Vitamin D-5000Thornes D 5,000 contains 5,000 IU of high quality vitamin D3 and is NSF Certified for Sport. Although it is well known that direct sunlight is a natural source of vitamin D, many individuals, especially the elderly, dont get enough vitamin D from sunlight or from their diet. Be sure you get the vitamin D your body needs with Thornes easily absorbed Vitamin D 5,000.