Vitamin C is important to take at the onset of an illness because it helps to boost the immune system to fight off the sickness. Vitamin C has been shown to reduce the severity and length of the common cold. 

How Vitamin C Works:

1) Vitamin C enters white blood cells and helps them function as they should. White blood cells are the primary defense against sickness in the body. 

2) Vitamin C protects white blood cells from being damaged through oxidative stress, allowing white blood cells to function better.

3) Vitamin C helps recycle the cells that cause illness, so they don’t cause further inflammation and issues in the body.