Our D-3 ActivMelt® Instant Dissolve Tablets 1000 IU (25 mcg) are formulated for simple yet efficient support. Vitamin D plays an essential role in how your body absorbs calcium and phosphorus, and though your skin can get it from the sun, prolonged time spent indoors makes it harder to get it naturally. It also helps support your immune system - and when you feel healthy, you feel good! Our ActivMelt® technology allows for quick and easy digestion, melting quickly on your tongue without the need for water.