USANA's Booster C 600 product is designed to provide seasonal immune system support. It contains zinc, echinacea extract (Echinacea purpurea), black elderberry extract, and vitamin C, including USANA's proprietary Poly C® blend. Additionally, this product is provided as a lemon-berry flavored powder that can be taken directly or mixed with water, juice, or other beverages.

Most research on echinacea extract has looked at short-term use beginning at the onset of cold or flu symptoms. Research on efficacy and safety during long-term use is less established. Because of the potential for unwanted side-effects from overstimulation of the immune system, USANA's Booster C 600 product should not be used continuously for more than two weeks at a time.