Nov 30, 2025 · Most adults need at least 15 micrograms (mcg)—or 600 international units ( IU)—of vitamin D daily to maintain healthy levels. 1 The amount recommended for children and older adults …

Aug 2, 2022 · More specifically, you need vitamin D so your body can use calcium and phosphorus to build bones and support healthy tissues. With chronic and/or severe vitamin D deficiency, a decline …

May 21, 2025 · Serum 25-hydroxyvitamin D — Vitamin D sufficiency is estimated by measuring 25-hydroxyvitamin D (25 [OH]D or calcidiol) concentrations. The optimal serum 25 (OH)D concentration …

Apr 25, 2025 · Learn about normal vitamin D levels by age. This article also looks at sources of vitamin D, symptoms of vitamin D toxicity, and more.

Mar 21, 2025 · Taking a vitamin D supplement or a multivitamin with vitamin D may help improve bone health. The recommended daily amount of vitamin D is 400 international units (IU) for children up to …

Nov 27, 2025 · Vitamin D is a fat-soluble nutrient that functions as both a vitamin and a prohormone, playing a fundamental role in the body’s systems. It is necessary for the absorption of calcium and …

Aug 15, 2025 · Vitamin D deficiency is one of the most common nutrient gaps worldwide. Even if your levels are “normal,” they may not be optimal for long-term health. This guide explains how to interpret …

Vitamin D levels of 30 to 100 ng/mL are considered optimal. Vitamin D levels between 20 and 29 ng/mL are considered suboptimal. Vitamin D insufficiency may lead to elevated parathyroid hormone (PTH) …

Nov 1, 2024 · In the general population, adults ages 19 and older don't require routine testing of vitamin D levels. However, they should follow the U.S. National Academy of Medicine's Recommended …

Feb 17, 2025 · Normal vitamin D levels typically fall between 30-100 ng/mL. Anything below 30 ng/mL indicates deficiency, while levels above 100 ng/mL could signal excessive amounts in the body. Too …