In terms of how, exactly, the vitamin affects skin health, we know that vitamin D has anti-inflammatory and antioxidant properties that help protect skin cells.* Plus, vitamin D plays a crucial role in thyroid health as it helps regulate the production of thyroid hormones3.* These thyroid hormones play a key role in keeping your hair, skin, and nails youthful and strong (in addition to influencing metabolism, mood, sleep, etc.).ย