Immune System Support Glutamine is the main fuel source for your body’s lymphocytes, white blood cells that fight infection and disease. But your blood’s glutamine levels decline when we’re sick or injured, reducing these immune cells’ ability to defend your body. While there’s conflicting evidence on whether it boosts immunity in healthy people, studies show it can improve recovery times and reduce complications when you’re sick. Many clinical studies show that glutamine helps ease the effects of cancer treatments, like muscle wasting, oral inflammation, nausea, vomiting, and diarrhea. Supplementation is also linked with shorter hospital stays and lower mortality rates for sick patients.