For most healthy adults ages 19 to 70, the recommended daily amount of vitamin D is 600 IU, or 15 mcg. Adults over age 70 generally need 800 IU, or 20 mcg, per day. These amounts include vitamin D obtained from food, fortified products, and supplements.
Taking more vitamin D3 is not automatically better. Current guidance does not recommend routinely taking higher doses simply to prevent conditions such as cancer or cardiovascular disease in otherwise healthy adults under age 75. Vitamin D3 tends to raise and maintain vitamin D levels more effectively than vitamin D2.
Higher doses may be appropriate in certain situations, including documented vitamin D deficiency, osteoporosis, malabsorption, pregnancy, or other specific health conditions. In these cases, the appropriate dose can vary significantly, so the standard daily recommendation should not be treated as a treatment dose. Learn more about vitamin D3 and its health benefits.
It is also important to count vitamin D from all supplements, including multivitamins and calcium products. Avoid taking very high or intermittent megadoses without medical guidance. If you have a known deficiency, kidney disease, kidney stones, or another condition that affects vitamin D levels, speak with your doctor before choosing a dose.