Vitamin deficiencies that can cause dry skin include vitamins D and A. Deficiencies in niacin, iron, or zinc can also cause dry skin. Learn More: Best At-Home Micronutrient Testing 11 Sources 8 Best Vitamins and Supplements for Dry Skin. 1. Vitamin D. Vitamin D is a fat-soluble vitamin that’s critical for many aspects of health, including the health of your skin. Keratinocytes are skin 2. Collagen. Collagen is the most abundant protein in your body and accounts for 75% of your skin’s uassONN.

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