Because optimal immune function is an important part of long-term wellness, it is essential to provide immune function support during times of high stress, seasonal changes, and when you aren’t feeling your best. Thorne’s Immune Support Stack includes the following three products Zinc Picolinate 30 mg is a highly absorbable form of zinc, which is well known for supporting immune function. Clinical studies demonstrate zinc supplementation can increase general wellness, in addition to having a beneficial impact on connective tissue.* Vitamin D3 supports immune function, healthy bones and muscles, and cardiovascular health.* Vitamin C with Flavonoids promotes optimal immune function and is important for collagen production.*