Yam-A is sourced from yam varietals, containing carotenes, and from salmon, containing retinol, plus balckberry leaves containing beta carotene and vitamin D. A is main the vitamin that supports pineal function, keeps sinuses, lungs, and eyes moist, maintains cell wall strength, and helps convert proteins into tissue. Vitamin A maintains the health of the thymus gland, assists integration of magnesium into bones, supports light and dark seeing, aids stomach and colon to secrete protective mucous, and is a super anti-oxidant. Each drop provides approximately 1,100 I.U. vitamin A, plus 25 I.U. vitamin D, the synergistic ratio of A to D necessary for absorption, which regulates the metabolism of calcium and phosphorus.