According to Dr. Anthony Fauci, most "so-called immune boosting supplements" actually do "nothing." However, there are two vitamins Fauci does recommend to help keep your immune system healthy.

"If you are deficient in vitamin D, that does have an impact on your susceptibility to infection. So I would not mind recommending, and I do it myself taking vitamin D supplements," Fauci, 79, said during an Instagram Live on Thursday, when actress Jennifer Garner asked Fauci about immune-boosting supplements.