Your ALT Blood Test Is Low: That Might Say More About Your Muscles Than Your Liver
Most people only hear about ALT (alanine aminotransferase) when it's elevated, a signal that something may be stressing the liver. But a growing body of research points in the opposite direction: unusually low ALT levels, especially in older or chronically ill adults, can be a quiet marker of frailty, muscle loss, and higher long-term mortality risk. It's not the kind of thing most doctors flag on a routine blood panel, yet multiple large cohorts consistently tie it to worse outcomes. ALT is an enzyme found mostly in your liver, but also in your muscles. When levels drop below a certain floor, it may reflect that there's simply less metabolically active tissue producing it. That shift matters more than most people realize.