Emergen-C is one of the most recognizable vitamin C supplements in the world. Each box comes with 30 individual packets, and each packet contains 1,000 mg of vitamin C.

Airborne and Emergen-C are designed to boost your immune system. Both supplements contain high levels of vitamin C, but Airborne also has riboflavin (vitamin B2), zinc, and herbs.

Pfizer Inc on Monday said it had acquired privately held Alacer Corp, the largest U.S. maker of vitamin C products, bolstering Pfizer's array of vitamin brands and its consumer healthcare business.