Vitamin D3 can help sustain adequate Vitamin D levels throughout the year, which can be difficult for the body to produce - especially during the winter. A supplement of Vitamin D3 can support healthy bone density and promote healthy cell differentiation and immune function for better health. Why it Works: Vitamin D3 can be synthesized by humans in the skin upon exposure to ultraviolet-B (UVB) radiation from sunlight. Because of weather conditions during the winter season and sunblock, the body’s ability to produce vitamin D levels within the normal range may be inhibited. A supplement of Vitamin D can support healthy bone density and promote healthy cell differentiation and immune function for better health. These factors indicate the value of taking a daily vitamin D supplement. Vitamin D provides significant support for healthy bone density [1-7]. Furthermore, scientists have validated the critical role that vitamin D plays in regulating healthy cell division and differentiation, as well as its profound effects on human immunity [8-14]. These findings link a deficiency of vitamin D to a wide variety of common age-related problems. The Science Behind the Product: Even if we are able to make some amount of vitamin D in our bodies, we often still need extra amounts of vitamin D to maintain adequate levels This additional amount of vitamin D can come from our diet, sun or supplements LifeExtension recommends that healthy adults supplement 5,000 IU – 8,000 IU vitamin D3 on a daily basis. It is also recommended to take a 25-hydroxy vitamin D blood test, 3 months after one has started taking daily vitamin D3 supplementation of the dose described above. Finally, LifeExtension advice that one adjusts the daily vitamin D3 dosage, so that one’s optimal blood levels will be between 50-80ng/mL on a year-round basis. When vitamin D is ingested in the diet or produced in the skin, the liver and kidneys convert vitamin D to its active form known as 1,25-dihydroxyvitamin D, or vitamin D3. Virtually every tissue type in your body has receptors for vitamin D, meaning that they all require vitamin D for adequate functioning. Besides its role in bone health, vitamin D is responsible for regulation of genes that control cell growth and development, immune function and metabolic control [15, 16]. How to Use: Take one (1) softgel daily with food, or as recommended by a healthcare practitioner.