Immune FormulaMagnesium Helps D3 Work BetterPotent Combination in 1 Tablet Per DayVitamin D3 157.5 mcg (6,300 IU)Magnesium 100 mg as Magnesium CitrateDietary SupplementSuperior Absorption of Both Vitamin D3 & Magnesium Citrate†2 Essential Nutrients in One Tablet - Each in Their Optimal FormGuaranteed QualityLaboratory TestedSupports Immune Health 5 Years of Trusted Quality At Nature's Bounty, we are committed to your health. For 50 years we have been making trusted products, backed by science, and made with only the purest ingredients ... guaranteed. So you can get the most out of life every day. Vitamin D is involved in all 3 layers of immune support: Role in skin and barrier functionFunction & movement of immune cellsNormal functioning of T-Cells & B-Cells Magnesium is needed for conversion of Vitamin D to its "active" form. Magnesium helps Vitamin D3 work better for Immune Support^ ^Getting enough Magnesium daily assists in converting Vitamin D to its active form, which supports immune health. Magnesium helps Activate Vitamin D3 for: Helping in the maintenance of the Immune SystemSupporting muscle and bone health Nearly 80% of Americans aren't getting enough Magnesium daily.♢ More than 90% of Americans don't get enough Vitamin D daily.♢ †Vitamin D3 is a more bioavailable form compared to D2. Magnesium Citrate is a more bioavailable form compared to other forms including Magnesium Oxide. ♢NHANES, 2001-2006