Dr. Natasha Bhuyan, National Medical Director at One Medical, with Insider. Certain medications and supplements can also leave your mouth tasting of metal. "Medications that may have a bloody-taste side effect include antibiotics, antidepressants, and blood pressure and diabetes medications. Multivitamins, especially those with heavy metals or iron may cause a blood-taste side effect," explained practicing pediatrician Dr. Lisa Lewis (via Health). 

It is important to know the difference between a metallic taste due to toothbrush-induced gum bleeding and other, more serious health conditions. In the event that you suspect that it's the latter, make an appointment with your healthcare provider.