From the Manufacturer:
Carotenoids are often called pro-vitamin A, since the body can convert some carotenoids to vitamin A. The carotenoids that can be converted to vitamin A are alpha, beta and gamma carotenes and beta cryptoxanthin. The body uses vitamin A to maintain healthy vision, skin and nails, a strong immune system, and for reproduction and growth. The carotenoids without pro-vitamin A activity continue to be studied, but a few are so newly discovered that little is known about them.